Notes

Chapter 1: Waking Up

1. I will use the term global warming to refer to the increase in the average global temperature of recent decades and to the many changes to the Earth system caused by this warming, such as changes in precipitation. Strictly speaking, climate change is a more general phenomenon, of which today’s global warming is but one example. The Earth has experienced many changes in climate over its 4.5 billions years of existence.

2. You can get this sense of plants as beings by standing silently by a beautiful tree, or by standing in front of a Van Gogh painting of trees, or by other means.

3. If you’re reading this after 2023, the human population has likely surpassed eight billion.

4. I know that not many people see this yet, and I know I’m therefore taking a risk in saying it so clearly. But I know it to be true.

5. Mohandas Gandhi. The Collected Works of Mahatma Gandhi, Vol. 13 (1913), Ch. 153, page 241. [online]. gandhiserve.org/cwmg/VOL013.PDF. Emphasis mine.

Chapter 2: Beyond Green

1. See, for example, the film An Inconvenient Truth directed by Davis Guggenheim and featuring Al Gore, 2006, DVD; or Bill McKibben. Eaarth: Making a Life on a Tough New Planet. Times Books, 2010.

2. Roving marauders would be attracted by hoarded food and ammunition. A better strategy for security might be to help build a strong community and to develop skills and relationships that make you indispensable.

3. Juliet Elperin. “White House solar panels being installed this week.” Washington Post, August 15, 2013. [online]. washingtonpost.com/news/post-politics/wp/2013/08/15/white-house-solar-panels-finally-being-installed/.

Chapter 3: Global Warming: The Science

1. You can download the AR5: Intergovernmental Panel on Climate Change. “Assessment Reports.” [online]. ipcc.ch/publications_and _data/publications_and_data_reports.shtml#1. The panel is divided into three working groups. Working Group I (WG1) presents the physical evidence for global warming and resulting changes occurring in the Earth system. Working Group II (WG2) presents the current and future impacts and human adaptation strategies. Working Group III (WG3) presents our understanding of the scientific, technological, environmental, economic, and social aspects of climate change mitigation and quantifies mitigation pathways, e.g., how much warming will occur under various paths available to humanity. WG1 assesses and summarizes the scientific literature, whereas WG2 and WG3 summarize the scientific and socioeconomic literature. Each working group provides a 30-page Summary for Policymakers (SPM). Subsequent citations use these abbreviations to identify sections within this report.

2. Here are some suggestions for further reading in order of increasing level of reader commitment. (1) Yoram Bauman and Grady Klein. The Cartoon Introduction to Climate Change. Island Press, 2014. (2) The 36-page overview US National Academy of Sciences and Royal Society. Climate Change: Evidence and Causes. National Academies Press, 2014. [online]. ap.edu/catalog/18730/climate-change-evidence-and-causes. (3) David Archer. Global Warming: Understanding the Forecast, 2nd ed. Wiley, 2011 (a college text for non-science majors). (4) “The Princeton Primers in Climate,” a series of definitive but accessible books focusing on subtopics of climate, each by an expert in the sub topic: Princeton University Press. Catalogue Primers in Climate. [online]. press.princeton.edu/catalogs/series/princeton-primers-in-climate.html. I’d advise against trying to learn about climate science solely from the internet, as you’ll have to wade through a great deal of misinformation and disjointedness. That said, you can find accurate (if disjointed) information at skepticalscience.com and realclimate.com.

3. Many scientists and humanists have given this new epoch a strati-graphic name, the Anthropocene. I hesitate to follow them for three reasons. First, the word has been embraced by “ecomodernists” and others who believe, with a blind faith, that technology is the way out of our predicament. (I disagree.) Second, it makes our destructive presence feel like a geologic fact, thereby potentially reducing political will to do what we can to reduce human impact on the biosphere. Humanity still very much gets to choose just how bad global warming will get. Third, and perhaps most importantly, it presupposes that humans are the problem. In my opinion, humans aren’t the problem. A particular human culture is the problem.

4. I surveyed my Earth scientist colleagues (participating in the survey required authorship on a peer-reviewed journal paper in Earth science) and received 66 responses. When asked “How often do you feel grief about global warming,” only 10% responded “never” (a one on a scale from one to five) while half of respondents feel significant grief (with 14% and 35% choosing five and four on the scale, respectively).

5. IPCC AR5 WG1 SPM puts this temperature increase at 0.85°C, but this has since been revised upward by 24%: Mark Richardson et al. “Reconciled climate response estimates from climate models and the energy budget of Earth.” Nature Climate Change 6 (2016). [online]. doi:10.1038/nclimate3066. Temperature will increase to about 1.2°C by 2020 (2015 was already 1.1°C to 1.3°C above the pre-industrial baseline, but this was just a single year), and 1.4°C by 2030. These projections are linear extrapolations based on the observed warming of 0.12°C per decade between 1951 and 2012.

6. Camilo Mora et al. “The projected timing of climate departure from recent variability.” Nature 502 (2013). doi:10.1038/nature12540.

7. Models are tools for predicting how variables might change in the future. A global climate model is software code that runs on super computers and represents physical, chemical, and biological processes in the atmosphere, ocean, land, and ice. Earth system models are global climate models that explicitly model the carbon cycle. These models represent the Earth by dividing it into three-dimensional grid cells; horizontal resolution is typically about 100 km, although this is falling as computers get faster. At each time step, variables in every grid cell (such as temperatures, cloud amounts, sea ice amounts, etc.) are updated based on values from the previous time step and values from neighboring grid cells.

8. The business-as-usual scenario, named “RCP 8.5,” was described in Keywan Riahi et al. “RCP 8.5: A scenario of comparatively high greenhouse gas emissions.” Climatic Change 109 (1–2) (2011). [online]. doi:10.1007/s10584-011-0149-y. The mitigation scenario, named “RCP 4.5,” is described in Allison M. Thomson et al. “RCP 4.5: A pathway for stabilization of radiative forcing by 2100.” Climatic Change 109 (1–2) (2011). [online]. doi:10.1007/s10584-011-0151-4.

9. These results used a model experiment called “historicalNat” to produce estimates of the range of background variability. In the historicalNat experiment, the models ran from 1860 to 2005 with no anthropogenic CO₂ emissions, allowing for a pure comparison with the two RCP runs. However, only 17 climate models actually ran historicalNat, whereas 39 models ran an experiment called “historical” which included observed changes in atmospheric composition, including anthropogenic CO₂ emissions. Mora et al. also report results using the historical experiment as the background variability. Because this already includes some warming, the climate departure dates relative to it are delayed relative to the historicalNat results, to 2047 for RCP 8.5 (this is a mean of the 39 models, with a standard error of three years) and 2069 for RCP 4.5 (with a standard error of four years). However, these results are clearly biased due to the anthropogenic warming in the background. The results from the historicalNat do not have this bias. Mora et al. chose to highlight the biased results in order to be more conservative; in my opinion, this was a mistake. In science, it’s always best to report whatever is closest to the truth, to the best of your knowledge.

10. Note that surface temperature is just one variable in the Earth system. Any variable can be analyzed for anthropogenic departure. For ex ample, global departure has already occurred for ocean surface acidity from anthropogenic CO₂ dissolved in the ocean.

11. I therefore suggest we mitigate as if our lives depend on it. I personally don’t think there’s anything more important for humanity to do at this time.

12. Thanks to Jan Sedlacek for providing the underlying multi-model mean data, from which I created this black-and-white version of Figure 12.5 from IPCC AR5 WG1 (a.k.a. Matthew Collins et al. “Long-term Climate Change: Projections, Commitments and Irreversibility” in T. F. Stocker et al., eds. Climate Change 2013: The Physical Science Basis. Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, 2013, p. 1039).

13. The number gives the approximate radiative forcing in watts per square meter (W/m2) in the year 2100 for the scenario. We’ll discuss radiative forcing in detail later in this chapter.

14. Jasper van Vliet et al. “Meeting radiative forcing targets under delayed participation.” Energy Economics 31 (2009). [online]. doi:10.1016/j.eneco.2009.06.010.

15. See IPCC AR5 WG3 Chapter 12, Table 12.2. Predictions are the multi-model means. Uncertainties are one standard deviation of the multi-model distribution. Note that emissions predictions beyond 2100 require extended RCP scenarios, which make simple (and possibly simplistic) assumptions about greenhouse gas and aerosol emissions beyond 2100. As model predictions extend further into the future, they naturally become increasingly uncertain.

16. J. D. Annan and J. C. Hargreaves, J. C. “A new global reconstruction of temperature changes at the Last Glacial Maximum.” Climate of the Past 9 (2013). [online]. doi: 10.5194/cp-9-367-2013.

17. Lorraine E. Lisiecki and Maureen E. Raymo. “A Pliocene-Pleistocene stack of 57 globally distributed benthic δ¹⁸O records.” Paleoceanology 20(1) (2005). [online]. doi:10.1029/2004PA001071.

18. James Hansen et al. “Climate sensitivity, sea level and atmospheric carbon dioxide.” Philosophical Transactions of the Royal Society A 371 (2013). [online]. doi:10.1098/rsta.2012.0294.

19. A key reason the swaths in Figure 3.2 are so wide is due to a “known unknown,” our uncertainty about how clouds work. (One of my research interests is low-altitude clouds: how they interact with the Earth system, how they change as the planet warms, and how their changes in turn affect warming.) The global models used to make climate projections divide the Earth into grid cells that are currently about a degree latitude and a degree longitude in size—much larger than individual clouds. This means the models must statistically approximate cloud variables, such as the total cloud cover at different altitudes, in each grid cell. Each model does this differently, and one result of this is that the models differ on how clouds interact with atmospheric dynamics, and how they’ll change as the planet continues to warm. For example, some models predict an increase in low clouds with warming, while others predict a decrease. Low clouds (such as the stratocumulus clouds on an overcast day) cool the planet by reflecting sunlight back to space: models with more low clouds tend to predict cooler temperatures, and models with fewer low clouds predict warmer temperatures.

20. This temperature would be set by a simple balance between absorbed solar radiation and emitted thermal infrared radiation. There would not even be clouds reflecting sunlight and interacting with outgoing infrared light, because water vapor is among the greenhouse gases we’ve just imagined away. The Earth’s actual average surface temperature, with the greenhouse effect, is about 15°C.

21. Inferred from data from NOAA Earth System Research Laboratory. “Trends in Atmospheric Carbon Dioxide.” [online]. esrl.noaa.gov/gmd/ccgg/trends/global.html.

22. The rate of heat conduction between two sides of a conducting object (like our blanket) is proportional to the difference in temperature between them.

23. This absorption is quantum-mechanical. Infrared photons coming up from the Earth have a range of frequencies following the Planck spectrum. When an infrared photon hits a molecule of water or CO₂ (or another greenhouse gas) with the quantum of energy needed to excite the molecule from its ground state to e.g., a bending vibrational state (i.e., molecules can only absorb photons of certain frequencies, but the photon happens to have one of these quantum-mechanically allowed frequencies), it can be absorbed by the molecule, which then starts to vibrate. After some time, the molecule will de-excite and emit a photon in a random direction, possibly out to space. However, in the lower atmosphere, the molecule is more likely to collide with some other molecule first. When this collision occurs, it can transfer energy to the molecule it collides with. The net result is that most of the upwelling infrared photons from the Earth’s surface fail to escape into space, and instead warm up the lower atmosphere.

24. Measuring the global mean reflected solar energy from space is challenging; satellites records show no clear trend. While you might think melting snow and ice would cause more solar energy to be absorbed (and this does happen regionally), cloud patterns can change and compensate in the global mean.

25. The residence time is an estimate of how long it would take for the excess over preindustrial levels to be halved. This doesn’t mean the next halving will take the same amount of time (i.e., the decay is not necessarily a single exponential process). CO₂ is chemically inert and has a long residence time, while CH₄ is chemically reactive and has a short residence time.

26. These values are from Drew T. Shindell et al. “Improved attribution of climate forcing to emissions.” Science 326 (2009), at p. 716. [online]. doi:10.1126/science.1174760. For a given gas, GWP estimates depend on which direct and indirect warming effects from that gas are included in the estimate. For example, the IPCC GWP estimates for methane do not include gas-aerosol interactions, in which methane suppresses the formation of aerosols which cool the climate; excluding this effect, the IPCC AR5 estimates GWP₂₀ of only 86.

27. PCC AR5 WG1 Chapter 8, p. 714 gives a GWP₂₀ of 264 and a GWP₁₀₀ of 265 with uncertainties 20% and 30% respectively.

28. Estimates of percentage of current greenhouse radiative forcing in this section are made by dividing the forcing in question by the total positive forcing from greenhouse gases: CO₂ + CH₄ + halocarbons + N₂O + CO + NMVOC = 3.33 W/m2. Note that I’ve omitted NMVOC from the discussion for simplicity (they contribute 0.1 [0.05 to 0.15] W/m2 and are declining); for details see IPCC AR5 WG1 Chapter 2.

29. IPCC AR5 WG1 Chapter 8, p. 731.

30. This 5% factors in the cooling effect of ozone destruction.

31. Shindell et al. “Improved attribution of climate forcing to emissions.”

32. This includes formation of ozone and stratospheric water vapor, but not gas-aerosol interactions.

33. IPCC AR5 WG3 SPM.

34. From my own calculation using a methane GWP of 105, based on the 16% figure for a methane GWP of 34, with the other greenhouse gas GWPs fixed.

35. IPCC AR5 WG1 Chapter 2, p. 167.

36. IPCC AR5 WG1 Chapter 6, p. 541.

37. Note that the IPCC estimate of methane emissions from fossil fuel production relies on a 2012 EPA estimate: US EPA, Office of Atmospheric Programs. “Global anthropogenic non-CO₂ greenhouse gas emissions: 1990–2030.” EPA Report # EPA 430-R-12-006. [online]. epa.gov/climatechange/Downloads/EPAactivities/EPA_Global_NonCO₂_Projections_Dec2012.pdf. Newer studies are finding that this estimate may be significantly too low.

38. The 2002 to 2011 annual average.

39. IPCC AR5 WG1 SPM. Between 2002 and 2011, on average humans emitted 8.3 [7.6–9.0] gigatonnes of carbon (GtC) per year from burning fossil fuels and making cement, and 0.9 [0.1–1.7] GtC per year from land-use change. Cement production accounts for about 4% of human CO₂ emissions: IPCC AR5 WG1 Chapter 6, p. 489.

40. IPCC AR5 WG1 Chapter 6, p. 486.

41. The measurement process is described on the website of the Carbon Cycle Greenhouse Gases Group of the Global Monitoring Division of the Earth System Research Laboratory of the National Oceanic and Atmospheric Administration (online at esrl.noaa.gov/gmd/ccgg/). In a nutshell: Scientists at the top of the mountain measure the CO₂ fraction in dried air via infrared absorption. Infrared light shines into a glass tube containing air. An infrared detector on the far side of the tube measures the transmitted infrared light. CO₂ blocks infrared light (which is also why it warms the Earth), so the more CO₂ in the air, the less infrared light makes it to the detector.

The output of the detector is a voltage which increases with the power of the incident infrared radiation. Once calibrated, that voltage can be converted to the CO₂ fraction to within 0.2 ppmv (parts per million by volume). The trickiest part of the measurement is calibration: accurately and precisely converting the detector voltage to the fraction of CO₂ in the air. This is done with three reference mixtures of air, themselves carefully calibrated, which are turned on once per hour for four minutes each. The three data points are fitted quadratically, giving the conversion function. Systematic errors are guarded against by checking prepared “target” samples of air of various and known CO₂ fractions, and by sending flasks of air to National Institute of Standards and Technology (NIST) in Boulder, Colorado, for independent measurement.

42. Data are from US NOAA. “A Global Network for Measurements of Greenhouse Gases in the Atmosphere.” [online]. esrl.noaa.gov/gmd/ccgg/.

43. I used the function y = 280 + (1 + a)^t-b. The best fit values (on annual mean values from 1959 to 2016) are b = 1790 and a = 0.0217.

44. The record going back to about 400,000 years ago comes from an ice core taken near Vostok Station, Antarctica: J. R. Petit et al. “Climate and atmospheric history of the past 420,000 years from the Vostok Ice Core, Antarctica.” Nature 399 (1999). [online]. doi:10.1038/20859. The CO₂ fraction was measured by gas chromatography. Because this is a “proxy” record, it has error bars in both axes (time and CO₂ fraction). The error bar in the absolute time (the x-axis) is less than ±15 ky (kiloyears) over the whole record, and less than ±5 ky over the last 110,000 years. The error bar in the CO₂ fraction (the y-axis) is ±3 ppmv. The record going back to about 800,000 years ago comes from an ice core taken on Dome C, Antarctica: Lüthi et al. “High-resolution carbon dioxide concentration record 650,000–800,000 years before present.” Nature 453 (2008). [online]. doi:10.1038/nature06949. The record from 1,000 years ago until almost the present day comes from an Antarctic ice core taken on the Law Dome: Etheridge et al. “Natural and anthropogenic changes in atmospheric CO₂ over the last 1000 years from air in Antarctic ice and firn.” Journal of Geophysical Research 101 (1996). [online]. doi:10.1029/95JD03410.

45. Although the error in absolute time at this point in the record is around ±5 ky, the error in time durations is much smaller.

46. Data from IPCC AR5 WG3, Chapters 7–11. Note that this table preserves the GWP₁₀₀ basis used by the IPCC. In other words, methane is assigned the relatively low GWP of 21, arguably making it under-represented in this table.

47. M. MacLeod et al. Greenhouse gas emissions from pig and chicken supply chains—A global life cycle assessment. Food and Agriculture Organization of the United Nations (FAO), 2013. [online]. fao.org/docrep/018/i3460e/i3460e.pdf; C. Opio et al. Greenhouse gas emissions from ruminant supply chains: A global life cycle assessment. Food and Agriculture Organization of the United Nations (FAO), 2013. [online]. fao.org/docrep/018/i3461e/i3461e.pdf.

