7
Energy and Global Environmental Issues
Energy is a fundamental unifying concept for physical and biological scientists because it drives all Earth systems. Energy is neither created nor destroyed, it simply changes form. Therefore, energy can never be “used up.” When nuclear fusion in the dense gas cloud of the sun releases the energy of the atom, it transforms that energy to various forms of electromagnetic energy. The exact amount of energy that was held in the nuclear bonds of the hydrogen or helium atoms reacting in the sun is the amount released as light, heat, and other forms of energy.
FORMS AND SOURCES OF ENERGY
Forms of Energy
Energy exists in a variety of forms. We know and are familiar with electromagnetic energy as light, heat, radio waves, television signals, and microwaves. Importantly, energy can be converted from one form to another. Nuclear energy of atoms of the sun is converted to electromagnetic energy, which is captured by plants and stored as chemical energy. Chemical energy stored in food is used to power the mechanical movements of activity — to walk, open doors, hunt. Mechanical energy is used to move cars, open bottles, and crack nuts with a nutcracker. Mechanical energy is the force that dug the Grand Canyon and that powers turbines to create electricity at hydroelectric dams. Thermal energy is what we commonly experience as heat. Electrical energy is converted to thermal energy in toasters and ovens to prepare the chemical energy in food. The chemical energy derived from the food is converted to the mechanical energy of pushing down the toaster button. Energy is commonly converted from one form to another throughout our lives every day. Thinking about these transformations or conversions helps elucidate the energetic basis of life on Earth.
Potential and Kinetic Energy
One way to imagine energy never being created or destroyed, but rather changing form, is to hold a ball at shoulder height. The ball is full of potential energy, the energy of position. If the ball drops, it has the power (the energy) to bounce if it hits the floor. Even though the ball is not moving when held at shoulder height, we think of it as having energy by virtue of its position in space. When the ball is dropped, its potential energy is transformed to the energy of motion, kinetic energy. The ball’s speed increases all the way to the floor as its potential energy is completely transformed to kinetic energy. What happens when the ball hits the floor? Suddenly its kinetic energy (the energy of motion) is transformed again. Some of the kinetic energy of the falling ball is transformed to mechanical energy, sound; some of the kinetic energy of the falling ball is transformed to light (a sensitive enough device might even be able to detect it); and some of the kinetic energy of the falling ball is transformed to heat (thermal energy). Dribble a basketball in one place on the floor for a few minutes, then feel the floor. It will be slightly warmer than the floor a few feet away. Most of the kinetic energy of the falling ball will be transformed to elastic potential energy, represented by the deforming or compressing of one side of the ball. This elastic deformation is what stores the energy that will power the rise (the bounce) of the ball back toward your hand. But will a ball ever bounce all the way back to the point from which it was dropped? It can’t, because some of its original potential energy has been transformed to heat, sound, and light.
Sources of Energy
Energy on Earth is derived from two sources: geothermal heat generated within the core of the planet and electromagnetic energy coming from the sun, most notably heat and light.
Energy within the Earth
Earth’s interior is not a simple homogeneous mass of solid rock. There is quite a lot of variation among layers, in terms of composition, density, and phase (liquid vs solid). The Earth’s core is a tremendous source of heat — some theorize that the Earth’s core is hotter than the surface of the sun, around 5,500°C! This intense heat is derived primarily from two sources, primordial heat and radioactive decay.
Primordial Heat. The Earth was first formed 4.5 billion years ago by bits of rock and dust coalescing as they orbited the sun, and these bits of rock contained a certain amount of energy. As the rocks piled up deeper and deeper, some of that energy was trapped. Some of the kinetic energy of the rocks’ motion was also converted to thermal energy (heat), and thus huge amounts of energy were trapped deep in the core of the developing Earth as heat. This heat, coupled with heat generated by radioactive decay in the core, has been enough to keep the outer core in a liquid state, despite the great pressure the material is under. Heat conduction from the outer core drives the convective flow of the solid but ductile mantle, and ultimately plate tectonics, on the surface of the Earth.
Radioactive Decay. The heat produced by radioactive decay of, for example, potassium 40, uranium 238, uranium 235, and thorium 232, combined with the original heat from the Earth’s formation, drives the global geological cycle, including the motions of tectonic plates and the continents that ride as components of those plates, the eruption of volcanoes, the thundering of earthquakes, and the uplifting of mountains. The Earth is constantly releasing the heat stored and produced deep within its core. How quickly the core heat of the Earth is lost depends on a number of factors, including the production of heat through radioactive decay, which diminishes over time, distance to the surface, materials the heat must travel through to reach the surface, and the insulating properties of the mantle and atmosphere. The moon, Mars, and Venus are geologically dead because they have lost all of their internal heat. Thanks to the insulating properties of the crust, the Earth will probably retain its core heat until long after the sun swells to swallow it. If the Earth’s internal heat were all dissipated, like the moon’s has been, the motions of the continents would end. Volcanoes would no longer erupt and add to the land surface area, and the continents would eventually be washed away by erosion into the oceans and not be rebuilt.
Internal structure of the Earth. Not to scale; the crust should be far thinner but is drawn so that it will show. Used with permission from the National Energy Education Development Project, www.need.org
Energy from the Sun
In order to carry out any activity — waking up, walking, breathing, eating, flying, hunting, mating — energy is required. Virtually all of the energy driving the common biological world is derived from nuclear reactions taking place within the sun. The sun is composed of hydrogen and helium, which are involved in continuous nuclear reactions. Nuclear fusion means the joining of two atoms, while nuclear fission is the splitting of the atomic nucleus. Both fusion and fission liberate huge amounts of energy. The sun is a giant ball of gasses undergoing continuous fusion reactions. The nuclear reactions of the sun send vast amounts of energy out into space as electromagnetic waves, which are captured by photosynthetic organisms and drive all life on Earth.
THE ENERGETIC BASIS OF LIFE
When the sun’s energy arrives on the Earth, it is transformed in two key ways. Some of the solar energy is used to change water from solid to liquid or from liquid to gas. Water, perhaps the most amazing molecule on Earth, can exist in three states, or phases: solid ice, liquid water, and gaseous vapor. Transforming water from solid ice to liquid water (a phase change) or from liquid to gaseous water vapor (another phase change) requires large amounts of energy. On Earth, water is one of the primary acceptors of energy from the sun. Without the sun’s continuous energy input, all the water on Earth would gradually lose its energy to the dark void of space and freeze. The various transformations of water from one phase to another drive the planetary climate system. The energy transformations of water from ice (solid) to river (liquid) to water vapor (a gas which condenses into clouds) to rain (liquid) or snow (solid) are examples of some of the primary determinants of the physical conditions we take for granted, and upon which life depends.
Photosynthesis is the energetic basis of all life on Earth. Without green plants there would be no life as we know it. Used with permission from the National Energy Education Development Project, www.need.org
The second form of energy transformation on Earth is when the sun’s electromagnetic radiation is transformed to the energy of chemical bonds in living systems. This is a fact that is easy to overlook, but without plants’ ability to convert the sun’s energy, there would be virtually no life on Earth. Photosynthesis is the second energy transformation upon which almost all life depends. Green plants and algae use the sun’s energy to build chemicals capable of storing that energy. The primary chemical used to store the sun’s energy and to power life is glucose (C6H12O6). Glucose is the transportable form of energy in biological systems. It is used to drive the process of aerobic respiration, where glucose reacts with oxygen to release energy, carbon dioxide, and water. Respiration provides energy for all the cell’s activities. Glucose supplies the energy for growth, reproduction, and all other aspects of biological activity. In sum, the sun’s energy is captured in the cells of green plants, and those plants then provide the chemical energy to drive all other forms of life on Earth. There are interesting exceptions to life relying on photosynthesis, such as complex communities found in deep-sea hydrothermal vents where no sunlight reaches. Life at these vents begins with the thermal energy being released from deep within the planet. Organisms there convert energy into food in a process known as chemosynthesis.
Energy loss in a food chain: 90 percent of the usable energy in an organism is lost at each step. The 90 percent is converted to heat and other unrecoverable forms of energy. Adapted from the University of Maine Cooperative Extension’s Connections to Our Earth: Leader’s Guide, Orono, Maine, 1995
Energy transformations in biological systems are inefficient. Each time a rabbit eats some grass, only about 10 percent of the energy stored in the grass is converted to usable energy in the animal. When a rattlesnake eats the rabbit, about 10 percent of the energy is successfully captured by the snake. When a coyote or a red-tailed hawk then eats the snake, the energy “loss” is similarly about 90 percent. Each time energy is exchanged in a food web, the loss in conversion is about 90 percent. This is a terrific limiting factor on the number of trophic levels a food web can support. It is the reason food chains almost never go beyond four or five transformations. It is more energetically efficient when people eat grains, vegetables, and fruits as compared with eating meat. Because the food source has gone through fewer transformations, less energy has been converted to unusable forms. Each time energy is converted in a food web, the “lost” 90 percent is used to heat the air or in other ways that are not useful. No energy goes away. We call this “energy loss,” but it is really not a loss of energy but a degradation of a highly usable form of energy to a much less usable form.
ENERGY USE BY PEOPLE
People are masters of turning the chemical bonds of matter into energy. Energy warms our homes. It powers cars, the trucks that bring food, and the tractors that grow food. Electrical energy powers computers, radios, washing machines, and water heaters. Virtually everything about human life is intimately bound to energy use, though the dominant forms of energy have changed over the millennia.
The two most common forms of energy Americans are familiar with are electricity and gasoline. Electricity is the flow of electrons. To generate electricity requires setting electrons in motion. An electric generator is a device that changes mechanical energy to electrical energy. Most large-scale electric generation is done using a turbine powered by wind, water, coal, or natural gas. The power sources for turning the turbine differ, but once a turbine is set in motion, the mechanical energy of the rotating shaft can be used to generate electricity. Gasoline perhaps shouldn’t be referred to as a form of energy. Technically, gasoline is a potential source of energy. Only when the gas is burned and the controlled explosion is converted to mechanical energy (the movement of the piston) can the original source (the gas) be used to power useful work.
About 90 percent of the energy used by people globally is generated by burning fossil fuels. Fossil fuels are carbon-rich compounds formed from the fossilized bodies of ancient plants and animals. Ancient plants captured the sun’s energy and then were buried for huge spans of time. Fossil fuels are the most concentrated and therefore the most convenient form of energy on Earth. Unfortunately, fossil fuels are not renewable on a time scale of interest to humans. Essentially, there is only so much oil in the ground. Although it is not known exactly how much oil is in the ground, we know that the supply is limited. For this reason, fossil fuels are termed nonrenewable resources. Unlike the energy of the sun, which arrives on Earth at a constant rate essentially in perpetuity, fossil fuels are a one-time bonanza.
Fossil fuels come in three general forms: oil, coal, and natural gas. They have, for about a century, been the main energy source powering society. Fossil fuels are inexpensive to obtain and convenient to transport and store. The technology to transform fossil fuels to electricity is simple and well developed. Unfortunately, within 100 years the quantities of petroleum and natural gas available will be largely depleted. World coal supplies are projected to last about 400 years at present rates of consumption. Estimations of fossil fuels reserves are, however, not a simple calculation but a complex interplay of what is in the ground, future demand, production technology, and price (i.e., the incentive to go after increasingly difficult-to-obtain reserves).
Coal is a solid and is extracted from the earth using digging and mining techniques and heavy machinery. Coal is used for firing power plants to produce electricity, and for steel production. Oil is a liquid, procured by drilling and pumping, and is used to produce gasoline, diesel fuel, and plastic products. Natural gas (methane) is the gaseous form of high-energy fossil carbon and will be familiar to many as the cleanest- burning form of home heating energy. About half of the natural gas used in California is used to fire power plants to make electricity.
California currently has no coal-fired power plants. This is commendable in terms of maintaining air quality. Coal is a dirty source of energy, and coal-fired power plants are notorious contributors to both global carbon issues and regional air quality issues. California imports electricity from coal-fired power plants as far away as Utah and Wyoming, essentially exporting air pollution to neighboring states with less stringent air quality regulations. However, new EPA rules for coal-fired plants and California’s Assembly Bill 32 to reduce greenhouse gas levels have led California utilities to reduce the amount of energy imported from coal-fired plants. In California, power plants fired with natural gas (methane) provide about 40 percent of the electricity used in the state. This is advantageous in that natural gas is the cleanest-burning fossil fuel. The disadvantage of using natural gas for producing electricity is that it is an inefficient use of the natural gas, compared with using it directly to heat homes. Only about half of the energy stored in a given volume of natural gas is captured as electricity in a power plant, whereas burning it to heat a home can be 96 percent efficient.
The extraction and use of coal, oil, and natural gas create undesirable by-products. Coal extraction (coal mining) is highly dangerous work and employs methods, such as mountaintop removal, with extreme environmental consequences. Oil extraction and transportation can produce accidents that seriously contaminate sensitive ecosystems. Most notoriously, extraction and combustion of the carbon-rich molecules which store energy in fossil fuels produce CO2 (carbon dioxide), a greenhouse gas. Natural gas is methane (CH4), itself a potent greenhouse gas. Both CO2 and methane are primary contributors to climate change. Ethanol burns more cleanly than gasoline in terms of particulates but similarly produces CO2 emissions which may eventually be unacceptable in a warming world.