48. IPCC AR5 WG3 Chapter 8, p. 605.

49. The data are from the Berkeley Earth. Land + Ocean surface temperature time series: Berkley Earth. Land + Ocean Data. [online]. berkeleyearth.org/land-and-ocean-data/.

50. Robert Rohde et al. “Berkeley Earth temperature averaging process.” Geoinformatics & Geostatistics: An Overview 1:2 (2013). [online]. scitechnol.com/berkeley-earth-temperature-averaging-process-IpUG.pdf. The ocean data are from HadSST: Asia-Pacific Data-Research Centre. Data documentation: Hadley Centre SST data set (HadSST). [online]. apdrc.soest.hawaii.edu/datadoc/hadsst.php.

51. Mark Richardson et al. “Reconciled climate response estimates from climate models and the energy budget of Earth.” Nature Climate Change 6 (2016). [online]. doi:10.1038/nclimate3066.

52. Other data sets tell the same story. According to the NASA data set, for ex ample, 16 of the 17 warmest years on record occurred between 2001 and 2016: US NASA. “GISS Surface Temperature Analysis (GISTEMP).” [online]. data.giss.nasa.gov/gistemp/. For a summary article: Justin Gillis. “Earth sets a temperature record for the third straight year.” New York Times, January 18, 2017. [online]. nytimes.com/2017/01/18/science/earth-highest-temperature-record.html.

53. Perhaps if you’re reading this in 2025, you’re thinking back, wistfully, to that much cooler year, 2016. When I read something about climate change written in the past, I often find myself thinking this.

54. Sydney Levitus et al. “Anthropogenic warming of Earth’s climate system.” Science 292(5515) (2001). [online]. doi:10.1126/science.1058154.

55. Data from NOAA, Ocean Climate Laboratory, Global Ocean Heat and Salt Content. “Basin time series of heat content (product, 0–2000 meters).” [online]. nodc.noaa.gov/OC5/3M_HEAT_CONTENT/basin_data.html. Data described in S. Levitus et al. “World ocean heat content and thermosteric sea level change (0–2000 m), 1955–2010.” Geophysical Research Letters 39 (2012). [online]. doi:10.1029/2012GL051106.

56. Noah Diffenbaugh and Christopher Field. “Changes in ecologically critical terrestrial climate conditions.” Science 341 (6145) (2013). doi:10.1126/science.1237123.

57. IPCC AR5 WG1 SPM. Over these same periods, the rate of Antarctic ice sheet loss has increased from 30 Gt per year to 147 Gt per year, a four-fold increase.

58. Fiammetta Straneo and Patrick Heimbach. “North Atlantic warming and the retreat of Greenland’s outlet glaciers.” Nature 504 (2013). [online]. doi:10.1038/nature12854.

59. IPCC AR5 WG1 SPM. Some of this sea level rise is from ice melt, and some is from thermal expansion of water.

60. Christopher S. Watson et al. “Unabated global mean sea-level rise over the satellite altimeter era.” Nature Climate Change 5 (2015). [online]. doi:10.1038/nclimate2635.

61. IPCC AR5 WG1 SPM.

62. Ibid.

63. Additional changes include considerable reduction in Siberian perma frost thickness and extent; decreasing northern hemisphere snow covered area (June snow cover is decreasing by 12% per decade); and non-surface atmospheric warming in the lower atmosphere as measured by satellites. I have to be honest: to me, these and other changes seem surreal, like bad science fiction. But they’re as real and as verifiable as a melting ice cube.

64. I made this version of figure SPM.5 from IPCC AR5 WG1 SPM. Source: T. F. Stocker et al., eds. Climate Change 2013.

65. Mike Lockwood. “Solar Influence on Global and Regional Climates.” Surveys in Geophysics 33(3) (2012). [online]. doi:10.1007/s10712-012-9181-3.

66. Note that this cooling from ozone destruction by halocarbons represents a direct connection between the Antarctic ozone hole and global warming. The magnitude of the negative forcing from global depletion of the ozone layer is about 5% of the magnitude of the net forcing (which, of course, is positive), and some of this negative forcing is from the ozone hole. In this sense the ozone hole does play a role in global warming, albeit a small one.

67. David Herring. “Earth’s Temperature Tracker.” NASA. Earth Observatory website, November 5, 2007. [online]. earthobservatory.nasa.gov/Features/GISSTemperature/giss_temperature.php/.

68. But what is black carbon? Strangely, no lab has a sample of black carbon in a vial, and there is no agreed-upon definition for the substance, which can perhaps best be described as “light-absorbing refractory carbonaceous matter of uncertain character.” For example: P. R. Buseck et al. “Are black carbon and soot the same?” Atmospheric Chemistry and Physics Discussions 12 (2012). [online]. doi:10.5194/acpd-12-24821-201.

69. Kristina Pistone et al. “Observational determination of albedo decrease caused by vanishing Arctic sea ice.” Proceedings of the National Academy of Sciences 111(9) (2014). [online]. doi:10.1073/pnas.1318201111.

70. IPCC AR5 WG1 Chapter 7, p. 592. In 2015, the cloud response was still the largest source of uncertainty in estimating climate sensitivity. Three positive feedbacks are known with varying degrees of confidence. The most robust is an increase in high cloud top height with warming. This is a positive feedback because higher clouds trap more infrared radiation. The second positive cloud feedback, accepted with medium confidence (IPCC AR5 WG1 Chapter 7, p. 589) is a global shift of cloud patterns to the poles, where there’s less sunlight; this decreases albedo. The third positive cloud feedback, accepted with low confidence, is a decrease in subtropical low clouds. Global models give a wide range of magnitudes, and a few even give a negative feedback.

71. Graeme L. Stephens et al. “The albedo of Earth.” Reviews of Geophysics 53 (2015). [online]. doi:10.1002/2014RG000449.

72. Yadong Sun et al. “Lethally hot temperatures during the early Triassic greenhouse.” Science 338(6105) (2012). [online]. doi:10.1126/science.1224126.

73. Reservoir size estimates in Table 3.3 are based on estimates from IPCC AR5 WG1 Chapter 6, and P. Falkowski et al. “The global carbon cycle: A test of our knowledge of Earth as a system.” Science 290(5490) (2000). [online]. doi:10.1126/science.290.5490.291.

74. IPCC AR5 WG1 SPM, p. 12.

75. David Archer. The Global Carbon Cycle. Princeton, 2010. For quantitative details about the carbon cycle response to increased CO₂ and warming, see IPCC AR5 WG1 Chapter 6, Figure 6.20 and accompanying text.

76. IPCC AR5 WG1 Chapter 6, p. 492. In discussions of the carbon cycle, the conventional unit is gigatonnes of carbon (GtC, 1 Gt = 109 t) or equivalently petagrams of carbon (PgC, 1 Pg = 1015 g). Elsewhere in the book, I may measure the mass of CO₂ instead of the mass of the carbon atoms in CO₂. One GtC = 3.67 GtCO₂.

77. IPCC AR5 WG1 SPM, p. 12.

78. S. Khatiwala et al. “Reconstruction of the history of anthropogenic CO₂ concentrations in the ocean.” Nature 462 (2009). [online]. doi:10.1038/nature08526.

79. Archer. The Global Carbon Cycle, p. 177.

80. W. Kolby Smith et al. “Large divergence of satellite and Earth system model estimates of global terrestrial CO₂ fertilization.” Nature Climate Change 6 (2016). [online]. doi:10.1038/nclimate2879.

81. T. W. Crowther et al. “Quantifying global soil carbon losses in response to warming.” Nature 540 (2016). [online]. doi:10.1038/nature20150.

82. Craig D. Allen et al. “A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests.” Forest Ecology and Management 259 (2010). [online]. doi:10.1016/j.foreco.2009.09.001.

83. Paulo Montiero Brando et al. “Abrupt increases in Amazonian tree mortality due to drought-fire interactions.” Proceedings of the National Academy of Sciences 111(17) (2014). [online]. doi:10.1073/pnas.1305499111.

84. Ibid. and Oliver L. Phillips et al. “Drought sensitivity of the Amazon rainforest.” Science 323(5919) (2009). [online]. doi:10.1126/science.1164033.

85. Pierre Friedlingstein et al. “Uncertainties in CMIP5 Climate Projections due to Carbon Cycle Feedbacks.” Journal of Climate 27 (2014). [online]. doi:10.1175/JCLI-D-12-00579.1.

86. David Archer et al. “Ocean methane hydrates as a slow tipping point in the global carbon cycle.” Proceedings of the National Academy of Sciences 106(49) (2009). [online]. doi:10.1073/pnas.0800885105.

87. Archer. The Global Carbon Cycle, p. 178.

88. IPCC AR5 WG1 Chapter 6, p. 467. The IPCC cites 9.5 ± 0.8 GtC, but I have subtracted cement production, which accounted for roughly 4% of total CO₂ emissions in 2000–2009 (IPCC AR5 WG1 Chapter 6, p. 489). The 2002–2011 average (including cement production) was 8.3 GtC per year.

89. IPCC AR5 WG3 Chapter 5, p. 357.

90. Data from IPCC AR5 WG1 Chapter 6, Table 6.1 and Figure 6.1.

91. The formula is CO₂ + CO₃^2- + H₂O ←→ ₂HCO₃^-.

92. The formula is CaCO₃ ←→ Ca²⁺ + CO₃^2-. Because the CO₂ is reacting with carbonate ions, CO₃^2-, this reaction is pushed to the right.

93. I’ve taken data from the BP corporation’s Statistical Review of World Energy 2012, which goes back to 1965. For the current edition, see BOP Global. Statistical Review of World Energy. [online]. bp.com/en/global/corporate/energy-economics/statistical-review-of-world-energy.html.

94. Increasing airborne CO₂ by 7.8 gigatonnes is equivalent to raising the atmospheric fraction by 1 ppm. (Note that emitting a certain amount of CO₂ is not the same as increasing airborne CO₂ by that amount, since some of the emissions would go into other carbon reservoirs, the land and ocean sinks.)

95. According to IPCC AR5 WG1 SPM, from 1750 to 2011, humans emitted 375 [345 to 405] GtC from fossil fuel burning and 180 [100 to 260] GtC from deforestation. A more careful analysis would incorporate actual deforestation and cement production CO₂ emission data as a function of time.

96. IPCC AR5 WG1 Chapter 6, p. 493.

97. Svante Arrhenius presented his paper, “On the Influence of Carbonic Acid in the Air Upon the Temperature of the Ground,” in 1895.

98. Rare heavy water molecules (containing either ¹⁸O or D, heavier isotopes of ¹⁶O and H respectively) evaporate at lower rates and condense at higher rates than H₂O at a given temperature, and these rate differences become more pronounced as temperature decreases. Knowledge of the temperature relationship of these rates therefore allows us to estimate the Earth’s temperature at past times. See J. Jouzel et al. “Orbital and millennial Antarctic climate variability over the past 800,000 years.” Science 317(5839) (2007). [online]. doi:10.1126/science.1141038.

99. Dome C data from: NOAA World Data Center for Paleoclimatology. “Ice Core.” [online]. ncdc.noaa.gov/paleo/icecore/antarctica/domec/domec_epica_data.html.

100. The driver of climate change over this 800,000-year period was subtle periodic changes in the Earth’s orbit.

101. Note that CO₂ changes of only about 80 ppm corresponded in the ice core records to Antarctic surface temperature changes of about 12°C. By comparison, as of 2016 we’ve already increased the atmospheric CO₂ concentration by 120 ppm over preindustrial levels, and the Earth system is still in the process of adjusting to a new equilibrium, with positive feedbacks kicking in and more warming in the pipeline. This might seem to imply a 12°C increase, but remember, the Earth system is complicated. The observed 12°C increases occurred when an ice-covered Earth came out of glacial periods, and about ⅔ of the warming was due to albedo change as ice melted. Today, we’re not in a glacial period, so we won’t experience such a large albedo amplification; our primary forcing is from greenhouse gases, which accounted for about ⅓ of the glacial/interglacial amplification. See RealClimate (Eric Steig). “The lag between temperature and CO₂.” April 27, 2007. [online]. realclimate.org/index.php/archives/2007/04/the-lag-between-temp-and-co2/.

Chapter 4: Global Warming: The Outlook

1. For a more complete discussion of impacts, please see the global warming books I listed in Chapter 3, note 2, or the IPCC AR5 WG2 report.

2. IPCC AR5 WG1 SPM.

3. Jean-Marie Robine et al. “Death toll exceeded 70,000 in Europe during the summer of 2003.” Comptes Rendus Biologies 331 (2) (2008). [online]. doi:10.1016/j.crvi.2007.12.001.

4. Peter A. Stott et al. “Human contribution to the European heatwave of 2003.” Nature 432 (2004). [online]. doi:10.1038/nature03089.

5. Nikolaos Christidis et al. “Dramatically increasing chance of extremely hot summers since the 2003 European heatwave.” Nature Climate Change 5 (2015). [online]. doi:10.1038/nclimate2468.

6. I-Ching Chen et al. “Rapid range shifts of species associated with high levels of climate warming.” Science 333(6045) (2011). [online]. doi:10.1126/science.1206432; Kai Zhu et al. “Failure to migrate: Lack of tree range expansion in response to climate change.” Global Change Biology 18(3) (2011). [online]. doi:10.1111/j.1365-2486.2011.02571.x; Harald Pauli et al. “Recent plant diversity changes on Europe’s mountain summits.” Science 336(6079) (2012). [online]. doi:10.1126 / science.1219033.

7. Elvira S. Poloczanska et al. “Global imprint of climate change on marine life.” Nature Climate Change 3 (2013). [online]. doi:10.1038/nclimate1958.

8. Chris D. Thomas et al. “Extinction risk from climate change.” Nature 427 (2004). [online]. doi:10.1038/nature02121.

9. Francesca A. McInerney and Scott L. Wing. “The Paleocene-Eocene Thermal Maximum: A Perturbation of Carbon Cycle, Climate, and Biosphere with Implications for the Future.” Annual Review of Earth and Planetary Sciences 39 (2011). [online]. doi:10.1146/annurev-earth-040610-133431.

10. E. O. Wilson. Half-Earth: Our Planet’s Fight for Life. Liveright, 2016, p. 14.

11. Mark C. Urban. “Accelerating extinction risk from climate change.” Science 348(6234) (2015). [online]. doi:10.1126/science.aaa4984.

12. Mora et al. “The projected timing of climate departure.”

13. IPCC AR5 WG1 SPM.

14. Ibid.

15. Andreas F. Prein et al. “The future intensification of hourly precipitation extremes.” Nature Climate Change 7 (2017). [online]. doi:10.1038/nclimate3168.

16. IPCC AR5 WG1 Chapter 2, p. 204.

17. IPCC AR5 WG1 Chapter 2, p. 223.

18. At the time of this writing, a definitive global warming attribution for specific droughts has not been made, but evidence is mounting.

19. IPCC AR5 WG1 Chapter 2, p. 227.

20. Benjamin I. Cook, Toby R. Ault, and Jason E. Smerdon. “Unprecedented 21st century drought risk in the American Southwest and Central Plains.” Science Advances 1(1) (2015). [online]. doi:10.1126/sciadv.1400082.

21. Daniel Griffin and Kevin J. Anchukaitis. “How unusual is the 2012– 2014 California drought?” Geophysical Research Letters 41 (2014). [online]. doi:10.1002/2014GL062433.

22. Mike McPhate. “California today: More than 100 million trees are dead. What now?” New York Times, November 21, 2016. [online]. nytimes.com/2016/11/21/us/california-today-dead-trees-forests.html.

23. John T. Abatzoglou and A. Park Williams. “Impact of anthropogenic climate change on wildfire across western US forests.” Proceedings of the National Academy of Sciences 113(42) (2016). [online]. doi:10.1073 / pnas.1607171113.

24. Tatiana Schlossberg. “Climate change blamed for half of increased fire danger.” New York Times, October 10, 2016. [online]. nytimes.com/2016/10/11/science/climate-change-forest-fires.html.

25. IPCC AR5 WG2 SPM.

26. Corey Watts. “A brewing storm: The climate change risks to coffee.” Climate Institute, 2016. [online]. climateinstitute.org.au/coffee.html. Climate-related threats to the global coffee crop include drought, rising temperatures, and increases in pests and disease.

27. IPCC AR5 WG2 Chapter 5, p. 364.

28. Ibid.

29. Stephane Hallegatte et al. “Future flood losses in major coastal cities.” Nature Climate Change 3 (2013). [online]. doi:10.1038/nclimate1979.

30. Ian Urbina. “Perils of climate change could swamp coastal real estate.” New York Times, November 24, 2016. [online]. nytimes.com/2016/11/24/science/global-warming-coastal-real-estate.html.

31. IPCC AR5 WG2 Chapter 5, p. 364.

32. Eric Rignot et al. “Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith, and Kohler glaciers, West Antarctica, from 1992 to 2011.” Geophysical Research Letters 41(10) (2014). [online]. doi:10.1002/2014GL060140; Johannes Feldmann and Anders Levermann. “Collapse of the West Antarctic Ice Sheet after local destabilization of the Amundsen Basin.” Proceedings of the National Academy of Sciences 112(46) (2015). [online]. doi:10.1073/ pnas.1512482112.

33. Feldmann and Levermann. “Collapse of the West Antarctic Ice Sheet after local destabilization of the Amundsen Basin.” Ian Joughin et al. “Marine ice sheet collapse potentially under way for the Thwaites Glacier Basin, West Antarctica.” Science 344(6184) (2014). [online]. doi:10.1126/science.1249055.

34. Robert M. DeConto and David Pollard. “Contribution of Antarctica to past and future sea-level rise.” Nature 531 (2016). [online]. doi:10.1038/nature17145.

35. Colin P. Kelley et al. “Climate change in the Fertile Crescent and implications of the recent Syrian drought.” Publications of the National Academy of Sciences 112(11) (2015). [online]. doi:10.1073 / pnas.1421533112; John Wendle. “The ominous story of Syria’s climate refugees.” Scientific American, December 17, 2015. [online]. scientific american.com/article/ominous-story-of-syria-climate-refugees/.

36. Solomon M. Hsiang et al. “Quantifying the influence of climate on human conflict.” Science 341(6151) (2013). [online]. doi:10.1126/science.1235367.

37. W. J. Hennigan. “Climate change is real: Just ask the Pentagon.” Los Angeles Times, November 11, 2016. [online]. latimes.com/nation/la-na-military-climate-change-20161103-story.html.

38. IPCC AR5 WG2 SPM.

39. IPCC AR5 WG1 Chapter 6, p. 544.

40. Archer. The Global Carbon Cycle.

41. McInerney and Wing. “The Paleocene-Eocene Thermal Maximum.”

42. James W. Kirchner and Anne Weil. “Delayed biological recovery from extinctions throughout the fossil record.” Nature 404 (2000). [online]. doi:10.1038/35004564.

43. In the survey of Earth scientists I mentioned in Chapter 3, when asked “Does it bother you, personally, to burn fossil fuels?” 52% said “yes,” 41% said “sometimes,” and 7% said “no” (58 responses).

44. According to the Royal Society: Geoengineering the climate: Science, governance and uncertainty. RS Policy document 10/09, 2009. [online]. royalsociety.org/topics-policy/publications/2009/geoengineering-climate/.

45. Lyla L. Taylor et al. “Enhanced weathering strategies for stabilizing climate and averting ocean acidification.” Nature Climate Change 6 (2016). [online]. doi:10.1038/nclimate2882.

46. It takes about two tonnes of silicate rock to remove one tonne of CO₂. But one tonne of carbon mined from the ground releases about four tonnes of CO₂ gas when burned. So every tonne of carbon mined would require about eight tonnes of silicate rock to mitigate.

47. Ziahua Liu et al. “Atmospheric CO₂ sink: Silicate weathering or carbonate weathering?” Applied Geochemistry Vol. 26 (Supplement) (2011). [online]. doi: dx.doi.org/10.1016/j.apgeochem.2011.03.085.

48. Royal Society. Geoengineering the climate, p. 49.

49. Graeme L. Stephens et al. “The albedo of Earth.” Reviews of Geophysics 53 (2015). [online]. doi:10.1002/2014RG000449.

50. H. Damon Matthews and Ken Caldeira. “Transient climate-carbon simulations of planetary geoengineering.” Publications of the National Academy of Sciences 104(24) (2007). [online]. doi: 10.1073pnas.0700419104.

51. Royal Society. Geoengineering the climate, p. 32.

52. R. Lal. “Soil carbon sequestration impacts on global climate change and food security.” Science 304(5677) (2004). [online]. doi:10.1126/ science.1097396.

53. David S. Powlson et al. “Limited potential of no-till agriculture for climate change mitigation.” Nature Climate Change 4 (2014). [online]. doi:10.1038/NCLIMATE2292.

54. IPCC AR5 WG3 SPM, Figure SPM.4 and Table SPM.1. These requirements are based on the median pathways presented for each scenario.

55. Kevin Anderson. “Duality in climate science.” Nature Geoscience 8 (2015). [online]. doi:10.1038/ngeo2559.

56. IPCC AR5 synthesis report SPM. The total estimated budget from 1870 onward is 790 [695 to 858] GtC, and 520 GtC was emitted up to 2011.

57. Anderson. “Duality in climate science.”

58. In my survey of Earth scientists, when asked “Do you believe that we will stay below the 2 degree Celsius threshold?” 92% said “no” while 8% said “yes” (60 responses).

59. Christophe McGlade and Paul Ekins. “The geographical distribution of fossil fuels unused when limiting global warming to 2°C.” Nature 517 (2015). [online]. doi:10.1038/nature14016.

60. I looked at current costs of wind, solar voltaic, concentrating solar trough, and nuclear energy, and electrical storage; made some basic assumptions about energy storage; and assumed that as a nation we can cut our electricity use in half. This led to an estimate that electrical decarbonization would cost about $1 trillion. This is about $3,000 per person, or alternatively the combined net worth of the twenty or so richest Americans. By comparison, by 2015, the “war on terror” had cost US taxpayers $1.7 trillion: Niall McCarthy. “The war on terror has cost taxpayers $1.7 trillion.’’ Forbes, February 3 2015. [online]. forbes.com/sites/niallmccarthy/2015/02/03/the-war-on-terror-has-cost-taxpayers-1-7-trillion-infographic/#75a6f1255cf0.

61. Three quarters of this was from hydropower. World Energy Council. “Variable renewable energy sources integration in electricity systems 2016: How to get it right.” (2016). [online]. worldenergy.org/publications/2016/variable-renewable-energy-sources-integration-in-electricity-systems-2016-how-to-get-it-right/.

62. Kanyakrit Vongkiatkajorn. “California just took a huge step in the fight against climate change.” Mother Jones, September 8, 2016. [online]. motherjones.com/environment/2016/09/california-passes-sb-32-groundbreaking-climate-legislation.

63. It’s important to realize that no scientist will say he or she is 100% certain about any future outcome, ever. No one can be 100% certain about any event in the future. There should be a word in our language which scientists can use to mean “certain beyond any reasonable doubt” and which non-scientists hear as “absolutely certain.” I’ve chosen to use the word “unequivocal” for this purpose.

64. Keynyn Brysse et al. “Climate change prediction: Erring on the side of least drama?” Global Environmental Change 23(1) (2013). [online]. doi:10.1016/j.gloenvcha.2012.10.008.

Chapter 5: Growth Always Ends

1. With the spacecraft New Horizon’s 2015 flyby of Pluto, NASA has now explored every world in our solar system. One thing we’ve learned is that every planet in our system except Earth is incredibly hostile to human life. Another thing we’ve learned is that space travel is very difficult: NASA workers hold their breath at every critical juncture of a mission (e.g., launch, deployment, orbit insertion, landing) as there are so many ways for the mission to fail. In my opinion, it’s likely that we’ll identify a plausibly Earth-like planet around another star within the lifetimes of humans alive today. However, even sending just a handful of people to this world would be far beyond our current technology—we can’t even run a Biosphere 2 here on Earth. For a good discussion of the immense difficulties of interstellar travel, see: Tom Murphy. “Why Not Space?” Do The Math blog, October 12, 2011. [online]. physics.ucsd.edu/do-the-math/2011/10 / why-not-space/.

2. I heard a basic version of this story from Chris Martenson, who heard it from Albert Allen Bartlett.

3. The stadium is a cylinder with 207,000 square meters of cross-sectional area and 60 meters of height.

4. We assume 0.05 milliliter of water per drop.

5. Fortunately, one of Bond’s hobbies is freediving. He lowers his heart rate, and using a minimum of motion, he finishes escaping from the handcuffs and swims up to air. Transformed by the experience, he turns in his license to kill and becomes a first-rate high school math teacher.

6. For math people, here’s why: the exponential function can be written y/y₀ = e^ln(1+r)t = (1 + r)^t where t is time, y₀ is the value of y at t = 0, and r is the fractional growth rate per unit of time (i.e., R = 100r). After one doubling, when t = t_d, we have 2 = (1 + r)^td. Taking the logarithm of both sides gives t_d = ln(2)/ln(1 + r) ≈0.693/r for small r (e.g., less than 0.15, or 15%).

7. Extrapolating this simple 2.2% growth per year into the past agrees reasonably well with actual historical concentrations, which were about 315 ppm CO₂ in 1960 and 350 ppm CO₂ in 1990. The minor discrepancies arise because the historical growth rate used to be less than 2.2% per year. But in the early stages of growth, inaccuracies due to the growth rate are small compared to the 280 ppm baseline.

8. Data are from: US Census Bureau. “World Population: Historical Estimates of World Population.” International Data Base, revised September 27, 2016. [online]. census.gov/population/international/data/worldpop/table_history.php. Where higher and lower estimates were provided, I have taken the mean.

9. Additional data and projections into the future are from: United Nations, Population Division. World Population Prospects: The 2012 Revision, medium fertility variant. [online]. esa.un.org/unpd/wpp/Publications/.

10. Data from: US Census Bureau. “World Population: Total Midyear Population for the World, 1950–2050.” International Data Base, revised September 27, 2016. [online.] census.gov/population/international/data/worldpop/table_population.php.

11. Elina Pradhan. “The relationship between women’s education and fertility.” World Economic Forum, November 27, 2015. [online]. weforum.org/agenda/2015/11/the-relationship-between-womens-education-and-fertility.

12. This would be precisely true if population growth was equal across individual emissions levels, but population growth is higher in poorer countries which have lower per capita emissions. This implies that growth in per capita emissions may be a larger driver of global emissions than population growth.

13. With an 80% confidence interval of 9.6 billion to 10.0 billion.

14. With an 80% confidence interval of 10.0 billion to 12.5 billion. This projection should be taken with a grain of salt, however. For example, in 1951, the UN predicted a world population of 3 billion in 1980; but the actual was 4.4 billion, 50% higher than predicted.

15. United Nations, Population Division. World Population Prospects: The 2015 Revision. [online]. esa.un.org/unpd/wpp/Publications/.

16. Some people frame this as an either/or proposition, with proponents of capitalism calling for population control and proponents of socialism calling for a more equitable division of resources (with no need for population control). At this time, however, humans are emitting too much CO₂ into the atmosphere, and the fact is that this is a function of both our modes of resource use and our population.

17. Thomas J. Espenshade et al. “The surprising global variation in replacement fertility.” Population Research and Policy Review 22(5/6) (2003). [online]. doi:10.1023/B:POPU.0000020882.29684.8e.

18. Kristin Park. “Stigma Management among the Voluntarily Childless.” Sociological Perspectives 45(1) (2002). [online]. jstor.org/stable/10.1525/sop.2002.45.1.21.

19. Deepak K. Ray et al. “Recent patterns of crop yield growth and stagnation.” Nature Communications 3 (2012). [online]. doi:10.1038/ncomms2296.

20. Norman Borlaug. “The Green Revolution, Peace, and Humanity.” Nobel lecture, December 11, 1970. [online]. nobelprize.org/nobel_prizes/peace/laureates/1970/borlaug-lecture.html.

21. Staple crops such as wheat, rice, corn, and soybeans were bred for dwarfing (dwarf plants divert a higher fraction of their energy into carbohydrates), shorter maturation times, disease resistance, responsiveness to fertilizers and irrigation, insensitivity to herbicides, and insensitivity to day length (allowing for success in a wider range of latitudes, and allowing farmers in some regions to grow in two seasons instead of only one).

22. Engineers are modifying both plants and animals, although GMO animals have yet to take off. GMO animals include fast-growing salmon (with inserted eel genes), pigs with larger butts (with an introduced mutation), “web-spinning” goats (with inserted spider genes), and glow in the dark cats (with inserted jellyfish genes).

23. E. T. Lammerts van Bueren et al. “The need to breed crop varieties suitable for organic farming, using wheat, tomato and broccoli as examples: A review.” NJAS—Wageningen Journal of Life Sciences 58(3–4) (2011). [online]. doi:10.1016/j.njas.2010.04.001.

24. Rhys E. Green et al. “Farming and the fate of wild nature.” Science 307(5709) (2005). [online]. doi:10.1126/science.1106049.

25. Nathaneal Johnson. “Do industrial agricultural methods actually yield more food per acre than organic ones?” Grist, October 14, 2015. [online]. grist.org/food/do-industrial-agricultural-methods-actually-yield-more-food-per-acre-than-organic-ones/.

26. US Environmental Protection Agency. “Nutrient Pollution: The Problem.” [online]. epa.gov/nutrientpollution/problem.

27. Charles R. Fink et al. “Nitrogen fertilizer: Retrospect and prospect.” Publications of the National Academy of Sciences 96(4) (1999). [online]. doi:0.1073/pnas.96.4.1175.

28. Robert W. Howarth. “Coastal nitrogen pollution: A review of sources and trends globally and regionally.” Harmful Algae 8(1) (2008). [online]. dx.doi.org/10.1016/j.hal.2008.08.015.

29. Matthew Hora and Judy Tick. From Farm to Table: Making the Connection in the Mid-Atlantic Food System. Capital Area Food Bank of Washington DC, 2001. [online]. openlibrary.org/books/OL11779852M/From_farm_to_table.

30. Joan Dye Gussow. Chicken Little, tomato sauce and agriculture: Who will produce tomorrow’s food? The Bootstrap Press, 1991. [online]. worldcat.org/title/chicken-little-tomato-sauce-and-agriculture-who-will-produce-tomorrows-food/oclc/23583327. This energy ratio has been growing, so today’s ratio is likely to be significantly higher.

31. Ibid.

32. Data from the IMFund, PFOOD, and PNRG price indices: International Monetary Fund. “IMF Primary Commodity Prices.” [online]. imf.org/external/np/res/commod/index.aspx.

33. Suppose you have a male and a female mouse in a large cage with water and everything else mice need to be happy. Every morning, you give the mice a pound of food; every evening, you remove the leftover food. The mice have babies, the babies have babies, and the population grows. Eventually the population reaches a certain number of mice, call it N (the carrying capacity, in this case the number of mice that a pound of food per day can support), and over time you observe that it stays pretty close to that same number. You also notice that the mice eat all the food by the end of the day. The population has reached equilibrium. What happens if you double the food? The population will climb until there are 2N mice and settle at that new equilibrium. The Green Revolution is evidence that human populations also follow this basic law of ecology. See: R. L. Strecker and J. T. Emlen. “Regulatory mechanisms in house-mouse populations: The effect of limited food supply on a confined population.” Ecology 34(2) (1953). [online]. doi:10.2307/1930903.

Interestingly, the mouse population will stop growing very suddenly because the mice abruptly stop reproducing when they reach carrying capacity. The biological mechanism for this involves physiological changes to their reproductive organs.

34. Relative to demand in the year 2000: Green. “Farming and the fate of wild nature.”

35. UN FAO. “The State of Food Insecurity in the World.” 2009 and 2015 reports. [online]. ao.org/hunger/en/. Note that the FAO has been accused of revising past estimates in order to demonstrate positive progress on world hunger: see Martín Caparrós. “Counting the hungry.” New York Times, September 27, 2014. [online]. nytimes.com/2014/09/28/opinion/sunday/counting-the-hungry.html.

36. Patricio Grassini et al. “Distinguishing between yield advances and yield plateaus in historical crop production trends.” Nature Communications 4 (2013). [online]. doi:10.1038/ncomms3918.

37. See e.g., Prabhu L. Pingali. “Green Revolution: Impacts, limits, and the path ahead.” Publications of the National Academy of Sciences 109(31) (2012). [online]. doi:10.1073/pnas.0912953109.

38. Michael P. Russelle et al. “Reconsidering Integrated Crop: Livestock Systems in North America.” Agronomy Journal 99(2) (2006). [online]. doi:10.2134/agronj2006.0139.

39. Brenda B. Lin. “Resilience in Agriculture through Crop Diversification: Adaptive Management for Environmental Change.” BioScience 61(3) (2011). [online]. doi:10.1525/bio.2011.61.3.4.

40. My favorite anecdote about the modern reduction in crop bio-diversity is told by Jon Jondai. See his short video talk: John Jandai. “A personal story on seed saving.” YouTube, 2011. [online]. youtube.com/watch?v=3BweruD8RyI.

41. Tom Gleeson et al. “Water balance of global aquifers revealed by groundwater footprint.” Nature 488 (2012). [online]. doi:10.1038/nature11295.

42. David R. Steward et al. “Tapping unsustainable groundwater stores for agricultural production in the High Plains Aquifer of Kansas, projections to 2110.” Publications of the National Academy of Sciences 110(37) (2013). [online]. doi:10.1073/pnas.1220351110.

43. This could be seen as an opportunity. For example, we could choose to let the Ogallala grassland return to native prairie with grazing bison. Meriwether Lewis recorded his impression of the bison on numerous occasions in his journal. For example, on September 17, 1804, bound toward the Pacific in the land that is now South Dakota, he wrote, “This senery already rich pleasing and beautiful was still farther hightened by immence herds of Buffaloe deer Elk and Antelopes which we saw in every direction feeding on the hills and plains.” On the way back, on August 29, 1806, he wrote, “I assended to the high Country.... From this eminance I had a view of a greater number of buffalow than I had ever Seen before at one time. I must have Seen near 20,000 of those animals feeding on this plain.” Source: Discovering Lewis and Clark website. “Bison in the Journals.” [online]. lewis-clark.org/article/443.

This native system of production requires no fossil water, fossil fuels, chemicals, tilling, or indeed human interventions of any kind. Considering that this system was fine-tuned by nature over evolutionary time, and given the anecdotal reports of pre-agricultural abundance, it’s possible that the prairie/bison system could yield more meat per acre than our current corn/cattle system, although there has been little research into this question. Ideally vast swaths of grassland would be returned to the commons, owned by all. Implementing this ideal version of the vison would require transforming some of society’s deepest tenets about agriculture and land ownership. However, if productivity and profitability of the prairie/bison system were indeed higher than the corn/cattle system in certain ecosystems, a middle path would be possible. Consideration of these systems should include fixing cost externalities in fossil fuel and fossil water that effectively subsidize the corn/cattle system.

44. Predicted in the medium warming scenario presented in California Climate Change Center. Our Changing Climate: Assessing the Risks to California. Document # CEC-500-2006-077, 2006. [online]. meteora.ucsd.edu/cap/pdffiles/CA_climate_Scenarios.pdf.

45. Benjamin I. Cook et al. “Unprecedented 21st century drought risk in the American Southwest and Central Plains.” Science Advances 1(1) (2015). [online]. doi:10.1126/sciadv.1400082. This paper predicts that droughts will get worse even if humans choose to mitigate global warming, but they will be worse still if we choose not to.