Another form of nonrenewable energy is nuclear power. The best estimates are that the current relatively modest rate of consumption of uranium 235 (U-235, the “fuel” used in nuclear reactors) could continue for between 100 and 200 years. If the rate of consumption of U-235 were dramatically increased by building many more nuclear power plants, the global supply of U-235 would be depleted more quickly. Nuclear power is clean in the sense that operating the power plants does not emit carbon dioxide and thus does not contribute to global warming. However, like fossil fuels, nuclear power is a nonrenewable form of energy and supplies of U-235 will eventually be exhausted.
More immediate drawbacks to nuclear power are the cost; the highly dangerous, long-lived radioactive waste produced in the process; and the possibility of a nuclear meltdown. The first generation of nuclear power plants was made economical through federal subsidies to the industry. As the subsidies have been withdrawn and power companies have had to face the entire cost of design, permitting, operation, and decommissioning of highly complex facilities, nuclear power has looked less economically attractive.
Nuclear waste may remain highly toxic for 600 years or more. Many engineers argue that the technical problems of storing dangerous nuclear waste are surmountable, but locating a storage area for the waste presents huge political and social problems. (Who wants a nuclear waste site nearby?)
Another problem associated with nuclear power plants is the highly technical process of running them safely. When the process is not carefully monitored and controlled, the outcome can lead to events such as the meltdown at Chernobyl in 1986. In addition, uncontrollable events such as the combination of a giant earthquake and a tsunami can overwhelm even plants that have backup systems, as was the case in Japan in 2011.
Geothermal energy is a clean, non-carbon-emitting power source that in some ways straddles the border between a renewable and a nonrenewable energy source. The mass of heat trapped in the interior of the Earth would essentially be inexhaustible if it were all available to be tapped. However, the portion accessible from the surface is small and often distant from major metropolitan areas where the power is needed. The technology used to transform the Earth’s heat to usable forms, generally electricity, seems to make geothermal energy more like nonrenewable than renewable resources. In New Zealand, for instance, most electricity was produced by geothermal generation for about 30 years, but these sources have been depleted and are no longer of economic utility. Iceland, on the other hand, runs almost completely on geothermal power provided by superficial hot water vents likely to be available far into the future.
Geothermal has minor problems associated with disposal of contaminated water, which could probably be overcome with the proper attention to technology. Another challenge for geothermal energy is that the potential resource is sometimes located in some of the most pristine park lands (such as Yellowstone), where people will object to industrial development.
Wood for fuel also straddles the border between renewable and nonrenewable. Wood is the primary cooking and heating fuel for much of the world. Trees are a renewable resource but not necessarily within the time frame needed for the people who depend on them. In many parts of the world, wood needs exceed supply, and wood gatherers have to travel farther and farther from home to find enough fuel. The collection of wood as an energy source is associated with the denuding of hillsides, leading to habitat destruction, soil erosion, and flooding. The burning of wood also produces CO2, a greenhouse gas.
The renewable forms of energy available to humans include solar, wind, hydroelectric, wave, and tidal. While fossil fuels are concentrated forms of energy, renewables are dilute sources of energy. The cost of collecting dilute sources of energy can be high, so as long as fossil fuels remain cheap, renewable sources can compete economically only with subsidies.
Solar power has huge potential, for both small-scale and industrial applications. Solar energy can be trapped in many forms, from small-scale home water heaters, to industrial-strength solar arrays in the desert that use curved mirrors to heat water which turns turbines to generate electricity. Houses and office buildings can be heated passively by orienting windows to capture solar energy. Another method of capturing the sun’s energy directly is with solar cells, which capture the sun’s electromagnetic energy and convert it directly to electricity.
Solar is a clean source of power that does not emit carbon during the operation phase. All sources of power emit carbon during the manufacturing phase (e.g., making solar panels), thus the common term carbon neutral is somewhat misleading and is not used here. Solar is a renewable source of power, and the prognosis for the sun to rise tomorrow is good. Solar power is currently expensive compared with fossil fuels, but that is partly due to subsidies that benefit oil companies. The cost structure of these competing sources of energy is changing as technology improves and growing demand facilitates mass production of solar equipment and technology. The comparative cost of solar energy may change as costs associated with global warming become more explicitly attached to the burning of fossil fuels.
Solar energy is currently one of the most promising new ways to generate power. However, utility-scale solar farms use a lot of land, and when that means covering extensive amounts of fragile desert ecosystems, this presents serious concerns for biodiversity conservation. The best approach to avoid these impacts is to locate renewable energy projects on degraded lands such as former mine sites or on existing rooftops.
Wind power captures the mechanical energy of wind via large arrays of windmills (wind-powered blades that drive a turbine, which is used to generate electricity). Wind power is a clean, non-carbon-emitting source of power. Its main limitation seems to be the lack of places where the wind is strong and reliable enough to make operation economical. Wind farm proposals often run into local opposition based on aesthetics (“not in my back yard”) and opposition from bird lovers and biologists who are concerned about bats and migratory birds, especially large raptors like golden eagles and red-tailed hawks, being killed by the spinning blades.
Hydroelectric energy captures the mechanical energy of falling water via dams and turbines to generate electricity. Hydroelectric power supplies about 10 percent of America’s electricity today. The percentage of hydropower in California is higher than the national average, 15 percent. Hydropower is clean in the sense that it emits no carbon and does not contribute to global warming. The unfortunate side of hydropower is that damming rivers dramatically alters the ecology of the river. The Pacific salmon crisis, with 11 species of salmonids on the federal endangered species list and others sure to join it, is largely a result of hydroelectric dams. The same is true of the Colorado River, where three of the original 8 native species of fish are extinct and two are endangered as a result of hydroelectric dams. Before the dams were built, the Colorado River system was a seasonal, muddy, warm-water system. The dams have transformed the river into a cold, clear, low-nutrient system. The Colorado before the dams supported 8 native species of fish and virtually no nonnative fish species. Currently the Colorado supports about 20 species of nonnative fish and reduced populations of the 5 remaining native species.
Ocean wave power and tidal power are largely ideas in the development stage. Both are essentially inexhaustible supplies of energy, if the technical challenges to tapping them can be overcome. Wave power is captured by buoys anchored to the seafloor offshore. Wave power has the classic problem of the difficulty of harnessing a very dilute energy source. The cost of harvesting it makes it uneconomical. Tidal power is generally captured in estuaries, using dams that allow the tide to raise the water level and then run the outflow through turbines to create electricity. Tidal power works well when you have a really good site (e.g., the Rance River on the French side of the English Channel), but not elsewhere. Tidal power dams like Rance have environmental problems similar to river dams.