46. UN FAO. The State of the World’s Land and Water Resources for Food and Agriculture: Managing Systems at Risk.” FAO Summary Report, 2011. [online]. fao.org/nr/water/docs/SOLAW_EX_SUMM_WEB_EN.pdf.

47. Nigel Hunt and Sarah McFarlane. “‘Peak soil’ threatens future global food security.” Reuters, July 17, 2014. [online]. reuters.com/ article/us-peaksoil-agriculture-idUSKBN0FM1HC20140717. The article cites a 30% yield decrease by 2050, and attributes this prediction to John Crawford, a soil scientist affiliated with Rothamsted Research.

48. “In just one teaspoon of agricultural soil there can be one hundred million to one billion bacteria, six to nine feet of fungal strands put end to end, several thousand flagellates and amoeba, one to several hundred ciliates, hundreds of nematodes, up to one hundred tiny soil insects, and five or more earthworms. These organisms are essential for healthy growth of your plants.” S. Tianna DuPont. Soil quality: Introduction to soils. Penn State College Extension, 2012, p. 6. [online]. extension.psu.edu/business/start-farming/soils-and-soil-management/soil-quality/extension_publication_file.

49. John W. Crawford et al. “Microbial diversity affects self-organization of the soil-microbe system with consequences for function.” Journal of the Royal Society Interface 9(71) (2012). [online]. doi:10.1098/rsif.2011.0679.

50. Hunt and McFarlane. “‘Peak soil.’”

51. Erica Goode. “Farmers put down the plow for more productive soil.” New York Times, March 9, 2015. Much of this no-till farming uses herbicides to kill cover crops. However, cover crops can readily be killed mechanically, making organic no-till feasible: see Rodale Institute. “Our Work: Organic No-Till.” [online]. rodaleinstitute.org/our-work/organic-no-till/.

52. Each year humans destroy 13 million hectares of forest (90,000 acres per day), most of it in tropical rainforests, but some forest regenerates; the net annual loss is 5.2 million hectares. (These figures are annual means between 2000 and 2010.) US FAO. State of the World’s Forests, 2011. Rome. [online]. fao.org/docrep/013/i2000e/i2000e00.htm.

53. IPCC AR5 WG2, Chapter 7.

54. David B. Lobell and Christopher B. Field. “Global scale climate-crop yield relationships and the impacts of recent warming.” Environmental Research Letters 2(1) (2007). [online]. doi:10.1088/1748-9326/2/1/014002.

55. Andrew E. Kramer. “Russia, crippled by drought, bans grain exports.” New York Times, August 5, 2010. [online]. nytimes.com/2010/08/06/world/europe/06russia.html.

56. Koh Iba. “Acclimative response to temperature stress in higher plants: Approaches of gene engineering for temperature tolerance.” Annual Review of Plant Biology 53 (2001). doi:10.1146/annurev.arplant.53.100201.160729.

57. Daniel P. Bebber et al. “Crop pests and pathogens move polewards in a warming world.” Nature Climate Change 3 (2013). [online]. doi:10.1038/nclimate1990.

58. Samuel S. Myers et al. “Increasing CO₂ threatens human nutrition.” Nature 510 (2014). [online]. doi:10.1038/nature13179.

59. Lewis H. Ziska et al. “Rising atmospheric CO₂ is reducing the protein concentration of a floral pollen source essential for North American bees.” Proceedings of the Royal Society B 283(1828) (2016). [online]. doi:10.1098/rspb.2016.0414.

60. Linda O. Mearns et al. “Effect of changes in interannual climatic variability on CERES-wheat yields: Sensitivity and 2xCO₂ general circulation model studies.” Agricultural and Forest Meteorology 62(3&4) (1992). [online]. doi:10.1016/0168-1923(92)90013-T.

61. Stephen P. Long et al. “Food for thought: Lower-than-expected crop yield stimulation with rising CO₂ concentrations,” Science 312 (2006). [online]. doi:10.1126/science.1114722.

62. Ibid.

63. H. Charles J. Godfray. et al. “Food security: The challenge of feeding 9 billion people.” Science 327 (2010). [online]. doi:0.1126/science.1185383.

64. Deepak K. Ray et al. “Yield Trends Are Insufficient to Double Global Crop Production by 2050.” PLOS One 8(6) (2013). [online]. doi:10.1371/journal.pone.0066428.

65. Rabah Arezki and Markus Brückner. “Food prices and political instability.” International Monetary Fund Working Paper #WP/11/62, 2011. [online]. imf.org/external/pubs/ft/wp/2011/wp1162.pdf.

66. Ben Laffin and Megan Specia. “Venezuela Gripped by Hunger and Riots.” New York Times Video, June 21, 2016. [online]. nytimes.com/video/world/americas/100000004485562/venezuela-gripped-by-hunger-and-riots.html.

67. McGlade and Ekins. “The geographical distribution of fossil fuels,” p. 190.

68. Donald W. Jones et al. “Oil price shocks and the macroeconomy: What has been learned since 1996.” Energy Journal 25(2) (2004). [online]. doi:10.2307/41323029.

69. Kevin Drum. “Peak oil and the great recession.” Mother Jones, October 19, 2011. [online]. motherjones.com/kevin-drum/2011/10/peak-oil-and-great-recession.

70. Art Berman. “Despite OPEC production cut, another year of low oil prices is likely.” Forbes, January 9, 2017. [online]. forbes.com/sites/arthurberman/2017/01/09/the-opec-oil-production-cut-another-year-of-lower-oil-prices.

71. You can see them for yourself in satellite images on an online map tool. For example, enter the coordinates “40N, 109.33W” in the search bar, and switch to the satellite view. Those strangely repetitive structures are fracking wells. Now hold on to your seat, and zoom out a few times: welcome to the Matrix. There are many similar areas in other parts of the US.

72. Data: US Energy Information Administration. “U.S. Field Production of Crude Oil” and “Total Petroleum and Other Liquids Production.” [online]. eia.gov.

73. A consequence of the aggregation of many individual wells and the central limit theorem from statistics.

74. The functional form for the sum of two Hubbert curves is:

75. J. David Hughes. Drilling deeper: A reality check on U.S. government forecasts for a lasting tight oil and shale gas boom. Post Carbon Institute, October 2014. [online]. postcarbon.org/wp-content/uploads/2014/10/Drilling-Deeper_FULL.pdf. At the time of writing, this was the most thorough report available; however, some might claim that the Post Carbon Institute is biased towards predicting an early peak.

76. US Energy Information Administration. U.S. Crude Oil Production to 2025: Updated Projection of Crude Types. May 25, 2015, p. 1. [online]. eia.gov/analysis/petroleum/crudetypes/pdf/crudetypes.pdf.

77. G. Maggio and G. Cacciola. “When will oil, natural gas, and coal peak?” Fuel 98 (2012). [online]. doi:10.1016/j.fuel.2012.03.021.

78. Cutler J. Cleveland. “Energy and the US economy: A biophysical perspective.” Science 225(4665) (1984). [online]. doi:10.1126/science.225.4665.890.

79. Nathan Gagnon et al. “A preliminary investigation of the energy return on energy investment for global oil and gas production.” Energies 2(3) (2009). [online]. doi:10.3390/en20300490.

80. Charles A.S. Hall et al. “EROI of different fuels and the implications for society.” Energy Policy 64 (January 2014). [online]. doi:10.1016/j.enpol.2013.05.049.

81. Ibid.

82. Ibid. and references contained therein. Note that it’s difficult to make EROEI estimates, and I’ve rounded the published values to one significant figure to reflect this uncertainty (Hall “EROI of different fuels” does not provide uncertainty estimates).

83. Mean world GDP growth rates for the 1960s, 1970s, 1980s, 1990s, 2000s, and 2010 to 2015 were 5.52%, 4.11%, 3.07%, 2.66%, 2.86%, and 2.95%. Mean US GDP growth rates for the same periods were 4.66%, 3.54%, 3.14%, 3.23%, 1.82%, and 2.17%. Data from: World Bank. “GDP Growth (annual %)” [online]. data.worldbank.org/indicator/NY.GDP.MKTP.KD.ZG.

84. For example, section 309a of the California Corporations Code states: “A director shall perform the duties of a director...in good faith, in a manner such director believes to be in the best interests of the corporation and its shareholders.” [online]. codes.findlaw.com/ca/corporations-code/corp-sect-309.html. Your jurisdiction no doubt has a similar statute.

85. Citizens United v. Federal Election Commission. 558 U.S. 310 (2010). [online]. supremecourt.gov/opinions/09pdf/08-205.pdf.

86. American Legislative Exchange Council. [online]. alec.org.

87. Fortune. Global 500. [online]. fortune.com/global500/2015/. Among the ten largest corporations in 2015, six of the top ten rankings were held by petroleum companies; two other spots in the top ten were held by automotive companies.

88. Naomi Oreskes and Erik Conway. Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming. Bloomsbury, 2010.

89. The United Nations Framework Convention on Climate Change. Article 3: Principles. [online]. unfccc.int/cop4/conv/conv_005.htm.

90. Money Network Alliance. “The money system requires continual growth.” [online]. monneta.org/en/the-money-system-requires-continual-growth/.

91. First, increasing the efficiency of our production systems and gadgets can only take us so far: even a perfectly efficient microwave oven (or replicator, for that matter) still needs to source at least 240 grams of clean water and 80,000 Joules of energy for that cup of tea (Earl Grey, hot). And if real economic growth were to somehow continue exponentially while energy and resource use remain fixed, after a few doublings of the economy, we’d reach an absurdity in which all the resources and energy in the world could be purchased with a single worker’s daily wage. For the full reductio ad absurdum argument against decoupling, see Tom Murphy. “Can Economic Growth Last?” Do the Math blog, July 14, 2011. [online]. physics.ucsd.edu/do-the-math /2011/07/can-economic-growth-last/.

92. According to the World Wildlife Fund, populations of vertebrate species have dropped by 52% on average since 1970: World Wildlife Fund. Living Planet Report 2014. [online]. worldwildlife.org/pages/living-planet-report-2014.

93. Jurriaan M. De Vos et al. “Estimating the normal background rate of species extinction.” Conservation Biology 29 (2015). [online]. doi:10.1111/cobi.12380.

94. Vaclav Smil. The Earth’s Biosphere: Evolution, Dynamics, and Change. MIT Press, 2003. According to this source, human flesh accounts for 26% of the land vertebrate biomass total, while livestock flesh accounts for 71%. Note that these numbers are based on data from 1990 or earlier, when there were far fewer humans and far more wild animals, so today’s situation is most probably even more unbalanced.

95. Brian MacQuarrie. “Ticks devastate Maine, N.H. moose populations.” Boston Globe, January 13, 2017. [online]. bostonglobe.com/metro/2017/01/13/winter-ticks-exact-heavy-toll-new-england-moose/PmpQ3QAHm9C1imAxkzMhDM/story.html.

96. Alejandro Estrada et al. “Impending extinction crisis of the world’s primates: Why primates matter.” Science Advances 3(1) (2017). [online]. doi:10.1126/sciadv.1600946.

97. Jared Diamond. Collapse: How Societies Choose to Fail or Succeed. Penguin, 2004.

98. Mathis Wackernagel et al. “Tracking the ecological overshoot of the human economy.” Publications of the National Academy of Sciences 99(14) (2002). [online]. doi:10.1073/pnas.142033699.

99. Gretchen C. Daily et al. “Optimum human population size.” Population and Environment 15(6) (1994). [online]. dieoff.org/page99.htm.

100. Christian J. Peters et al. “Carrying capacity of U.S. agricultural land: Ten diet scenarios.” Elementa: Science of the Anthropocene 4(116) (2016). [online]. doi:10.12952/journal.elementa.000116. Interestingly, according to this study, the planet could actually support more dairy-eating vegetarians than vegans, because dairy animals can eat grass in regions too arid to farm.

101. UN Food and Agriculture Organization. “Key facts on food loss and waste you should know!” [online]. fao.org/save-food/resources/keyfindings/en/.

102. Jared Diamond. “The worst mistake in the history of the human race.” Discover Magazine, May 1987. [online]. discovermagazine.com/1987/may/02-the-worst-mistake-in-the-history-of-the-human-race. Diamond provides evidence that the following miseries resulted from switching to agriculture some 10,000 years ago: extended work hours; class systems; oppression of women; increased incidence of parasites and disease; increased risk of famine; malnutrition; and increased warfare. One could argue that agriculture also led to chattel slavery, and in Chapter 5, I’ve argued that it has led to overpopulation and global warming, as well. And this is just from the human perspective. For most nonhuman species (rats and wheat being two exceptions), agriculture has meant nothing but death.

103. Daniel Quinn. The Story of B. Bantam Books, 1996.

Chapter 6: Our Mindset

1. The theory of evolution, which challenged the Christian creation myth, provides an example of this.

2. Roland Barthes. Mythologies, trans. Annette Lavers. Hill and Wang, 1972, pp. 142–143.

3. Meadows. “Places to Intervene in a system.”

4. By “we” I mean those of us operating through the myth of progress. This seems to include the vast majority of people in industrial society, cutting across economic and racial strata.

5. For this image, I thank John Michael Greer, whose eye-opening blog post “Which Way to Heaven?” was an influence for this chapter: John Michael Greer. “Which Way to Heaven?” The Archdruid Report, September 25, 2013. [online]. thearchdruidreport.blogspot.ca/2013/09/which-way-to-heaven.html.

6. Such is the case with exoplanetary astronomy. There are no exoplanet deniers; or if there are, they stay pretty quiet.

7. As we saw in Chapter 3, although the estimated quantities have uncertainties (and always will), and although there are still many details to pursue, the basic existence of a human-caused global radiative energy imbalance is as clear as anything in science can be.

8. Speaking on Frontline, Dr. Arjun Srinivasan, Associate Director at the Centers for Disease Control and Prevention, said: “For a long time, there have been newspaper stories and covers of magazines that talked about ‘The end of antibiotics, question mark?’ Well, now I would say you can change the title to ‘The end of antibiotics, period.’ We’re here. We’re in the post-antibiotic era.” Sarah Childress. “Dr. Arjun Srinivasan: We’ve Reached ‘The End of Antibiotics, Period.’” Frontline, October 22, 2013. [online]. pbs.org/wgbh/frontline/article/dr-arjun-srinivasan-weve-reached-the-end-of-antibiotics-period/.

9. See Robin McKie. “Millions at risk as deadly fungal infections acquire drug resistance.” Guardian, August 27, 2016. [online]. theguardian.com/society/2016/aug/27/millions-at-risk-as-deadly-fungal-infections-acquire-drug-resistance.

10. Kenneth J. Loceya and Jay T. Lennona. “Scaling laws predict global microbial diversity.” Publications of the National Academy of Sciences 113(21) (2016). [online]. doi:10.1073/pnas.1521291113.

11. Aboriginal Culture. “Religion and Ceremony.” [online]. aboriginalculture.com.au/religion.shtml.

12. Daniel Kahneman. Thinking, Fast and Slow. Farrar, Straus & Giroux, 2013.

13. Solomon E. Asch. “Opinions and social pressure.” Scientific American 193(5) (1955). [online]. scientificamerican.com/article/opinions-and-social-pressure/.

14. Overall, subjects conformed and gave the wrong answer a shocking 37% of the time.

15. See Chapter 11 for discussion of how this habit operates at the level of physical sensation.

Chapter 7: Trailheads into the Wilderness

1. According to the US Centers for Disease Control and Prevention, depression afflicts more than 26% of the US adult population; and by 2020 will be the second leading cause of disability throughout the world, trailing only coronary heart disease: US CDC. “Mental Health Basics.” [online]. cdc.gov/mentalhealth/basics.htm. Drug overdose deaths continue to rise: US CDC. “Drug overdose deaths in the United States continue to increase in 2015.” [online]. cdc.gov/drugoverdose/epidemic/.

2. Palm oil is used in products such as buttery spreads, crackers, instant noodles, cosmetics, and soaps; it sometimes hides under other names in ingredient lists, such as stearic acid, sodium lauryl/laureth sulfate, and cetyl alcohol: Lael Goodman. “How Many Products with Palm Oil Do I Use in a Day?” Union of Concerned Scientists Blog, April 3, 2014. [online]. blog.ucsusa.org/lael-goodman/how-many-products-with-palm-oil-do-i-use-in-a-day. Half of all packaged products in the supermarket: Rosie Spinks. “Why does palm oil still dominate the supermarket shelves?” The Guardian, December 17, 2014. [online]. theguardian.com/sustainable-business/2014/dec/17/palm-oil-sustainability-developing-countries.

Sustainability of palm oil is a complicated question: on a given patch of land, you can either have rainforest or oil palms, but not both. But this is true of other crops in other biomes, as well.

3. Vipassana Meditation. Dhamma.org. [online]. dhamma.org

4. Citizens’ Climate Lobby is an international volunteer organization dedicated to creating political will for real climate action. [online]. citizensclimatelobby.org.

Chapter 8: Like to Bike

1. At that time, we still made a Christmas pilgrimage to Illinois, loading the family onto an airplane every year. We’ve stopped doing this and are no worse off; see Chapter 10.

2. Notes from a recent long ride to an event on the other side of Los Angeles: “I could have taken public transit, but I didn’t want to miss the bike ride. It was powerful—I felt powerful. Thought it was out of my comfort zone a little but then realized it was well within. And I made all these connections. To places I’d driven to. To the layout of the city. To the city’s efforts to make better bike paths. To the neighborhoods. To the sky. To my own amazing body. It felt really good, in my body. Also in my mind and my spirit.”

3. Worse car commutes are correlated with higher divorce rates. Annie Lowrey. “Your Commute Is Killing You.” May 26, 2011, slate.com. [online]. slate.com/articles/business/moneybox/2011/05/your_commute_is_killing_you.html.

4. Scientific source: Ingrid J.M. Hendriksen et al. “The association between commuter cycling and sickness absence.” Preventive Medicine 51(2) (2010). [online]. doi:10.1016/j.ypmed.2010.05.007.