Alternative forms of liquid fuel for powering vehicles (biofuels) are now being developed. Ethanol is an energy-rich liquid that can (theoretically) be produced from various plant products (sugarcane, corn, wood, agricultural waste, fruits). Biofuels are relatively clean-burning, renewable sources of conveniently transportable energy. They are carbon- emitting energy sources but are cleaner than coal. The technology is still being perfected, but the fact that most cars in Brazil run on an 85/15 blend of ethanol and gasoline is an indication that these renewable sources of energy may be a part of the transportation future.
Technical and social questions regarding biofuels include, what plants will be the sources of energy? The easiest source to process, and thus the first to come onto the market, was sugarcane. One problem with using sugarcane to produce fuel is that it takes prime agricultural land to grow sugarcane, land that could be used to feed people. Will we one day face the choice between driving or feeding people? It takes energy to run the tractors and make the fertilizer to grow corn or sugarcane. Is the energy output more than the input? With sugarcane there is probably a net gain in energy. With corn, if you count the energy required to produce the fertilizer, then there is a net overall loss of usable energy. Without federal subsidies to farmers in the United States and ethanol import taxes, corn-based biofuels may not turn out to be profitable in the United States where farming costs are high. The other important issue for sustainability is that growing biofuels competes with food production, contributing to higher global food prices.
For about 100 years people have tried to produce a biofuel that targets the cellulose in plant cells rather than the glucose. If “cellulosic” biofuels became practical, then entirely new sources of fuel would be available, using wood waste, paper pulp, and other current “waste products” to supply energy needs. Unfortunately, it is technically difficult.
In summary, all of the various forms of energy available to power human activities have advantages and disadvantages. How to evaluate these trade-offs is a complex, often technical, problem. Since the discussion must take place in the political arena, which can limit the depth and quality of the discussion, completely rational energy policy is seldom achieved. These policies, however, do influence how the state and country address global environmental issues that cannot be solved by one country alone.
GLOBAL ENVIRONMENTAL CHALLENGES
Climate Change
The most pressing global environmental problem facing humans today is human-induced (anthropogenic) climate change. Atmospheric and climatic change can be natural phenomena. The ancient atmosphere of the Earth before the advent of green plants contained very little oxygen. The evolution and rise to global dominance of photosynthetic plants completely changed the global atmosphere by emitting oxygen and raising the concentration of oxygen in the atmosphere to 20 percent. This global atmospheric shift was one of the major turning points in the evolutionary history of the Earth, transforming the air in a way that eliminated many organisms while it made the planet hospitable to others. The global climate has a long and complex history of dramatic changes, with cold glacial cycles alternating with warm interglacials. The North American continent has at times hosted tropical forests, been buried under sheets of ice nearly a mile thick, and been a desert so dry it supported virtually no plants or animals. However, the anthropogenic causes of modern climate change are acting on a much faster time scale than natural climate-changing events in the past.
The greenhouse effect is a complex insulation event. Gasses in the atmosphere, especially carbon dioxide, methane, and nitrous oxide, trap heat coming from Earth’s surface. More specifically, carbon molecules in the atmosphere absorb and reradiate heat escaping Earth’s surface and headed for space. By continually reradiating heat, carbon molecules in the atmosphere regulate the temperature ranges on the surface of the planet. As the concentration of carbon in the atmosphere increases, this greenhouse effect increases. Lowering concentrations of these gasses would allow more of the heat to escape out to space. High concentrations mean more heat is trapped. This trapped heat raises global temperatures, changing precipitation regimes and the timing of the seasons.
Since the beginning of the Industrial Revolution human production of carbon dioxide has increased dramatically. By looking at ancient ice cores and examining air trapped in the ice, scientists have been able to demonstrate multiple patterns of chemical change in the atmosphere over the last 60,000 years. One of the clearest and most important is the increase in the concentration of carbon dioxide in the atmosphere. This increase has been produced largely by removing carbon-rich compounds (fossil fuels) from long-term storage in the ground and burning them, releasing CO2 at a faster than natural rate. Climate scientists and common sense indicate that we need to dramatically reduce our greenhouse gas emissions to avoid catastrophically altering the global climate.
Global warming is underway and its impacts are being felt. Effects of global warming include
Sea level rise
Shrinking glaciers
Changes in the range and distribution of plants and animals
Lengthening of growing seasons
Thawing of permafrost
More extreme weather events
The greenhouse effect. The atmosphere protects organisms from solar radiation, and it insulates the planet from heat loss. Courtesy of the State of Washington Department of Energy
The questions that remain are, how quickly will the temperature rise and how high will the temperature go? Thus far, the news has not been good. Temperatures have risen faster than scientists had predicted. This is in part because there are climate processes acting to accelerate global warming and in part because greenhouse gas emissions have increased faster in the past five years than expected.
While there are efforts in California and elsewhere to limit emissions of CO2 and other greenhouse gases, much more must be done to slow the growth of these global warming agents in the next two decades. The required changes include altering the sources of energy, from carbon- emitting to non-carbon-emitting sources, as well as changing patterns of activity and consumption.
The United States is currently the largest producer of greenhouse gases per capita. While China is the largest emitter overall, citizens of highly developed, urbanized countries have a far greater per capita impact on the atmosphere than people in less-developed countries. China and India, with about half of the world’s population, currently emit far smaller amounts of greenhouse gases per person than the United States or the industrialized countries of western Europe, but they are on a trajectory to overtake us in this regard. This is an alarming prospect, since the multiplication of the huge numbers of people in less-developed countries by the high consumption rates of the most-developed countries is a recipe for climate disaster if technology or usage patterns do not change. To meet its energy demands, China currently depends largely on burning coal. China has the largest reserves of coal in the world, and China already uses more coal than the United States, the European Union, and Japan combined. Every two weeks another coal-fired power plant large enough to serve all of the households in Dallas or San Diego opens in China.
Carbon dioxide emissions from human industry have increased dramatically since 1850 and have increased exponentially since 1950. Data from the Oak Ridge National Laboratory. Used with permission from the National Energy Education Development Project, www.need.org
This NASA data shows steadily increasing global temperature (as temperature change) since 1880, with no reversal on the horizon. Used with permission from the National Energy Education Development Project, www.need.org
Clearly more-developed countries need to be cooperating with rapidly developing countries, helping them find technological ways to avoid burning coal, and working together to dodge the climate change bullet. However, increased emissions from giants like China are not a foregone conclusion. Efforts are underway to help developing economies go directly to cleaner energy generation. The combination of new technologies, regulations to drive reduction of emissions, and changes in consumption and behavior will all be necessary to achieve the very ambitious reduction goals necessary to confront this dangerous global threat.
Climate Change in California
Warmer temperatures will fundamentally change the distribution of vegetation and animal populations in California, as well as affect agriculture and the integrity of shoreline construction and tidal ecosystems. Though sea levels will rise globally, off the coast of California the sea level rise could be less than the global average, as changes in winds and hence ocean currents may move some of the water offshore. Warmer and more acidic oceans will alter marine ecosystems. Coastal fog will respond to changes in ocean and land temperatures, which will affect terrestrial ecosystems dependent on it, but for now the direction of these changes is hard to predict.
While it is clear that temperatures in California will rise, changes in rainfall across the state are harder to predict. Precipitation patterns will shift, as will the seasonality, frequency, and intensity of rainfall. One thing is certain: we will no longer be able to rely upon the Sierra snowpack to provide water-holding capacity, as snowpacks are not expected to survive the increasing warmth of the twenty-first century. In fact, the expected decrease in snowpack could be as large as 25 percent by 2050.
As a consequence of early snowmelt in the spring, soils will dry earlier and require irrigation earlier. Heat wave days are projected to increase by 20 to 30 days per year in the Central Valley, and using water for heat protection may not be possible. This will have consequences for both California’s ecosystems and its agriculture. Changes to the fire regime are expected, with an increase in catastrophic fires.
Many parts of the state already feel water stressed, but with climate change and land-use changes, there will be a dramatic decline in the availability of freshwater. Already, Lake Mead has a water deficit of 1 million acre-feet per year, and some scientists have estimated that there is a 50 percent chance that Lake Mead will be seasonally dry by 2025. Much of California relies on river water. Expected changes in the frequency and severity of weather will affect the amount and character of the water runoff from California’s rivers. With these precipitation changes, there will be changes in the timing and intensity of stream-flow. More intense rainfall in winter could lead to increased flooding and landslides, less infiltration into soils, and streams that could carry greater sediment loads.
The impacts of climate change are numerous. A 2008 UC Berkeley study found that the economic damage to the state due to global temperature increases — including water resources, energy, tourism, recreation, real estate, agriculture, forests, fisheries, transportation, and public health — could have an annual price tag of between $7.3 and $46 billion, and that $2.5 trillion of real estate assets would be at risk from extreme weather events, sea level rise, and wildfires.
Global warming’s projected impacts in California include the following:
Sea level rise, coastal flooding, and coastal erosion: As sea level rises, erosion along California’s coastline and saltwater intrusion into the delta and levee systems will increase, threatening wildlife and drinking water.
Higher risk of fires: Climate change makes forests more vulnerable to fires by increasing temperatures and making forests and brush drier. Today’s fire season in the western United States already lasts for 78 days. The frequency and size of forest fires is likely to increase, perhaps severalfold, by the end of the century.
Damage to agriculture: By reducing precipitation, raising temperatures, causing flooding, and increasing the risk of pest infestations and other calamities, global warming poses a threat to the California agricultural industry, which generated $39 billion in revenue in 2007.
Increased demand for electricity: Higher temperatures and more heat waves will drive up demand for cooling in the summertime.
Public health impacts: As temperatures rise, the number of days of extreme heat events will increase, causing increases in the risk of injury or death from dehydration, heatstroke, heart attack, and respiratory problems.
Impacts on low-income and minority communities: Global warming’s impacts are likely to disproportionately affect low-income and minority communities in California, who have the least ability to resist and adapt to the impacts of higher temperatures, heat waves, floods, and other extreme weather events.
Habitat modification, destruction, and loss of ecosystems: Climate change will adversely affect plant and wildlife habitat and the ability of the state’s varied ecosystems to provide clean water supplies, wildlife, fish, timber, and other goods and services important for human well-being. These impacts are already occurring: the lower edges of forests in the Sierra Nevada have been retreating upslope over the past 60 years. In Yosemite National Park, certain small mammal taxa are now found at higher elevations compared with earlier in the century. Butterflies in the Central Valley have been arriving earlier in the spring over the past four decades.
Water shortage: The Sierra snowpack, which provides up to 65 percent of California’s water supply, will be reduced by at least 25 percent by 2050. In addition, the sea level rise could inundate the Sacramento-San Joaquin Delta with salt water, threatening the water supply for 25 million Californians and millions of acres of farmland.
Flames of the Simi Valley fire ravage a Southern California mountainside. US Air Force photo by Senior Master Sgt. Dennis W. Goff
Californians will be challenged to develop adaptations to these changes, find innovative solutions to the problems that are already becoming manifest, and create a new model for business and culture. Part of that adaptation will be reducing our reliance on carbon-producing energy sources and beginning the transition to lower-carbon- emitting forms of energy. In this respect, California has been a national leader. In 2006, the state legislature set a goal to reduce carbon emissions to 80 percent below 1990 levels by the year 2050. This will take dramatic actions in every sector of society and, predictably, the law has been under attack since its passage.
We need to make changes collectively and as individuals in our own homes in order to stave off rising temperatures and to improve our resilience to expected change. Protecting our natural resources, such as forests, watersheds, and natural areas, is an essential step in ensuring that we can continue to rely on the goods and services nature provides society and that species will have a chance to persist. Many changes in energy, agriculture, and environmental policy are needed to prevent future climate-related disasters. Californians are in a good position to make these changes. We already lead the nation in energy efficiency, and as early adopters of new technologies and ways of thinking, we can continue to take a leadership role in climate change adaptation.
Projected global warming impacts for California for 2070 – 2099, as compared with 1961 – 1990. Compare individual lines across colors to see what may happen with a range of projected scenarios. Courtesy of the California Department of Energy, reflecting the understanding in 2006 about potential impacts
Most Americans, including most Californians, use far more energy than we really need and can start to reduce consumption with relatively small changes to our lives. As the world’s wealthiest nation and the largest emitter of greenhouses gasses per capita, the United States must take a leadership role in reducing greenhouse gas emissions and modeling a less consumptive lifestyle.
Ozone Depletion
Like oxygen (O2), ozone is a molecule consisting only of oxygen atoms, but with three instead of two oxygen atoms (O3). At ground level, ozone is a pollutant that is most commonly produced by automobiles. Ozone also exists in small quantities high in the stratosphere, where it provides a vital function: it protects the surface of the planet from ultraviolet radiation. In the 1920s Thomas Midgley, a chemist, was working on creating a substitute for the dangerous gasses then used as refrigerants. He created a new class of synthetic molecules called chlorofluorocarbons (CFCs). CFCs had many advantages over the previously used chemicals and were quickly adopted for all kinds of industrial and household applications, most notably as refrigerants. Half a century later, it was found that CFCs had the unfortunate property of rising through the atmosphere to the upper layers of the stratosphere, where they are broken down by light to form chlorine atoms. In the stratosphere, chlorine reacts chemically with ozone, with the effect of destroying the ozone. Essentially, CFCs were found to be destroying the ozone layer. CFCs are also wonderful heat sponges. When in the troposphere, they are roughly 10,000 times more efficient as greenhouse gasses than carbon dioxide!