Anecdotal source: For several years before I started biking, I suffered through a series of sinus infections, about one per year. Since getting back on my bike in 2009, I’ve only had one (during a period when I was biking less), and I’ve hardly been sick at all. Biking makes me feel generally great.

5. Biking saves our family more than $2,000 per year at the 2016 IRS mileage rate of $0.54 per mile, after accounting for the $150 or so per year we spend on bike maintenance. This presumes that one bike mile ridden replaces one car mile ridden (it actually replaces more, because on a bike I plan my trips carefully), and it doesn’t include indirect savings such as not needing a gym membership or seldom getting sick.

6. For every hour I spend keeping my bike in good shape, I likely spend 20 or more keeping my old car, Maeby, growling along. Maeby is much more complex, and can break in many more ways.

7. Herb Weisbaum. “What’s the life expectancy of my car?” NBC News, March 28, 2006. [online]. nbcnews.com/id/12040753/ns/business-consumer_news/t/whats-life-expectancy-my-car/.

8. Errands on bikes are bound to be local, simply because it requires an investment of personal energy.

9. For example, shifting from a car commute to a bike commute.

10. Jeroen Johan de Hartog et al. “Do the health benefits of cycling outweigh the risks?” Environmental Health Perspectives 118 (2010). doi:10.1289/ehp.0901747. Estimates are based on life table calculations applied to a population of 500,000 people aged 18–64.

Note that in a small number of extremely polluted cities, such as Delhi, India, breathing the air can outweigh the benefits of the exercise: Nick Van Mead. “Tipping point: Revealing the cities where exercise does more harm than good.” The Guardian, February 13, 2007. [online]. theguardian.com/cities/2017/feb/13/tipping-point-cities-exercise-more-harm-than-good. I find this horrifying, and a great argument for clean air policies such as carbon fee and dividend (Chapter 14).

11. How does this result translate to US roads? De Hartog et al. used 2008 accident statistics from the Netherlands, where the mortality per passenger mile (in the 20 to 70 year age group) was 4.3 times higher for biking than for driving. Unfortunately, biking is more dangerous in the US, where the mortality per passenger mile was about 7 times higher for biking than for driving (there were 11 car deaths per billion passenger miles in 2011; and 680 bicycle deaths [2011] over 9 billion bicycle miles): US DOT, Federal Highway Administration. National Household Travel Survey 2009. [online]. nhts.ornl.gov/introduction.shtml. Adjusting the factor of nine from de Hartog by the ratio 4.3/7 implies that biking in the US is only 6 times safer for one’s overall health than driving. However, de Hartog et al. analyzes bicycle trips that occur in traffic 100% of the time. But about one-half of my commute is on a bike path through a nature preserve with no traffic, and the same is true for Sharon’s commute. If this is typical, it might cut risk exposure approximately in half, bringing the overall safety factor in the US back up to about ten.

12. David Rojas-Rueda et al. “The health risks and benefits of cycling in urban environments compared with car use: Health impact assessment study.” British Medical Journal (2011). [online]. doi:10.1136/bmj.d4521. In one year in Barcelona, 182,000 residents using the bike sharing system, compared with car users, experienced annual changes in mortality of 0.03 additional deaths from road traffic incidents, 0.13 additional deaths from air pollution, but avoided 12.46 deaths due to physical activity (a benefit to risk ratio of 77).

13. In 2011, 23% of people in the US who died riding bicycles were legally drunk: US DOT, National Highway Safety Traffic Administration. “Traffic Safety Facts, 2011 Data: Bicyclists and Other Cyclists.” Doc# DOT HS 811 743 (April 2013), p. 4. [online]. crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/811743. Those who avoid drinking and riding immediately gain a large additional safety margin. I also try to avoid riding when drunk drivers are more likely to be out.

14. A disproportionate number of bicycle accidents and fatalities involve the cyclist breaking rules of the road or otherwise violating common sense. For example, a 1992 study observing bikers in Palo Alto found that 15% of cyclists rode against traffic, and their risk of an accident was 3.6 times as high as those riding with traffic: Alan Wachtel and Diana Lewiston. “Risk Factors for Bicycle-Motor Vehicle Collisions at Intersections.” Institute of Transportation Engineers Journal 64(9) (1994). [online]. bicyclinglife.com/Library/riskfactors.htm.

15. Such as getting crushed by a right-turning vehicle when a light turns green because you weren’t far forward enough or far back enough: Michael Bluejay “Ten Ways Not to Get Hit—Collision Type #5: The Red Light of Death.” Bicyclesafe website, updated May 2013. [online]. bicyclesafe.com.

16. I was unable to find reliable research quantifying the safety margin provided by a bike helmet. A simple thought experiment is enough for me: in the unlikely event that I find myself flying headfirst towards concrete, I’d want a helmet on my head. However, it’s better not to get hit in the first place.

17. Incredibly, only 15% of riders use lights at night: City of Boston. “Boston Bicycle Plan.” Boston Transportation Department, 2001, p. 14. [online]. cityofboston.gov/transportation/accessboston/pdfs/bicycle_plan.pdf. Nearly ½ of US biking deaths occur after dark without bike lights, although only maybe 3% of rides happen after dark: City of Cambridge. “Bicycling Rules of the Road.” Community Development Department, 2011. [online]. cambridgema.gov/cdd/transportation/gettingaroundcambridge/bybike/rulesoftheroad. For goodness sake, if you ride at night, use lights!

18. Some terminology of bike infrastructure: bike paths are car-free bicycle roads; bike tracks run alongside car roads but are physically separated from them; and bike lanes are space on car roads, demarcated only by a painted line, and are often situated between traffic and parked cars.

19. I restricted my counting to cars on my route, which didn’t include the thousands of additional cars I saw on the freeway that parallels part of the route.

20. Brian McKenzie. “Modes Less Traveled: Bicycling and Walking to Work in the United States: 2008–2012.” US Census Bureau (2014). [online]. census.gov/library/publications/2014/acs/acs-25.html.

21. Netherlands Ministry of Transport, Public Works and Water Management. “Bicycle Use in the Netherlands.” Cycling in the Netherlands, 2009, section 1.1. [online]. fietsberaad.nl/library/repository/bestanden/CyclingintheNetherlands2009.pdf.

22. “Over the period 2005–2007 inhabitants of Amsterdam used their bikes on average 0.87 times a day, compared to 0.84 for their cars.” CROW Fietsberaad. “Amsterdam: For the first time more transfers by bike than by car.” News article, January 22, 2009. [online]. fietsberaad.nl/index.cfm?lang=en&section=Nieuws&mode=newsArticle &news Year=2009&repository=Amsterdam:+for+the+first+time +more +transfers+by+bike+than+by+car.

23. In the US, these priorities are baked into the metric that state departments of transportation use to design and evaluate roadways: Level of Service (LOS) means the rate of cars passing through an inter section.

24. Peter L. Jacobsen. “Safety in numbers: More walkers and bicyclists, safer walking and bicycling.” Injury Prevention 9 (2003). [online]. doi:10.1136/ip.9.3.205. This study was prompted by the Pasadena City Council in 1998 (which I naturally find interesting). The evidence for the safety in numbers effect is overwhelming, and there are many other studies.

25. At 11.3 kg CO₂ per gallon, which include upstream emissions; see Chapter 9.

26. See Constantine Samaras and Kyle Meisterling. “Life Cycle Assessment of Greenhouse Gas Emissions from Plug-in Hybrid Vehicles: Implications for Policy.” Environmental Science & Technology 42(9) (2008). Supporting information. [online]. doi:10.1021/es702178s; Mike Berners-Lee and Duncan Clark. “What’s the carbon footprint of...a new car?” Guardian Green Living blog, September 23, 2010. [online]. theguardian.com/environment/green-living-blog/2010/sep/23/carbon-footprint-new-car.

27. Jay Schwartz. “Calories burned biking one mile.” Livestrong.com, November 2, 2013. [online]. livestrong.com/article/135430-calories-burned-biking-one-mile/. Yes, this does mean that Tour de France riders eat about four times as much as the spectators watching them.

28. This assumes 3,800 kcal of produced food and 2,100 kcal of consumed food per day, the difference being wasted food.

29. Using a ratio of typical car and bike weights, and assuming a 40,000-mile bike lifetime.

30. Considering only the embodied impact in the bike.

31. Michael Bluejay. “How to Not Get Hit by Cars: Important Lessons in Bicycle Safety.” Bicycle Safe, May 2013. [online]. bicyclesafe.com.

32. Kurt Holzer. “Bike Law attorney Kurt Holzer makes a compelling case for the ‘Idaho Stop.’” Bikelaw.com blog, January 27, 2016. [online]. bikelaw.com/2016/01/27/living-with-stop-as-yield-for-cyclists/.

Chapter 9: Leaving Fossil Fuel

1. In 2012, Bangladeshi per capita emissions were 1.2 tonnes CO₂e (1.0 tonnes CO₂e excluding land-use change), according to the World Resources Institute, CAIT Climate Data Explorer. [online]. cait.wri.org/historical.

2. There is one change I’d probably roll back, to a degree, if global warming suddenly, magically, disappeared: I’d fly occasionally, though far less than I did before I reduced. Still, overall I’ve gained more than I’ve sacrificed by giving up flying.

3. Charles Eisenstein discusses the story of separation and the importance of kindness in: Charles Eisenstein. The More Beautiful World Our Hearts Know Is Possible, 3rd ed. North Atlantic, 2013. Kindness is necessary but it’s not sufficient: we also need to rapidly reduce our greenhouse gas emissions.

4. Here, I’ll use the mass of CO₂ as opposed to the mass of carbon: 3.67 kg CO₂ contains 1 kg of carbon (the oxygen atoms add mass). In other parts of the book, I may give quantities as the mass of carbon (e.g., GtC in Chapter 3). Also, I’ll round numbers to what I think is a reasonable degree of precision. In cases where I don’t give uncertainty explicitly, the uncertainty estimate can be inferred from the numerical precision. For example, 120 implies more uncertainty (roughly 10%) than 121 (roughly 1%). However, I reserve the right to give an extra digit of precision if I feel that omitting it would bias a comparison or calculation.

Be aware that various analyses of greenhouse gas emissions use different methods and make different assumptions. Be careful to assess the assumptions underlying any given analysis. If these assumptions aren’t clear, or if the underlying methodology or sources of information aren’t clear, be wary of the conclusions.

5. Upstream emissions add an additional 28% [24%–31%] for gasoline, 20% [15%–25%] for diesel, 21% [17%–24%] for jet fuel, and 15% [9%–20%] for natural gas. See US EPA Greenhouse Gas Emissions from the U.S. Transportation Sector: 1990–2003. Office of Transportation and Air Quality, 2006, Table 14.1. [online]. nepis.epa.gov. These upstream emission estimates only consider CO₂ emissions; we will see below that methane emissions from natural gas production are also significant.

6. NO and NO2 which form ozone, a greenhouse gas, in the upper troposphere.

7. The mean of the IPCC’s estimates of the European average emission rate (short haul) and the rate for a 747 with 70% occupancy average over a 7,500-mile trip (long haul) is 0.30 kg CO₂ per coach passenger mile. However, the mean of the EPA’s estimates for long and short flights is 0.21 kg CO₂ per coach passenger mile. I average the IPCC and EPA estimates and then factor in upstream emissions of 21%.

8. David J. Unger. “First-class ticket: More legroom, more emissions.” Christian Science Monitor, June 17, 2013. [online]. csmonitor.com/Environment/Energy-Voices/2013/0617/First-class-ticket-more-legroom-more-emissions.

9. Christian Azar and Daniel J. A. Johansson. “Valuing the non-CO₂ climate impacts of aviation.” Climatic Change 111 (2012). doi:10.1007/s10584-011-0168-8.

10. Worldwatch Institute. Vital Signs 2006–2007: The Trends That Are Shaping Our Future. Norton, 2006, p. 68.

11. Or 2,500 kg CO₂e if we include non-CO₂ effects (via a multiplicative factor of 2.5).

12. Domestic and international carriers at all US airports tallied 1.3 trillion revenue passenger miles in 2015: US DOT, Bureau of Transportation Statistics. “Passengers—All Carriers—All Airports.” [online]. transtats.bts.gov/Data_Elements.aspx?Data=1. US population in 2015: 321 million: US census. [online]. census.gov/popclock. This leads to a very rough estimate that ignores foreign travelers in the US, and US travelers in foreign countries.

13. I actually love the act of flying itself. As a boy, the National Air and Space Museum’s brilliant 1976 film To Fly! utterly captivated me. I’d make my parents take me to see it each spring during our Easter road trip to Washington, DC to visit my grandparents. During college I learned how to fly sailplanes—small high-performance planes without engines that can soar on updrafts to heights of 50,000 feet—soloing, obtaining my license, and eventually wooing Sharon with soaring flight.

14. I discuss my transition to slow travel in Chapter 10.

15. US per capita vehicle miles of travel in 2013 was 9,400 miles: Chris McCahill. “Per capita VMT drops for ninth straight year: DOTs taking notice.” State Smart Transportation Initiative, February 24 2014. [online]. ssti.us/2014/02/vmt-drops-ninth-year-dots-taking-notice/. The average fuel economy of cars on the road in 2013 was 21.6 miles per gallon: US DOT. “Average Fuel Efficiency of U.S. Light Duty Vehicles.” Bureau of Transportation Statistics, Table 4-23. [online]. ita.dot.gov/bts/sites/rita.dot.gov.bts/files/publications/national_transportation_statistics/html/table_04_23.html.

16. This term originated in her poem, “Leave.”

17. Burning a gallon of gas or diesel releases 8.9 and 10.2 kg CO₂, respectively: US Energy Information Agency. “Voluntary Reporting of Greenhouse Gases Program Fuel Emission Coefficients,” Table 2. [online]. eia.gov/oiaf/1605/coefficients.html#tbl2. I’ve then added upstream emissions of 28% for gasoline and 20% for diesel (these are 2015 values; upstream emissions may increase over time).

18. The industrial agricultural processes used to grow this crop do result in fossil emissions (that is, CO₂ molecules made from carbon that had previously been locked safely underground). However, because I’m using a waste product, I don’t count these emissions.

19. To calculate this figure: my commute was 6 miles each way, and at first, I rode it on a 35-mpg motorcycle.

20. Patrick McGeehan et al. “Beneath cities, a decaying tangle of gas pipes.” New York Times, March 23, 2014. [online]. nytimes.com/2014/03/24/nyregion/beneath-cities-a-decaying-tangle-of-gas-pipes.html.

21. The composition of raw natural gas varies among gas fields, ranging between 70% to 90% methane, with the bulk of the remainder being ethane (an insignificant contributor to global warming), rounded out by small amounts of propane, butane, nitrogen, helium, CO₂, and various impurities. Refined natural gas—the gas delivered to your home—is nearly 100% methane: Natural Gas Supply Association. “Natural Gas: Background.” [online]. naturalgas.org/overview/background.

22. Drew T. Shindell et al. “Improved attribution of climate forcing to emissions.” Science 326 (2009) [online]. doi:10.1126/science.1174760. The uncertainty in these global warming potentials is 23%. Methane traps outgoing longwave radiation much more effectively than CO₂, but remains in the atmosphere for a shorter time. Therefore, comparing to CO₂ requires picking a time horizon. For more detail, see Chapter 3.

23. Most analyses underestimate methane by using a global warming potential of only 25 (choosing the 100-year time horizon and an outdated estimate of methane’s impact). The choice of time horizon is subjective; I choose to use the average of the two conventional time horizons to avoid bias.

24. To estimate this: burning one therm of natural gas emits 5.3 kg CO₂, and burning an energy-equivalent amount of coal emits 10 kg CO₂. At a GWP of 65, 72 grams of methane has a climate impact equivalent to the difference, 4.7 kg CO₂. But the methane in a therm of natural gas has a mass of 2 kg, and 0.072 kg/2 kg = 3.6%.

25. Robert W. Howarth et al. “Methane and the greenhouse-gas footprint of natural gas from shale formations.” Climatic Change 106 (2011). [online]. doi:10.1007/s10584-011-0061-5.

26. Anna Karion et al. “Methane emissions estimate from airborne measurements over a western United States natural gas field.” Geophysical Research Letter 40 (2013). [online]. doi:10.1002/grl.50811.

27. Interstate Natural Gas Association of America (INGAA). “Pipeline Fun Facts.” Natural Gas Facts, INGAA website. [online]. ingaa.org/Topics/Pipelines101/PipelineFunFacts.aspx.

28. Here’s how I estimated this. Roughly half of the natural gas production in the US comes from unconventional gas, most of which is recovered via fracking: American Petroleum Institute. “Facts About Shale Gas.” [online]. api.org/oil-and-natural-gas/wells-to-consumer/exploration-and-production/hydraulic-fracturing/facts-about-shale-gas. So I estimate a total methane leakage rate of 5%. One kg of CH₄ combusts into 2.75 kg of CO₂; from this we can estimate that the methane in one therm of natural gas weighs about 2 kg; the 5% leakage amounts to 100 grams. At a GWP of 65 times CO₂, this comes to 6.5 kg CO₂e per therm.

29. Residential natural gas use in the US in 2014 was 5.1 trillion cubic feet (52 billion therms): US Energy Information Administration. “Natural Gas Consumption by End Use.” [online]. eia.gov/dnav/ng/ng_cons_sum_dcu_nus_a.htm.

30. A typical household of four would realize a natural gas reduction of about three tonnes CO₂e per year by installing a solar hot water heater.

The average four-person household in the US uses about 70 gallons of hot water per day: Danny S. Parker et al. “Estimating Daily Domestic Hot-Water Use in North American Homes.” ASHRAE Transactions 121(2) (2015). [online]. fsec.ucf.edu/en/publications/pdf/FSEC-PF-464-15.pdf.