The good news is that CFC production and use have been banned since 1990 by signatories to the Montreal Protocol, and this global response has been effective at dramatically reducing CFC use and impact. Other compounds, including those with bromine, have been found to have the same effect of destroying ozone in the stratosphere, and current efforts focus on ODCs — ozone-depleting chemicals. The worldwide reaction to solving this problem may be the first example of a global political response to an environmental threat. It is an example that can give us courage and confidence in confronting the even larger problem of climate change.
Dead Zones, Fertilizers, and Manure Management
Dead zones are low-oxygen areas in the world’s oceans and lakes. Oceanographers first began noting dead zones in the 1970s. Dead zones are caused by a process called eutrophication in which excess waterborne nutrients stimulate excessive plant growth, eventually depleting oxygen from the water. As of 2004, 146 dead zones in the world’s oceans, where marine life could not be supported by the depleted oxygen levels, were identified. Some of these dead zones are small, but the largest dead zone covers about 70,000 square kilometers. Currently one of the most notorious dead zones is a 22,000-square-kilometer region in the Gulf of Mexico where the Mississippi River discharges into the Gulf. The Mississippi collects water and agricultural runoff from the breadbasket of the world, the American Midwest, and delivers it to Gulf waters. Because of the high concentration of fertilizer use in this region, combined with animal waste from dairies and stockyards, the waters of the Mississippi are unnaturally high in nitrogen and phosphorus. The high nutrient load of the runoff from this vast drainage basin has devastated the regionally important shrimp fishery of the Gulf.
Dead zones can be reversed. The Black Sea used to have the largest dead zone in the world, but it disappeared between 1991 and 2001 when the collapse of the Soviet Union caused a dramatic reduction in fertilizer use.
Manure management will be an increasingly important problem on spaceship Earth. In addition to poisoning rivers with nutrients, cattle, pigs, and their excrement have a role in global warming. The normal method of composting animal waste creates methane gas, the same kind of gas used for electricity generation and heating. Methane is a potent greenhouse gas, over 20 times more efficient at trapping and reradiating heat to Earth’s surface than carbon dioxide. Clearly the day has arrived when we can no longer afford to regard our atmosphere as a global dumping ground for methane, ozone, carbon dioxide, and other gasses.
Agricultural Issues
California is the nation’s agricultural powerhouse. California farms produce nearly half the vegetables, fruit, and nuts grown in the United States, and a number of California crops — such as almonds, artichokes, olives, walnuts, and figs — are commercially produced nowhere else in the country. California is also the nation’s largest dairy producer and supplies vast amounts of other farm products, including greenhouse and nursery products and cattle. Simply put, California is the leading agricultural producer in the United States in terms of cash farm receipts.
Of the state’s 100 million acres, 25.4 million acres (25.4 percent) were dedicated to some form of agriculture in 2008. As vast as that amount sounds, the number of acres in some kind of farm-related activity has been falling in recent years, and California farms are on average quite a bit smaller than the national average: 312 acres for California farms, down from 314 in 2007 and versus 418 nationwide. The Mediterranean climate, freshwater resources, and soils found in California allow for higher intensity of production compared with other parts of the country.
Like so many concerns in California, agricultural land issues and pressures reflect the complexity of the state as a whole. Population growth, land use, immigration, worker safety, water wars, nonpoint source water pollution, carbon credits, and many other disparate issues find their nexus in California agriculture.
One of the most pressing concerns for California farms is the development and conversion of farmland for urban uses. As the state’s population has expanded and land prices have risen, pressure has grown to convert existing farmland into housing developments and other commercial uses.
A 2010 news release from the USDA Natural Resources Conservation Service states, “California has converted 2.1 million acres to urban uses between 1982 and 2007. At the same time, losses were experienced in cropland (900,000 acres), rangeland (1,600,000 acres), and forestland (500,000 acres). . . . The loss of prime farmland, those soils best suited to produce food with the fewest inputs and the least erosion, is particularly troubling and California ranks fourth nationwide in losing such soils between 1982 and 2007. However, between 2002 and 2007 the loss of prime farmland in California stabilized and even experienced a minute increase” (www.ca.nrcs.usda.gov/news/releases/2010/nri_5-4-10.html).
Since many cities in California are located adjacent to prime cropland, urban expansion, particularly exurban development, directly reduces the farmland base. Throughout the Central Valley, about 30,000 acres are converted annually from farmland to urban uses, and California could lose nearly 5 million acres of agricultural land if these lands continue to be converted to urban uses at this rate.
Water Use
Conflicts between residential water needs, environmental water needs, and agricultural water needs have been evident in California for decades. Estimates vary, but all indicate that agriculture uses a substantial amount — more than 50 percent and as much as 90 percent by some estimates — of the state’s freshwater.
Delivery of that water is one of the most interesting parts of the California agriculture water story. Much of the farm and ranch land is located in the drier, southern half of the state. Most of the water falls in the north. A high percentage of the water used in Southern California comes from Northern California through a remarkable system of aqueducts and dams. This water delivery system has allowed farms to flourish in areas that would not be able to support commercial agriculture if the farms had to rely solely on local water sources. This system is financially supported by the federal and state governments and results in water subsidies that primarily benefit the largest industrial growers.
Water use by agriculture can trigger ecological concerns. For example, in many parts of coastal California, agricultural water needs during the summer are met by diverting stream water and tapping groundwater resources, which has led to documented decreases in stream flow during the dry season. This has consequences for salmon — including sudden drops in water level, higher water temperatures, and changes in the invertebrate prey base — that imperil their ability to reproduce. In dry years, excessive pumping from wells and springs can collapse aquifers or cause saltwater intrusion. In addition, ground and surface water can be contaminated by surface runoff of fertilizers and pesticides, polluting the water. Construction and maintenance of buffer zones of native vegetation next to water sources can help to mitigate this problem.
Sustainable Agriculture
How agriculture is practiced can make a big difference in its impact. Practices common to large-scale agrobusiness can take a toll on both the land and the people working it, including loss of topsoil, depletion of soil nutrients, groundwater contamination, the loss of small and medium-size family farms, and poor conditions for farm laborers.