Heating this water requires about 230 therms of gas per year, assuming an efficient water heater (efficiency factor of 0.71): US Office of Energy Efficiency and Renewable Energy. “Energy Cost Calculator for Electric and Gas Water Heaters.” [online]. energy.gov/eere/femp/energy-cost-calculator-electric-and-gas-water-heaters-0. Burning 230 therms of gas emits 3,000 kg CO₂e. Hot water energy use depends on climate as well as personal habits.

31. The system price tag was actually $9,000, but I received a $3,500 rebate from California and a 30% federal tax credit on the remainder. This seems like a lot of money just for hot water! Part of the problem is that the smallest available system was twice as big as what my family needs; it had an 80-gallon tank, whereas we’d been perfectly happy with a 40-gallon tank. It’s also more complicated than necessary; it uses a pump, whereas a thermosiphon would be simpler. Perhaps there’s commercial potential for a 40-gallon (or even 20-gallon) thermo siphon system. I looked into designing and building a DIY system, but it’s quite difficult and I didn’t have time.

32. Recall from Chapter 3 that N₂O is a powerful greenhouse gas. The GWP₂₀ (global warming potential on a 20-year horizon) of 1 kg of N₂O is 270 kg CO₂e.

33. The majority of this, over 80%, comes from agricultural production itself; the rest comes from such things as transportation, processing, and packaging: Natasha Gilbert. “One-third of our greenhouse gas emissions come from agriculture.” Nature News, October 31 2012. [online]. doi:10.1038/nature.2012.11708.

34. P. J. Gerber et al. Tackling climate change through livestock: A global assessment of emissions and mitigation opportunities. UN FAO, 2013. [online]. fao.org/docrep/018/i3437e/i3437e.pdf. (Note that the claim made by the documentary film Cowspiracy, that 51% of global emissions are from livestock, is incorrect.)

35. Peter Scarborough et al. “Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK.” Climatic Change 125(2) (2014). [online]. doi:10.1007/s10584-014-1169-1. A full ⅓ of food produced in the US is wasted, and these numbers include that waste. However, they assume a methane GWP of 25 and are therefore likely on the low side.

36. The Vegetarian Resource Group. “2016 National Poll.” [online]. vrg.org/nutshell/Polls/2016_adults_veg.htm.

37. This 1,000 kg CO₂e does not include the methane emissions that I’m preventing by keeping this food out of the landfill, which amounts to an additional 1,000 kg CO₂e.

38. In 2014, the total US generation was 4.1e12 kWh, with coal and natural gas generating 39% and 27% respectively (the rest was nuclear, hydro, and renewables): US Energy Information Administration. “Electric Power Monthly.” [online]. eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_1_1. This required 854 million short tons of coal and 88 billion therms of natural gas: US EIA. “Electric Power Monthly.” Data for December 2015, February 2016, full report, tables 2.1.A and 2.4.A. [online]. eia.gov/electricity/monthly.

Since a therm of natural gas produces 12.6 kg CO₂e (includes upstream emissions and leakage), burning natural gas for electricity in 2014 produced 1.1 trillion kg CO₂e. The mean emissions from burning a short ton of coal is about 2,640 kg CO₂: US EIA. Carbon Dioxide Emission Factors for Coal.” [online]. eia.gov/coal/production/quarterly/co2_article/co2.html; this value was for 1992, and I apply an 8% upstream emissions factor to get 2860 kg CO₂e per short ton: Paulina Jaramillo et al. “Comparative Life-Cycle Air Emissions of Coal, Domestic Natural Gas, LNG, and SNG for Electricity Generation.” Environmental Science and Technology 41(17) (2007). [online]. doi:10.1021/es063031o. Burning coal for electricity in the US in 2014 thus generated 2.4 trillion kg CO₂e. Dividing the total emissions (3.5e12 kg CO₂e) by the total generated (4.1e12 kWh) and factoring in 6% transmission loss yields 0.9 kg CO₂e per kWh: US EIA FAQ. “How much electricity is lost in transmission and distribution in the United States?” [online]. eia.gov/tools/faqs/faq.cfm?id=105&t=3.

39. In 2015, the average US household used 10,812 kWh: US EIA FAQ. “How much electricity does an American home use?” [online]. eia.gov/tools/faqs/faq.cfm?id=97&t=3. There are 2.5 people per US household: US Census Bureau, “Families and living arrangements,” Table HH-6. Average Population Per Household and Family: 1940 to Present. [online]. census.gov/hhes/families/data/households.html.

40. It costs an additional 3.5 cents per kWh.

41. Renewable electricity will soon be cheaper than fossil-fueled electricity, but as I’ve explained, this hasn’t occurred yet for our household. Two things that will accelerate this important transition are a revenue-neutral carbon fee (Chapter 14) and community choice aggregation (Chapter 15).

42. Lindsay Wilson. “Shrink your product footprint.” [online]. shrinkthat footprint.com/shrink-your-product-footprint. To test this, consider the Prius, which according to a detailed life cycle analysis embodies 9,000 kg CO₂e: Samaras and Meisterling. “Life Cycle Assessment of Greenhouse Gas Emissions from Plug-in Hybrid Vehicles.” Since a new Prius costs about $24,000, its embodied emissions are about 0.4 kg CO₂e per dollar—roughly equivalent to the rule of thumb.

43. In a year, the average American spends $2,200, $1,600, and $600 on home furnishings (including things such as towels and computers), clothes, and personal care products, respectively: ValuePenguin.com. “Average Household Budget in the US.” [online]. valuepenguin.com/average-household-budget. The same person spends $1,900 in one year toward buying a new car (see the next note). The total is $6,300.

44. To estimate that, on average, people in the US spend $1,900 per year on new cars:

a) 17.5 million cars and light trucks were sold in the US in 2015: Mike Spector et al. “U.S. Car Sales Set Record in 2015.” Wall Street Journal, January 5, 2016. [online]. wsj.com/articles/u-s-car-sales-poised-for-their-best-month-ever-1451999939.

b) The average price of a vehicle was about $34,000: Douglas A. McIntyre. “GM Able to Raise Average Car Price by 8%.” 24/7WallSt website, February 3, 2015. [online]. 247wallst.com/autos/2015/02/03/gm-able-to-raise-average-car-price-by-8/.

c) The US population was 320 million in 2015: Robert Schlesinger. “The 2015 U.S. and World Populations.” US News and World Report, December 31, 2014. [online]. usnews.com/opinion/blogs/robert-schlesinger/2014/12/31/us-population-2015–320-million-and-world-population-72-billion.

45. Mike Berners-Lee. “What’s the carbon footprint of...building a house.” Guardian, October 14, 2010. [online]. theguardian.com/environment/green-living-blog/2010/oct/14/carbon-footprint-house. Note that our rule of thumb would suggest a price of $160,000 for this house, not including the price of the land, but our rule of thumb can’t account for large variations in regional real estate markets.

46. The garbage you and I throw away is known as municipal solid waste (MSW). Interestingly, for every tonne of MSW thrown out in the US, there are 40 tonnes of waste created upstream. Ninety-four percent of US waste is industrial (discards from manufacturing, mining, metals processing, fossil fuel procurement, and agriculture), 3.5% is from construction and demolition, and 2.5% is MSW: Annie Leonard. The Story of Stuff: The Impact of Overconsumption on the Planet, Our Communities, and Our Health—And How We Can Make It Better. Free Press, 2011, p. 186.

47. In 2014, landfills in the US generated 6.6 billion kg of methane: US EPA. “Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990– 2014.” Table 7-2. [online]. epa.gov/sites/production/files/2016-04/documents/us-ghg-inventory-2016-chapter-7-waste.pdf. Multiplying by our mean GWP of 65 and dividing by 320 million Americans yields 1,300 kg CO₂e per person. Of our organic waste, 35% is food waste (500 kg CO₂e), 25% is wood pulp (300 kg CO₂e), 25% is textiles (300 kg CO₂e), and 15% is yard waste (200 kg CO₂e): Percentages calculated from ibid., Table 7-6.

48. World Resources Institute. CAIT Climate Data Explorer.

49. In 2000, producing the electricity to run US sewage treatment plants emitted 15.5 megatonnes of CO₂e: Center for Sustainable Systems. “U.S. Wastewater Treatment Factsheet.” University of Michigan Pub No. CSS04-14, 2016. [online]. css.snre.umich.edu/sites/default/files/U.S._Wastewater_Treatment_Factsheet_CSS04-14.pdf. Public waste water treatment plants in the US emitted an additional 38 megatonnes CO₂e from methane: EPA. “Inventory of U.S. Greenhouse Gas Emissions and Sinks”; I’ve scaled this to a methane GWP of 65. About ⅔ of sewage treatment emissions are from domestic waste water. The rest is from industrial sources, mainly meat production (76%) and paper manufacturing (17%): EPA. “Inventory of U.S. Greenhouse Gas Emissions and Sinks,” Table 7-18.

50. Of the organic material that goes into US landfills, 35% is food, 25% is textiles, 25% is paper, and 15% is yard waste: EPA. “Inventory of U.S. Greenhouse Gas Emissions and Sinks.” Assuming these materials produce methane at similar rates when they decompose, they produce 500 kg CO₂e, 300 kg CO₂e, 300 kg CO₂e, and 200 kg CO₂e, respectively. Composting the yard waste and one-third of the food waste (the post-consumer food waste) therefore prevents 400 kg CO₂e of methane emissions.

51. These estimates were derived from data in: EPA. “Inventory of U.S. Greenhouse Gas Emissions and Sinks.” See previous note.

52. In 2014, Amtrak used 2,200 Btu of energy per passenger mile: Stacy C. Davis et al. Transportation Energy Data Book, ed. 35. Oak Ridge National Laboratory, Pub #ORNL-6992, 2016, Table 9.10. One gallon of diesel has 137,000 Btu: US EIA. “Energy Explained.” [online]. eia.gov/energyexplained/index.cfm/index.cfm?page=about_energy_units. The combustion of this fuel creates 12.1 kg CO₂, which means in 2014 Amtrak emitted 0.19 kg CO₂ per passenger mile. Assuming that ⅔ of the passengers are in coach and that they take ½ the space of sleeper car passengers (approximately true for the Coast Starlight train) and are therefore responsible for ½ the emissions means Amtrak train travel emits 0.14 kg CO₂ per coach passenger mile and 0.28 kg CO₂ per sleeper passenger mile.

53. 184 passenger miles per gallon of diesel: Amy Zipkin, “Smoothing the rides on greyhound,” New York Times, May 17, 2008. [online]. nytimes.com/2008/05/17/business/17interview-long.html.

54. Davis et al. Transportation Energy Data Book, Table 9.10.

55. David J.C. MacKay. Sustainable Energy: Without the Hot Air. UIT, 2008, the chapter entitled “Planes II.”

56. EPA. “Inventory of U.S. Greenhouse Gas Emissions and Sinks.” They use a methane GWP of 25; for consistency with this book, I’ve scaled their methane estimate to a GWP of 65 by multiplying it by a factor of 2.6.

57. Calculation values and factors are based on US data. If you rent, you might need to coordinate with your landlord to estimate electricity and natural gas usage.

58. Anders Nordelöf et al. “Environmental impacts of hybrid, plug-in hybrid, and battery electric vehicles: What can we learn from life cycle assessment?” International Journal of Life Cycle Assessment 19(11) (2014). [online]. doi:10.1007/s11367-014-0788-0. Note that gas cars are estimated to have five tonnes CO₂e of embodied emissions, but this estimate will vary greatly depending on the size of the vehicle.

59. Recall that the US per capita vehicle miles of travel in 2013 was 9,400 miles, and that the average passenger vehicle on the road in the US in 2013 gets 21.6 miles per gallon. Therefore, the average vehicle burns 700 gallons of gas after 1.6 years.

60. National Renewable Energy Laboratory. “PV FAQs: What is the energy payback for PV?” [online]. nrel.gov/docs/fy05osti/37322.pdf. With an expected lifetime of 30 years, though, this is still a good deal.

61. As I explained in Chapter 5, roughly one-half of global emissions growth comes from growth in consumption. The other one-half comes from population growth.

62. For 2009, for children aged 5–15 yrs: Nancy McGuckin. “Travel to School in California: Findings from the California—National Household Travel Survey.” Prepared for Active Living Research, Bikes Belong Foundation, and the Safe Routes to School National Partnership, 2013, p. 13. [online]. travelbehavior.us/Nancy-pdfs/Travel to School in California.pdf.

63. One parent I know drives 20 miles each way—five tonnes of CO₂ and thousands of dollars in fuel costs for getting her kids to school! Having a uniformly strong public education system, with good schools in every neighborhood, isn’t just good for our kids and for the future of the US, it’s also good for the climate.

64. The US average fuel consumption of model-year 2008 vehicles sold (as opposed to on the road) was 20.8 miles per gallon; in 2016, it was 25.1 mpg.: University of Michigan Transportation Research Institute. [online]. umich.edu/~umtriswt/EDI_sales-weighted-mpg.html. I have used a value of 24.7 mpg in my calculations. Changes in average fuel consumption are driven by gasoline prices, although there is likely a lag time between gasoline price shifts and sales of larger vs. smaller vehicles.

65. Alliance for Water Efficiency. “Showering to Savings.” [online]. home-water-works.org/indoor-use/showers.

66. Estimated as follows:

(1) I took a baseline measurement with just the pilot lights running. (I turned the hot water heater to “vacation” mode so it wouldn’t switch on.) After 65 minutes, 1.7 ± 0.05 cubic feet had elapsed, a rate of 1.6 cubic feet per hour. (The uncertainty comes from my time measurement; I don’t know the uncertainty in the meter.) This amounts to 38 ± 1 cubic feet per day, about 0.4 therms.

(2) I turned off the heater pilot light. With the other two pilot lights running, the meter elapsed 0.85 ± 0.05 cubic feet in one hour (77 therms per year). So the heater pilot light had been accounting for ½ of the instantaneous total, but we run this pilot less than ½ the year. Averaging the two always-on pilots, I estimate that a typical pilot emits 460 kg CO₂e per year.

67. Suppose we want to heat 30 gallons of water from 60°F (16°C) to 120°F (49°C). It takes 8.33 BTU of thermal energy to raise 1 gallon of water 1°F, so our load requires 15,000 BTU. Burning 1 therm of natural gas yields 100,000 BTU, so our load requires burning 0.15 therms of natural gas, which releases 2 kg CO₂e.

68. Thanks to Parke Wilde for these arguments.

69. This tree planting option is likely a best-case scenario. For example, a company called Terrapass has several projects it suggests it will spend your money on. One Terrapass project (which I picked at random from their website) aims to provide a small amount of habitat for migratory birds in California. While this sounds like a nice project in its own right, it doesn’t remove CO₂ from the air. A secondary aim of this project is to provide “an important new revenue stream for rice growers.” Well, setting aside the fact that we shouldn’t be growing water-intensive rice in drought-stricken California in the first place, or the fact that conventional rice agriculture is a significant source of methane, could providing revenue to industrial agriculture corporations (with their large carbon footprints) really offset the flights of Terrapass’s customers?

70. Hunt and McFarlane. “‘Peak soil.’”

71. The Earth’s biomass contains 450–650 GtC, mostly in trees. But by 2015, humans had emitted 560 GtC from burning fossil fuels. To deal with this by planting trees, we’d have to add an additional global forest approximately equal to all the trees alive today, in addition to the reforestation to the 1750 state. Where would we put all those extra trees?

72. Elisabeth Rosenthal. “Paying more for flights eases guilt, not emissions.” New York Times, November 17, 2009. [online]. nytimes.com/2009/11/18/science/earth/18offset.html.

73. “Easily” here does not mean “trivially.” During the four-year period in which I was developing my methods, it was like having a moderately intense hobby. After this initial period, it became easy to maintain.

Chapter 10: Slow Travel

1. In addition, I carried a sleeping bag and pad, an extra shirt, an extra pair of shorts, a stash of surplus powdered Gatorade and Power Bars from the summer job, and not much else. I started off with a rain fly for shelter, but after a few days of biking against headwinds, I realized it wasn’t worth its weight, and I mailed it to Chicago.

2. The following book was helpful: Forest Gregg. SVO: Powering Your Vehicle with Straight Vegetable Oil. New Society, 2008.

3. Some “greasers” deal with the viscosity issue by blending other fuels, such as gasoline, into the veggie oil.

4. Maeby, she’ll get there. Maybe she won’t.

5. The viscosity of WVO can also be lowered through chemical means; biodiesel is essentially WVO that has been chemically modified for lower viscosity: Lyle Estill and Bob Armantrout. Backyard Biodiesel: How to Brew Your Own Fuel. New Society, 2015.

6. Global production of vegetable oil: Jim Lane, “Global 2016/17 vegetable oil production to hit record level: USDA,” Biofuels Digest, September 25, 2016. [online]. biofuelsdigest.com/bdigest/2016/09/25/global-201617-vegetable-oil-production-to-hit-record-level-usda/.

Yields per acre: Keith Addison. “Oil Yields and Characteristics.” Journey to Forever. [online]. journeytoforever.org/biodiesel_yield.html.

7. My yard has about 1/20th of an acre of growing space, and I’d grow the sunflowers organically, which likely reduces yield by 40%: M. Mazzoncini. “Sunflower under conventional and organic farming systems: Results from a long term experiment in Central Italy.” Aspects of Applied Biology 79, (2006). [online]. orgprints.org/10203/.

8. Maeby typically gets about 25 miles per gallon, but with the cubies on the roof, this dropped to about 22 miles per gallon.

9. Imagine all the gasoline you’ve burned in your life, together in one place. Multiply by the number of cars.

10. A few years earlier, one bright blue Tuesday morning, I did see some of the buildings fall. I’d stepped out of the Wall Street subway and onto that strip of island to a snowfall of singed papers falling gently from a burning World Trade Center. Sailing up to the island after the cruise, I tried to pick out the building I’d been sitting in as I talked on the phone with my dad, telling him I was OK, then repeating “please don’t let the second building fall, please don’t let the second building fall” as the second building fell, a lifetime ago.