To address these issues, sustainable farming systems strive to promote environmental health, economic profitability, and social and economic equity through stewardship of both natural and human resources. In sustainable agriculture, a diversity of crops and livestock are grown and are selected for their suitability to the site. Cultivation techniques are chosen for their ability to conserve and enhance the soil, as well as protect water resources and wildlife habitat. Natural pest management and other farming methods that minimize synthetic inputs are preferred. Animals may be integrated into the cultivation regime, and animal and other wastes may be utilized on-site. Humane treatment of animals is a core value. In addition, sustainable agriculture seeks to enhance the economic viability of small and medium-sized family farms and their communities and ensure worker safety.
Agriculture and Carbon Sequestration
Climate change in California is likely to have significant impacts for agriculture, including a less reliable water supply and a shift in where certain crops can be grown. For example, according to research done at UC Davis, some areas, such as Yolo County, will become too hot over the next 50 years to grow crops that many farmers rely on, such as tomatoes and cucumbers. California agriculture, however, can also be part of the solution by curbing emissions from tractors, reducing or capturing methane produced at dairy and cattle operations, and using sustainable farming techniques.
Carbon sequestration has been suggested for providing income and incentives for keeping land in agricultural production. The EPA lists four practices that can increase carbon storage in agriculture:
Conservation or riparian buffers for maintaining and restoring vegetation strips along streams and adjacent to croplands
Conservation tillage, in which a portion of the crop residue remains on the soil after planting, including no till, ridge till, minimum till, and mulch till
Modifications to grazing regimes or rotational grazing
Biofuel substitution: substitution of crops or trees grown for biomass rather than food production purposes
According to the USDA Economic Research Service (ERS), if practices like these and others (such as the use of winter cover crops) are adopted, there is the potential to increase carbon storage significantly; somewhere between 29 and 208 million additional metric tons of carbon could be stored each year in US soils. And the ERS notes that these numbers do not include the impact of converting less productive farm and range lands to forests or wetlands, ecological communities that have the potential to sequester carbon.
Air Quality
There are several types of air pollutants of interest to naturalists in California, including smog, particulate matter, sulfur dioxide, carbon monoxide, and carbon dioxide.
Smog in western states is mostly ozone, formed from nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight. NOx comes from combustion sources such as vehicles and power plants and from soil fertilization. VOCs come from such sources as evaporating fuel, vegetation, and consumer products. Ozone is worst on warm, stagnant days. Although originally confined to urban basins such as Los Angeles, ozone is now distributed regionally and is transported between continents. For example, rural areas in far northern California receive some ozone from plumes that travel across the ocean from Asia and make landfall. Ozone causes difficulty in breathing, worsens asthma, and over long periods, reduces lung volume. It also damages plants by reducing photosynthesis, growth, and root development. Many plants exhibit a bronze speckling on the upper leaf surface when exposed to ozone.
Particulate matter can consist of many chemical constituents that come from diverse sources, including wood burning, diesel engine emissions, and road and agricultural dust. Soot in smoke is a fine particle that may be carcinogenic and degrades visibility. Fine particles have been linked to premature death, particularly in vulnerable populations of the old, young, and unhealthy, primarily through worsening cardiovascular symptoms. In general, particulate matter is not damaging to vegetation, though when it contains nitrogen, it may serve as a fertilizer (even leading to harmful nitrogen saturation of ecosystems) when it deposits on vegetation. Exceptions are cement dust, which is alkaline and corrosive, and materials like heavy metals (lead, copper, mercury) which when present can be harmful to grazing animals and consumers of milk and meat. Most particulate matter is in the form of fine particles, including sulfate particles that come from coal-fired power plants.
Sulfur dioxide (SO2) comes from burning fuels, such as in coal-fired power plants, which contain sulfur. SO2 is very irritating to the airways, may trigger asthma attacks, and when oxidized to sulfuric acid, contributes to acid precipitation. Acid precipitation may acidify lakes, particularly in granite landscapes such as the Sierra Nevada where natural pH buffering is weak. Oxidation to sulfate particles is a principal cause of visibility degradation in areas where coal is burned for power or industrial processes. This is more of a problem in the east, though visibility in the Grand Canyon is impacted by sulfate particles.
Carbon monoxide is a by-product of incomplete combustion, whether in automobile engines or from campfires or other biomass burning. It may accumulate, for example, in valleys with little air movement, in caves, and in enclosed tents or automobiles. It causes headache and chest pains and can lead to rapid death in humans but surprisingly is not harmful to plants.
Carbon dioxide (CO2) is also considered an air pollutant. It comes from combustion, in California mostly from vehicles, as well as from many natural processes, including animal respiration.
Warmer temperatures due to climate change will lead to worse ozone air pollution in many places, because more VOCs are emitted at warmer temperatures from plants and evaporating fuels, and because the reactions that form smog increase with temperature. Many of these changes will also increase the risk of wildfire and extend the fire season in California, thereby temporarily but significantly increasing particulate matter and ozone concentrations in communities downwind of the fires.
Solid Waste
In nature, there is no such thing as waste. A tree dies and as it decomposes, it becomes food for fungi, a home for insects and birds, and later, a seed log for new trees. In human society, however, people treat materials as if they can “go away,” and we excel at producing waste. The average American generates approximately 30 pounds of trash per week. That’s about 1,600 pounds of trash a year for every person in the country. But what happens to that trash? How much of it could have been recycled, reused, or composted? And where did it come from in the first place?
Every item you buy has something called “embodied energy.” Embodied energy is the energy that was used to get the product from its source to the consumer: to extract the resources the product is made from (wood from logged trees, plastic from petroleum extraction, etc.); to manufacture, package, and advertise the product; to ship it from the manufacturer to the store and then to the home; and finally to collect it for recycling or landfilling. For every product in your house, a certain number of gallons of gas and water were used to create, transport, and dispose of it. When we fail to use something to its fullest potential, we are wasting not only the materials comprising the product but the resources that went into creating it.
Typically, when items are thrown away, they go first to a transfer station or materials recovery facility where they are sorted and recyclable items are removed from the waste stream. The rest is trucked to a landfill. A landfill is a gigantic hole that is lined with clay or plastic to prevent leakage into the soil and groundwater. Problems associated with landfills are numerous: landfill space is becoming more scarce, and many have been closed because of groundwater contamination. Building new ones is getting harder: few people want a landfill located near their house, and increasingly, the land is wanted for other purposes such as housing and open space. For these reasons, many cities now truck their garbage far away at great expense. The City of San Francisco hauls all of its trash over 50 miles to the Altamont Landfill in Livermore, CA, and Los Angeles and other Southern California cities are actively considering long rail hauling of their garbage for disposal in the Mojave Desert.