11. The ship typically burns about 1.5 barrels per nautical mile. At the time of my trip, fuel was over $100 a barrel; fueling that round-trip cost about $1,000,000.

12. According to Climate Care, a carbon offsetting company: “Is cruising any greener than flying?” Guardian, December 20, 2006. [online]. theguardian.com/travel/2006/dec/20/cruises.green. This number for fossil-fueled cruising, 0.4 kg CO₂ per passenger mile, is reasonable: it’s what Spirit would emit if she carried 2,000 passengers (see next note).

13. The Spirit burns 1.5 barrels (63 gallons) of bunker fuel per nautical mile. Bunker fuel (residual fuel) emits 11.8 kg CO₂/gallon: US EIA. “Carbon Dioxide Emissions Coefficients.” Release date, February 2, 2016. [online]. eia.gov/environment/emissions/co2_vol_mass.cfm. Adding 20% extra for upstream emissions (see Chapter 9), this comes to 14.1 kg CO₂ / gallon. So over one nautical mile, Spirit emits 892 kg CO₂, or 780 kg CO₂ per statute mile. She has a 29,500 short ton cargo capacity, so with my 50 pounds of baggage, I accounted for 0.0000041 of the cargo, making my emissions 0.0032 kg CO₂ per mile.

Chapter 11: Meditation, a Foundation of Change

1. In the vipassana tradition, there’s no charge for courses, which run on a “pay it forward” basis through donations from people who have taken at least one course. The teachers and the people who run the course and cook the food are volunteers. This commitment to non-commercialism and selflessly helping others maintains the purity of the teaching. For more information: dhamma.org.

2. S. N. Goenka. “The Art of Living: Vipassana Meditation.” [online]. dhamma.org/en-US/about/art.

3. Robert A. F. Thurman. Essential Tibetan Buddhism, rev. ed. Harper-One, 1996.

4. Taking intoxicants may seem relatively harmless. However, being intoxicated makes it easier to break the other four precepts. For example, drinking makes it much easier to act violently. Also, I have friends who’ve received drunk driving convictions, which caused them great suffering.

5. For me, the transition away from breaking these precepts was gradual. For example, early in my meditation practice, I drank alcohol every day. As I practiced, I became aware that alcohol gave me a feeling of mental cloudiness and sapped my energy. I preferred feeling sober, so I gradually started drinking less. I’ve become sensitive to the distinct taste and smell of alcohol, and I don’t like it. If you love beer and wine, as I did, you don’t have to be afraid to give them up. But when you do drink, you will probably have a heightened awareness of the associated sensations, and you might choose to drink less.

6. There are studies based on other meditative techniques which also demonstrate benefits. There are few head-to-head studies comparing different meditation techniques.

7. Britta K. Hölzel et al. “Mindfulness practice leads to increases in regional brain gray matter density.” Psychiatry Research: Neuro imaging 191 (2011). [online]. doi:10.1016/j.pscychresns.2010.08.006; Sarah W. Lazar et al. “Meditation experience is associated with increased cortical thickness.” Neuroreport 16 (2005). [online]. ncbi.nlm.nih.gov/pmc/articles/PMC1361002/.

8. Hölzel et al. “Mindfulness practice leads to increases in regional brain gray matter density.”

9. Yvette I. Sheline et al. “Depression Duration But Not Age Predicts Hippocampal Volume Loss in Medically Healthy Women with Recurrent Major Depression.” The Journal of Neuroscience 19 (1999). [online]. jneurosci.org/content/19/12/5034.full.

10. For example: Zindel V. Segal et al. Mindfulness-Based Cognitive Therapy for Depression, 2nd ed. Guilford Press, 2012.

11. While in my early twenties, I had a bout of severe depression. I cannot begin to express the awfulness of that experience; I’m grateful to have made it out alive. Twice since I began meditating in 2003, during periods of stress during which I wasn’t keeping my regular meditation, I felt a sort of mental pain or pressure that reminded me of being depressed. It felt as though depression were trying to find its way back in. Both times, simply reinstating my meditation routine caused that feeling to vanish after a day or two. What’s more, my meditation experience is what allowed me to quickly recognize the incipient mental sensation in the first place.

12. Hölzel et al. “Mindfulness practice leads to increases in regional brain gray matter density.”

13. Philippe R. Goldin and James J. Gross. “Effects of Mindfulness-Based Stress Reduction (MBSR) on Emotion Regulation in Social Anxiety Disorder.” Emotion 10(1) (2010). [online]. doi:10.1037/a0018441.

14. T. L. Jacobs et al. “Self-reported mindfulness and cortisol during a Shamatha meditation retreat.” Health Psychology 32 (10) (2013). [online]. doi:10.1037/a0031362.

15. Lazar et al. “Meditation experience is associated with increased cortical thickness.”

16. Ibid.

17. T. Gard et al. “The potential effects of meditation on age-related cognitive decline: A systematic review.” Annals of the New York Academy of Sciences 1307 (2014). [online]. doi:10.1111/nyas.12348.

18. Judson A. Brewer et al. “Meditation experience is associated with differences in default mode network activity and connectivity.” Proceedings of the National Academy of Sciences 108 (2011). [online]. doi:10.1073/pnas.1112029108.

19. Matthew A. Killingsworth and Daniel T. Gilbert. “A wandering mind is an unhappy mind.” Science 330 (2010). [online]. doi:10.1126/science.1192439.

20. Brewer et al. “Meditation experience is associated with differences in default mode network activity and connectivity.”

21. N. E. Morone et al. “Mindfulness meditation for the treatment of chronic low back pain in older adults: A randomized controlled pilot study.” Pain 134(3) (2008). [online]. doi:10.1016/j.pain.2007.04.038.

22. David S. Black et al. “Mindfulness Meditation and Improvement in Sleep Quality and Daytime Impairment Among Older Adults With Sleep Disturbances: A Randomized Clinical Trial.” Journal of the American Medical Association Internal Medicine 175 (2015). [online]. doi:10.1001/jamainternmed.2014.8081. Also, vipassana cured my mom’s persistent insomnia.

23. Richard J. Davidson et al. “Alterations in Brain and Immune Function Produced by Mindfulness Meditation.” Psychosomatic Medicine 65(4) (2003). [online]. doi:10.1097/01.PSY.0000077505.67574.E3.

24. Joel W. Hughes et al. “Randomized Controlled Trial of Mindfulness-Based Stress Reduction for Prehypertension.” Psychosomatic Medicine 75(8) (2013). [online]. doi:10.1097/PSY.0b013e3182a3e4e5.

Chapter 12: Reconnecting with Mother Earth

1. Carolyn Dimitri et al. The 20th Century Transformation of U.S. Agriculture and Farm Policy. USDA Economic Information Bulletin Number 3, June 2005. [online]. ilovefarmers.org/downloads/The20thCenturyTransformationofU.S.AgricultureandFarmPolicy.pdf.

2. It’s one thing to grow fruits and veggies in a tiny yard, but grains had me perplexed. I failed at growing Sonora wheat, an heirloom well-suited to Southern California’s hot and dry conditions. Meantime, a sorghum volunteer, whose seed must have been pooped out by a bird, began to grow. I had no idea what it was, but it grew up on its own. I have a policy of not pulling out plants until I know what they are, and it paid off this time: eventually it dawned on me that I’d found an ideal grain crop. Or rather, it had found me.

3. A good guide: Eric Toensmeier. Perennial Vegetables from Artichokes to Zuiki Taro: A Gardener’s Guide to Over 100 Delicious, Easy-to-Grow Edibles. Chelsea Green, 2007.

4. Masanobu Fukuoka. The One-Straw Revolution: An Introduction to Natural Farming. Rodale Press, 1978.

5. Ibid., p. 52.

6. Ibid., p. 109.

7. Roc Martin. “The Amish Farmers Reinventing Organic Agriculture.” Atlantic, October 6. 2014. [online]. theatlantic.com/health/archive/2014/10/the-amish-farmer-replacing-pesticides-with-nutrition/380825//.

8. Humanure composting might break a municipal code where you live. Proceed at your own risk.

9. In one week, I use 3 or 4 gallons of water rinsing buckets. Back in my flush toilet days, I’d use over 100 gallons in a week (30 or so flushes at around 4 gallons per flush). What’s more, those rinse water gallons aren’t wasted: they support microbes working day and night to build soil.

10. Joseph C. Jenkins, The Humanure Handbook: A Guide to Composting Human Manure, 3rd ed. Jenkins Publishing, 2005. Jenkins, in turn, is indebted to an obscure World Bank treatise which lays out the basics of human manure composting with key data on hygiene: Richard G. Feachem et al. Transportation, Water and Telecommunications Department. Appropriate technology for water supply and sanitation: Health aspects of excreta and sullage management: A state-of-the-art review. World Bank, 1981. [online]. documents.worldbank.org/curated/en/929641467989573003/Appropriate-technology-for-water-supply-and-sanitation-health-aspects-of-excreta-and-sullage-management-a-state-of-the-art-review.

11. Many restaurants throw out five-gallon buckets; you can easily get as many as you want without using money. The box can be made from scrap or salvaged wood.

12. World Health Organization. “Cholera Fact Sheet” Updated October 2016. [online]. who.int/mediacentre/factsheets/fs107/en/.

13. Feachem, “Appropriate Technology,” p. 105.

14. During this experiment, nightly lows in Altadena were around 50°F and daily highs were around 70°F.

15. Humanure composting temperatures should be high enough to kill most weed seeds. In a study of six weed seeds, even the hardiest experienced 100% mortality after only three hours at 140°F (60°C): Ruth M. Dahlquist et al. “Time and Temperature Requirements for Weed Seed Thermal Death.” Weed Science 55(6) (2007). [online]. doi:10.1614/WS-04-178.1.

16. After two weeks, it was 130°F. After a month, it was around 110°F. I poured some water near the thermometer, and it went back to 130°F.

17. World Health Organization. “Sanitation Fact Sheet” Reviewed November 2016. [online]. who.int/mediacentre/factsheets/fs392/en/.

18. Jay P. Graham and Matthew L. Polizzotto. “Pit latrines and their impacts on groundwater quality: A systematic review.” Environmental Health Perspectives 121(5) (2013). [online]. doi:10.1289/ehp.1206028. This risk, although serious, remains poorly quantified.

19. World Health Organization. “Sanitation Fact Sheet.”

20. Nayantara Narayanan. “Horrifying fact: Almost all India’s water is contaminated by sewage.” Scroll.in, July 1, 2015. [online]. scroll.in/ article/737981/horrifying-fact-almost-all-indias-water-is-contami nated-by-sewage/.

21. US EPA. “Septic Systems Overview.” [online]. epa.gov/septic/septic-systems-overview.

22. Marylynn V. Yates. “Septic Tank Density and Ground-Water Contamination.” Groundwater 23(5) (1985). doi:10.1111/j.1745-6584.1985.tb01506.x.

23. Chenxi Wu et al. “Uptake of Pharmaceutical and Personal Care Products by Soybean Plants from Soils Applied with Biosolids and Irrigated with Contaminated Water.” Environmental Science & Technology 44 (2010). [online]. doi:10.1021/es1011115. Pharmaceuticals in this context are still poorly understood, part of a broad class of “emerging contaminants to the environment.” (Quote from USGS. “Land Application of Municipal Biosolids.” [online]. toxics.usgs.gov/regional/emc/municipal_biosolids.html.)

24. Not all cultures have shared our taboo about poop. F. H. King (in Farmers of Forty Centuries: Organic Farming in China, Korea, and Japan. 1911, repr., Dover, 2004) recounted that in ancient China night soil collectors would actually pay for the privilege of emptying privies, I assume from folks without gardens. Until recently, Mandarin Chinese usage did not include profane words for poop, as Western languages do. This uncomposted night soil wasn’t hygienic, but it did allow the ancient Chinese to develop a sustainable agriculture—something industrial civilization has so far failed to do.

25. My chickens love the larvae of the figeater beatle. My late favorite hen, Black Star, could jump and grab flying adults out of the air when they flew too low.

26. See David Quammen. Spillover: Animal Infections and the Next Human Pandemic. Norton, 2012.

27. Maryn McKenna. “The looming threat of avian flu.” New York Times Magazine, April 13, 2016. [online]. nytimes.com/2016/04/17/magazine/the-looming-threat-of-avian-flu.html.

28. Mary J. Gilchrist et al. “The potential role of concentrated animal feeding operations in infectious disease epidemics and antibiotic resistance.” Environmental Health Perspectives 115(2) (2007). [online]. doi:10.1289/ehp.8837.

29. An 18-inch box with a wire screen taped over a hole for ventilation.

30. Thomas D. Seeley. Honeybee Democracy. Princeton, 2010.

31. About half of my swarm captures stay; the other half will fly off after a day or two, probably to find a home more to their liking. I’ll arrive to find an empty box. I’ve recently started to use a piece of queen excluder over the entrance to keep the queen inside for the first few days, but I haven’t done this enough to say for sure if it helps.

32. Michael Bush. “Genetic Diversity in Bees.” The Practical Beekeeper website, 2008. [online]. bushfarms.com/beesgeneticdiversity.htm.

33. See Chapter 5.

34. Dennis vanEngelsdorp et al. “Colony Collapse Disorder: A Descriptive Study.” PLoS ONE 4(8) (2009). [online]. doi:10.1371/journal.pone.0006481.

35. I used to keep two hives on my roof as well. If you decide to go the roof route, make sure the hives have shade, and realize that a mature hive full of honey could weigh 200 pounds and present an interesting challenge to move.

Chapter 13: Opting Out of a Broken System

1. Around the same time, I added extra insulation to our attic floor, which reduces transmission heat from the hot attic to the living space, and makes sense in any climate. Other energy-saving cooling alternatives (that may work best in hot, dry climates) include a whole-house fan, radiant barrier under attic rafters, and a reflective “cool roof,” which has the additional benefit of reducing the urban heat island effect. If I ever replace my roof, it will be with a cool roof: heat waves are a bigger challenge in Southern California than cold snaps.

2. Access to machine shops is a perk of being part of a university community.

3. For example, see Mrs. Homegrown (a.k.a. Kelly Coyne). “A Homemade Mattress.” Root Simple blog, March 15, 2013. [online]. rootsimple.com/2013/03/a-homemade-mattress/.

4. See Jon Jandai. “Life is easy. Why do we make it so hard?” TEDxDoi Suthep, August 3, 2011. [online]. youtube.com/watch?v=21j_OCNLuYg.

5. Edited for clarity from Richard Whittaker. “A Conversation with Adam Campbell: A Taste For Life.” conversations.org website, November 30, 2012. [online]. conversations.org/story.php?sid=336.

6. See for example: Keiren. “Rocket Mass Heaters.” Blog entry. [online]. niftyhomestead.com/blog/rocket-mass-heaters/.

7. Jon Jandai. “Life is easy.” Also, Ianto Evans and Linda Smiley built a cob home for $500: Michael Smith and Ianto Evans. “Questions and Answers about Cob.” Natural Building Colloquium Southwest. [online]. networkearth.org/naturalbuilding/cob.html.

8. Stores overstock before holidays and then throw out two days’ worth of expiring food instead of one.

9. Organic doesn’t necessarily mean that pesticides weren’t used. Still, I’d rather eat an organic apple than a conventional one. See: Beth Hoffman. “Five reasons to eat organic apples: Pesticides, healthy communities, and you.” Forbes, April 23, 2012. [online]. forbes.com/sites/bethhoffman/2012/04/23/five-reasons-to-eat-organic-apples-pesticides-healthy-communities-and-you/#5b19cc846d21. As far as food certifications go, organic is the best we have; we should work together to continue strengthening it.

10. This takes an hour of my time every other week. I got this gig after I offered bread to my crop-swap group after a Christmas dumpster dive. Someone in the group was already working with the supermarket and asked me to help. This is how the universe works: when you are open to people, people are open to you.

11. Dana Gunders. “Wasted: How America Is Losing up to 40 Percent of Its Food from Farm to Fork to Landfill.” Natural Resources Defense Council Issue Paper #IP-12-06-B, August 2012. [online]. nrdc.org/sites/default/files/wasted-food-IP.pdf.

12. As far as preserving food goes, I also like canning homegrown tomatoes, drying fruit such as figs (laying trays of fruit on a car dashboard keeps the flies off), and saving up vegetable scraps in freezer bags to make broth.

13. There’s some evidence that safrole is carcinogenic in rats, at ingestion levels far greater than what you’d get from homemade root beer: Peter G. Wislocki et al. “Carcinogenic and Mutagenic Activities of Safrole, 1'-Hydroxysafrole, and Some Known or Possible Metabolites.” Cancer Research 37(6) (1977). [online]. cancerres.aacrjournals.org/content/37/6/1883.short. Many people use sassafras anyway.

14. I then obtained a card through the Permaculture Credit Union, the only card I could find with no connection to a large bank. That credit union is now managed by the Sandia Area Credit Union.

15. Sharon was inspired by the 40-day period of fasting observed during Christian Lent.

16. Luke Hurst. “HSBC warns clients of fossil fuel investment risks.” Newsweek, April 21, 2015. [online]. newsweek.com/hsbc-warns-clients-fossil-fuel-investment-risks-323886.

17. War Resisters League. “U.S. Federal Budget—2015 Fiscal Year: Where Your Income Tax Money Really Goes.” [online]. warresisters.org/sites/default/files/2015piechart—highres.pdf.

18. The W2 system makes war tax resistance more difficult. Take too many exemptions, and you risk being charged with W2 fraud.

19. New York Yearly Meeting. “Purchase Quarterly Meeting of the Religious Society of Friends (Quakers): Peace Tax Escrow Account.” [online]. nyym.org/purchasequarter/peacetax.html/.

20. Mark Koba. “U.S. military spending dwarfs rest of world.” NBC News, February 24, 2014. [online]. nbcnews.com/storyline/military-spending-cuts/u-s-military-spending-dwarfs-rest-world-n37461.

21. Meredith Bennett-Smith. “Womp! This Country Was Named the Greatest Threat To World Peace.” Huffington Post, January 2, 2014. [online]. huffingtonpost.com/2014/01/02/greatest-threat-world-peace-country_n_4531824.html.

22. Daniel Suelo interview by Shirley Jahad. Crawford Family Forum, Pasadena, California, March 26, 2012. Archived by Southern California Public Radio. [online]. scpr.org/events/2012/03/26/584/one-man-quit-money/.

23. The total time spent staring at screens in the US is closer to eight hours: Molly Brown. “Nielsen reports that the average American adult spends 11 hours per day on gadgets.” GeekWire, March 13, 2015. [online]. geekwire.com/2015/nielsen-reports-that-the-average-american-adult-spends-11-hours-per-day-on-gadgets/. The twelve years statistic assumes eight hours of sleep per day.

24. “Advertising to Children and Teens: Current Practices: A Common Sense Media Research Brief.” Common Sense Media, January 28, 2014. [online]. commonsensemedia.org/research/advertising-to-children-and-teens-current-practices.

25. Bruce E. Levine, “Does TV actually brainwash Americans?” Salon, October 30, 2012. [online]. salon.com/2012/10/30/does_tv_actually_brainwash_americans/.

26. Mengwei Bian and Louis Leung. “Linking Loneliness, Shyness, Smartphone Addiction Symptoms, and Patterns of Smartphone Use to Social Capital.” Social Science Computer Review 33(1) (2015). [online]. doi:10.1177/0894439314528779.

27. Kimberly S. Young and Robert C. Rogers. “The Relationship Between Depression and Internet Addiction.” CyberPsychology and Behavior. 1(1) (1998). [online]. doi:10.1089/cpb.1998.1.25.

28. If you do see such an action, please let me know what it is.

Chapter 14: Collective Action

1. Tom Mintier and Reuters. “Global warming pact approved, developing nations face few restrictions.” CNN, December 11, 1997. [online]. cnn.com/EARTH/9712/11/climate.conf/index.html.

2. Carbon Dioxide Information Analysis Center. “Global Fossil-Fuel CO₂ Emissions.” [online]. cdiac.ornl.gov/trends/emis/tre_glob_2013.html.

3. Joeri Rogelj et al. “Paris Agreement climate proposals need a boost to keep warming well below 2°C.” Nature 534 (2016). [online]. doi:10.1038/nature18307.

4. See IGM Economic Expert Panel. “Carbon Tax.” IGM Chicago, December 20, 2011. [online]. igmchicago.org/surveys/carbon-tax; Luca Taschini et al. “Carbon tax v cap-and-trade: Which is better?” Guardian, January 31, 2013. [online]. theguardian.com/environment/2013/jan/31/carbon-tax-cap-and-trade.

5. Calculated this way: $30 per tonne CO₂ times 0.0088 tonnes CO₂ per gallon, with an extra 28% for upstream emissions (see Chapter 9).

6. Calculated this way: $30 per tonne CO₂ times 20 tonnes CO₂e per person in the US.

7. Depending on the specifics of the policy, of course, children might not necessarily receive a full share. For example, at least one proposal calls for a half share for the first two children; in this case, a household with two adults and two children would receive $9,000 from a carbon price of $150 per tonne CO₂e.

8. Carbon Tax Center. “Ensuring Equity.” [online]. carbontax.org/?s=ensuring+equity.

9. Carbon Tax Center. “Dividends.” [online]. carbontax.org/?s=dividends.

10. A catalog with these carbon estimates would need to be assembled. In addition to making the border adjustment possible, by creating this catalog, we would learn a great deal about how carbon is embodied in our economy. The border adjustment would initially target carbon-intensive goods: iron, steel, cement, glass, paper, etc. It’s easy to calculate the adjustment in these cases, and together they capture the majority of embodied emissions. Estimates for goods with lower carbon intensities can be continually refined. This border adjustment would be consistent with WTO rules (i.e., “most favored nation” and “national treatment”). Also, the border adjustment money would stay separate from the fee and dividend money. The tariffs collected from imported goods would be used to pay refunds to domestic producers exporting to “dirty regimes.” In the case of the US, given the US trade deficit, this pot of money would likely grow over time; it would be up to Congress to decide how to spend the windfall. Exports of domestically produced fossil fuels themselves could be exempt from the border adjustment refund, putting upward pressure on the price of fossil fuels and further discouraging their use, even internationally.

11. R. A. “Do economists all favour a carbon tax?” Economist, September 19, 2011. [online]. economist.com/blogs/freeexchange/2011/09/climate-policy.

12. Goldman Sachs has lobbied hard for cap-and-trade. That should tell you something: Matt Taibbi. “The Great American Bubble Machine.” Rolling Stone, April 5, 2010. [online]. rollingstone.com/politics/news/the-great-american-bubble-machine-20100405.

13. Although emissions in Europe went down, the EU ETS probably wasn’t a significant cause: Olivier Gloaguen and Emilie Alberola. “Assessing the factors behind CO₂ emissions changes over the phases 1 and 2 of the EU ETS: An econometric analysis.” CDC Climat Recherche Working Paper No, 2013–15, October 2013. [online]. cdcclimat.com/IMG/pdf/13-10_cdc_climat_r_wp_13-15_assessing_the_factors_behing_co2_emissions_changes.pdf.

14. E.g., Paul Krugman. “Unhelpful Hansen.” New York Times, December 7, 2009. [online]. krugman.blogs.nytimes.com/2009/12/07/unhelpful-hansen.

15. P. F. “British Columbia’s carbon tax: The evidence mounts.” Economist, July 31, 2014. [online]. economist.com/blogs/americasview/2014/07/british-columbias-carbon-tax.

16. Dr. Stewart Elgie and Jessica McClay. “Policy Commentary/Commentaire BC’s Carbon Tax Shift Is Working Well after Four Years (Attention Ottawa).” Canadian Public Policy 39(2) (2013). [online]. energyindependentvt.org/wp-content/uploads/2014/11/BC_Carbon-Tax-success-story.pdf.

17. Scott Nystrom and Patrick Luckow. “The Economic, Climate, Fiscal, Power, and Demographic Impact of a National Fee-and-Dividend Carbon Tax.” Regional Economic Models, Inc. (REMI) and Synapse Energy Economics, Inc. [online]. citizensclimatelobby.org/wp-content/uploads/2014/06/REMI-carbon-tax-report-62141.pdf. Note that this study was funded by Citizens’ Climate Lobby, an advocacy group, but that REMI has a reputation for being unbiased.

18. Ibid.; and Marc Breslow et al. “Analysis of a Carbon Fee or Tax as a Mechanism to Reduce GHG Emissions in Massachusetts.” prepared for the Massachussetts Department of Energy Resources, December, 2014. [online]. mass.gov/eea/docs/doer/fuels/mass-carbon-tax-study.pdf.

19. Statistics Canada, via P. F. “British Columbia’s carbon tax.” Note that the BC carbon fee is implemented as a sales tax, and returns 100% of revenues by lowering taxes.

20. Greg Mankiw. “How Not to Pass a Carbon Tax.” Blog post, August 3, 2015. [online]. gregmankiw.blogspot.ca/2015/08/how-not-to-pass-carbon-tax.html.

21. Jerry Taylor. “The Conservative Case for a Carbon Tax.” Niskanen Center, March 23, 2015. [online]. niskanencenter.org/wp-content/uploads/2015/03/The-Conservative-Case-for-a-Carbon-Tax1.pdf.

22. Ted Deutch and Carlos Curbelo. “Creating a bipartisan climate to discuss climate change in Congress.” The Hill, March 24, 2016. [online]. thehill.com/blogs/congress-blog/energy-environment/274061-creating-a-bipartisan-climate-to-discuss-climate.

23. Editorial Board. “Even Big Oil Wants a Carbon Tax.” Bloomberg View, June 1, 2015. [online]. bloomberg.com/view/articles/2015-06-01/even-big-oil-wants-a-carbon-tax.

24. Helge Lund et al. “Letter to Ms. Christiana Figueres and Mr. Laurent Fabius.” May 29, 2015. [online]. bp.com/content/dam/bp/pdf/press/paying-for-carbon.pdf.

25. Alan S. Blinder. “The Carbon Tax Miracle Cure.” Wall Street Journal, January 31, 2011. [online]. wsj.com/articles/SB10001424052748703893104576108610681576914.

26. Annually, 3.7 million deaths are caused by outdoor air pollution, which is mainly from burning fossil fuels: World Health Organization. “7 million premature deaths annually linked to air pollution.” March 25, 2014. [online]. who.int/mediacentre/news/releases/2014 /air-pollution/en/. Annually, indoor and outdoor pollution together cost $5 trillion, not even counting healthcare costs: John Vidal. “Air pollution costs trillions and holds back poor countries, says World Bank.” The Guardian, September 8, 2016. [online]. theguardian.com/global-development/2016/sep/08/air-pollution-costs-trillions-holds-back-poor-countries-world-bank.

27. Fabio Caiazzo et al. “Air pollution and early deaths in the United States. Part I: Quantifying the impact of major sectors in 2005.” Atmospheric Environment 79 (2013). [online]. doi:10.1016/j.atmosenv.2013.05.081.

28. It only takes a few minutes to write a letter, and it’s a lot of fun if it gets published. One of my letters, which pretty well sums up my perspective on climate action, can be found at: “Climate solutions: From marches to policies.” New York Times, September 22, 2014. [online]. nytimes.com/2014/09/23/opinion/climate-solutions-from-marches-to-policies.html.

29. US EIA. “Frequently asked questions: How much of U.S. carbon dioxide emissions are associated with electricity generation?” [online]. eia.gov/tools/faqs/faq.cfm?id=77&t=11.

30. A terawatt (TW) is one trillion watts of power; a TWh is the energy needed to provide a TW of power for an hour. 1 TWh = 1 billion kWh. The 4,070 TWh figure is from: US EIA. “Electric Power Annual 2013.” March 2015. [online]. eia.gov/electricity/annual/archive/03482013.pdf.

31. Ibid.: Nuclear: 790 TWh; hydroelectric: 270 TWh; non-hydroelectric renewables: 250 TWh. Wind produced 168 TWh, or 4.1% of the total, while solar power (thermal and photovoltaic) produced 9 TWh, or 0.2% of the total.

32. Three-quarters of US electricity is consumed by residential and commercial users (with each sector using about the same amount) and ¼ is consumed by industry (US EIA. “Annual Energy Outlook 2017.” [online]. eia.gov/outlooks/aeo/). In our household, we use less than 1/10 the electricity per person than the US average. While this argues for easy and deep reductions in the residential sector, I suspect the commercial sector could easily make similar reductions: the lights in many office buildings stay on all night, for example.

33. In 2013, the US used 6,900 kg oil equivalent per person per year, whereas the UK used 3,000: World Bank. “Energy use (kg of oil equivalent per capita).” [online]. data.worldbank.org/indicator/EG.USE.PCAP.KG.OE.

34. Calculated this way: (4,070 TWh/yr / 2) − (790 TWh/yr + 270 TWh/yr + 250 TWh/yr)

35. Oil Change International. “Fossil Fuel Subsidies: Overview.” [online]. priceofoil.org/fossil-fuel-subsidies/.

36. David Coady et al. “How Large Are Global Energy Subsidies?” International Monetary Fund working paper #WP/15/105. [online]. imf.org/external/pubs/ft/wp/2015/wp15105.pdf.

37. Our Children’s Trust. [online]. ourchildrenstrust.org/. The suit makes two claims. First, a constitutional claim that “the government’s aggregate actions, including subsidizing, permitting and facilitating the development, transportation, and combustion of fossil fuels, violates the youths’ substantive due process rights under the 5th Amendment’s protection against deprivation of life, liberty and property without due process of law.” The case isn’t challenging the government’s inaction; it challenges its direct action toward making global warming worse. Second, a public trust doctrine claim that “same actions...violate the federal government’s fiduciary obligation to preserve essential natural resources for the benefit of all present and future generations.”

38. Tony Dokoupil. “Big Oil joins legal fight against little kids over climate change.” MSNBC, August 14, 2015, updated November 13, 2015. [online]. msnbc.com/msnbc/big-oil-joins-legal-fight-little-kids-over-climate-change.

39. Two charts were part of an exhibit the plaintiffs’ attorneys presented to the court on September 13, 2016: Our Children’s Trust. “Details of Proceedings.” [online]. ourchildrenstrust.org/federal-proceedings/.

40. Sophia V. Schweitzer. “Are countries legally required to protect their citizens from climate change?” Ensia, July 15, 2015. [online]. ensia.com/features/are-countries-legally-required-to-protect-their-citizens-from-climate-change/.

41. Oxfam. “62 people own the same as half the world, reveals Oxfam Davos report.” Press release, January 18, 2016. [online]. oxfam.org/en/pressroom/pressreleases/2016-01-18/62-people-own-same-half-world-reveals-oxfam-davos-report.

42. A billionaire would respond that the source of his wealth was his brilliant idea. But doesn’t that idea just provide the means with which to extract (and therefore concentrate and accumulate) the distributed wealth of labor or resources? Ideas can serve to mobilize and rearrange labor and resources, but the idea by itself—without that labor and those resources—does not constitute wealth. Thomas Frank wrote: “Many of our most vaunted innovations are simply methods—electronic or otherwise—of pulling off some age-old profit-maximizing maneuver by new and unregulated means.” Thomas Frank. Listen, Liberal: Or, What Ever Happened to the Party of the People? Metropolitan Books, 2016, p. 209.

43. Paul Davidson. “Decline of unions has hurt all workers: Study.” USA Today, August 30, 2016. [online]. usatoday.com/story/money/2016/08/30/decline-unions-has-hurt-all-workers-study/89557266/. Unions have done a world of good since their formation in mid-19th-century America, bringing us such wonderful things as weekends, to name but one example. Still, unions sometimes push their negotiations too far, perhaps doing themselves more harm than good by fueling an opposition that paints them as unreasonably greedy and corrupt.

44. David Rotman. “How Technology Is Destroying Jobs.” MIT Technology Review, June 12, 2013. [online]. technologyreview.com/s/515926/how-technology-is-destroying-jobs/.

45. For most of US history, lobbying was strongly censured by the courts, and has at times been illegal in some states: Alex Mayyasi. “When Lobbying Was Illegal.” Priceonomics, April 15, 2016. [online]. priceonomics.com/when-lobbying-was-illegal/.

46. For an excellent discussion of the problems arising from international trade as we’ve structured it, see Annie Leonard. The Story of Stuff.

47. Meadows. “Leverage Points: Places to Intervene in a System.”

48. Gilda Sedgh et al. “Intended and Unintended Pregnancies Worldwide in 2012 and Recent Trends.” Studies in Family Planning 45(3) (2014). [online]. doi:10.1111/j.1728-4465.2014.00393.x.

49. There are deep connections between Christianity, Islam, and population growth. Muslims and Christians have the highest fertility rates of any religion, at 3.1 and 2.7 children per woman, respectively (compared to the global average of 2.5 and the replacement rate of 2.1). The world’s third-largest religion, Hinduism, has a fertility rate of 2.4: Pew Research Center. “The Future of World Religions: Population Growth Projections, 2010—2050.” April 2, 2015. [online]. pewforum.org/2015/04/02/religious-projections-2010-2050/.

50. Wilson. Half-Earth.

51. Robert H. MacArthur and Edward O. Wilson. Theory of Island Biogeography. Monographs in Population Biology 1, Princeton, 1967.

52. Thanks to Noam Chomsky for articulating this point: Noam Chomsky. “Noam Chomsky on Trump and the decline of the American Superpower.” YouTube, December 5, 2016. [online]. youtube.com/watch?v=Yp74MQBGMnk.

Chapter 15: Community

1. Henry David Thoreau. Walden. Internet Bookmobile, 2004, Chapter 1, “Economy,” pp. 25 and 26. [online]. eldritchpress.org/walden5.pdf.

2. Meadows. “Leverage Points: Places to Intervene in a System.”

3. The concept of “online community” seemed promising at first, and in 2009 or thereabouts, I started a “350 Los Angeles” Facebook group. 350.org is an organization of climate activists that takes its name from the CO₂ atmospheric concentration deemed to be the maximum safe level by climate scientist James Hansen (350 parts per million). While Facebook activism might work well for some people, my own experience of “350 Los Angeles” on Facebook turned out to be pointless and disempowering: I’d post diatribes that disappeared into the internet void and organize events to which no one showed up.

4. A PVC pipe receives my washing machine drain hose; the hose empties into a long narrow trench between my avocado and orange trees that’s filled with wood chip mulch (used only with sodium-free detergents).

5. These circles were pioneered by my friend Nipun Mehta and have grown into an organic network of gift economy: Awakin. [online]. awakin.org.

6. For links to groups, see: Transition Network. [online]. transitionnetwork.org.

7. For details about projects in California, see: Clean Power Exchange. [online]. cleanpowerexchange.org/.

8. Sonoma Clean Power [online]. sonomacleanpower.org/; Marin Clean Energy [online]. mcecleanenergy.org/.

9. See the incredible short film: Ben C. Solomon and Tommy Trenchard. “Erison and the ebola soccer survivors,” New York Times, 2015. [online]. nytimes.com/video/world/africa/100000003815213/erison-and-the-ebola-soccer-survivors.html.

10. Lara P. Clark et al. “National Patterns in Environmental Injustice and Inequality: Outdoor NO2 Air Pollution in the United States.” PLoS ONE 9(4) (2014). doi:10.1371/journal.pone.0094431.

11. For example: Heather Clancy. “TNC’s Mark Tercek: Protect, transform and inspire.” GreenBiz, July 9, 2015. [online]. greenbiz.com/article/tncs-mark-tercek-protect-transform-and-inspire.

12. Tami Luhby. “The black-white economic divide in 5 charts.” CNN Money, November 25, 2015. [online]. money.cnn.com/2015/11/24/news/economy/blacks-whites-inequality/index.html.

13. I am grateful to Daniel Suelo for teaching me about grace.