Students work to maintain a compost bin. Photo used by permission © Regents of the University of California
Materials in landfills are covered daily with soil to shield them from rain, wind, sun, and air. The result is that many things in a landfill take decades, if not hundreds or even thousands of years, to decompose. A plastic bag may take between 500 and 1,000 years to completely break down. As the materials do degrade, landfills emit a powerful greenhouse gas: methane. Although many landfills now are set up to recover some of this methane gas and use it for productive purposes, every ton of methane that escapes into the atmosphere has over 20 times the greenhouse impact as one ton of carbon dioxide. Food waste, yard debris, and other organics are the biggest generators of methane, amplifying the importance of composting. Some states have actually banned organic materials from their landfills.
Due to diminishing landfill space and concerns about conservation of resources, California has instituted laws to reduce waste and encourage recycling, and recycling rates in California have improved dramatically in recent decades. But despite these improvements, Californians still throw away about a third of their bottles and cans and recycle less than half of the paper they use.
Does it really matter? Yes. Reuse and recycling are not just about conserving resources. These actions also directly reduce carbon emissions and help in the fight against global climate change. The EPA states, “Harvesting, extracting, and processing the raw materials used to manufacture new products is an energy-intensive activity. Reducing or nearly eliminating the need for these processes, therefore, achieves huge savings in energy. Recycling aluminum cans, for example, saves 95 percent of the energy required to make the same amount of aluminum from its virgin source, bauxite. The amount of energy saved differs by material, but almost all recycling processes achieve significant energy savings compared to production using virgin materials” (http://epa.gov/region4/recycle/faqs.htm).
Right now, there are masses of garbage, mostly plastic, swirling around the world’s oceans. The largest garbage mass is in the Pacific. It is nicknamed the Great Pacific Garbage Patch. Due to difficulties in measuring it, its exact extent is not known, but it is likely as large as the state of Texas and probably much larger; in some places, it extends 10 feet below the surface. The plastic breaks down into tiny pieces that make it hard to study or clean up but easy for sea life to mistake for food. Scientists say that 80 percent of the garbage is from land sources — packaging and plastic bags left on beaches, blown from a highway to a storm drain or littered near a creek. It is astonishing to consider, but this mess has a greater mass than all of the plankton available in the northern Pacific Ocean and is now a permanent and very damaging part of the aquatic food chain. For these and other reasons, many communities and even some countries like Ireland have banned plastic bags.
Fortunately, there are ways to ameliorate this situation and prevent others like it: The four R’s — reduce, reuse, recycle, and rot (compost). The four R’s are just a way of seeing products as a part of the natural material cycle and recognizing that there is no “away.” These practices apply to more than just paper, bottles, cans, and banana peels. Computers, cell phones and other electronic devices, tires, and construction and demolition debris can all be recycled. We can draw inspiration from the cities of Oakland and San Francisco, both of which have set the exciting and ambitious goal of generating zero waste by 2020. They join cities and counties all over California and the world in passing resolutions to achieve this goal.
Here are some tips for reducing your trash footprint:
Buy less. Buy only what you really need and intend to use or keep.
Buy products with little or no packaging. Refuse a bag if you don’t need one.
Try items that can be reused: cloth bags for shopping, cloth napkins for meals, dish towels for the kitchen, and reusable cups for that cup of coffee on the run.
Buy toys, clothes, and furniture that are gently used. Garage sales are fabulous for this.
Donate used electronics or recycle them. Note: Electronics usually contain hazardous materials and are important to dispose of properly!
Choose durable items that will last. Avoid items designed to be used only once.
Buy or build a compost bin. Composting is recycling at your home. There are no transportation costs, and you get a useful product for your garden!
Buy recycled products. Without a market for recycled paper or reclaimed lumber, the recycling system comes to a grinding halt.
For a complete list of household items that can be conveniently recycled in California, as well as information about recycling of electronics and hazardous waste, visit the website of CalRecycle at http://www.calrecycle.ca.gov.
Population
All of the problems mentioned above are, in one way or another, outgrowths of the size of the human population and the amount of resources we each consume. Human population grew slowly for most of the 200,000 years that Homo sapiens has existed as a species, probably hovering for most of that time at about 5 million people. The invention of agriculture about 11,000 years ago led to the first major spike in human numbers, as well as population centers, career specialization, and rapid cultural and technological advances. The following 9,000 years saw human population expand from around 5 million to about 200 million at the time of Christ. Another millennium and a half brought another increase in human numbers, to an estimated 500 million in 1650. Human population reached 1 billion in 1830, stood at 2 billion in 1930, and reached 3 billion by 1960. We reached the fourth billion 14 years later (1974), 5 billion by 1987, and 6 billion in 1999, and we are now over 7 billion as of October 2011.
Predictions about the future provide a mixed report. The United Nations notes that while the world population growth rate has fallen to 1.2 per cent, “nonetheless, world population will continue to increase substantially during the twenty-first century. United Nations projections (medium fertility scenario) indicate that world population will nearly stabilize at just above 10 billion persons after 2200. However, the twenty-first century is expected to be one of comparatively slower population growth than the previous century, and be characterized by declining fertility and the ageing of populations” (http://www.un.org/esa/population/publications/sixbillion/sixbilpart1.pdf).
The population of California is approximately 38 million and is expected to increase in size by more than 22 percent to 46,720,307 by 2025. The increase will be driven by a combination of both births and immigration.
Most of the state’s population is concentrated in coastal counties. However, the areas with most rapid growth are projected to be in inland counties. Populations of inland counties could show a 45 percent increase in the next 20 years compared with an increase of 17 percent in coastal counties. However, 60 percent of the population will still be in coastal counties through 2040, and with dramatic rises in inland summer temperatures due to climate change, these areas may be less likely to be able to support large numbers of people and the current agricultural economy.
The age distribution of the population will shift dramatically. In particular, the proportion of seniors age 60 and older in the population will increase from 14 percent of the population in 2008 to 24 percent of the population in 2030, and the proportion of those 20 years old and younger will decrease from 30 percent in 2008 to 27 percent of the total population in 2030. The ethnic makeup of California is also expected to change between 2008 and 2025. The Hispanic population is expected to grow and will constitute a majority by 2040. Asian populations are also expected to grow. By 2025, 30 percent of the state’s population will be foreign born. As the state changes ecologically and culturally, it will be increasingly important to find common cause with all Californians in our approach to preserving our intimate link with the environment.
The wonderful and terrifying thing about living on Earth in the twenty-first century is that we have powerful tools that make it abundantly clear that we live on one planet, with nowhere else to go. Virtually everyone has now seen images of the Earth from space, showing a blue sphere rotating in a huge, black void. We are rapidly reaching the limits of human population and resource use that the planet can support. We are creating global environmental dangers that no previous generation has seen or been challenged to solve. We also have unprecedented technological tools to perceive, communicate about, and potentially overcome these problems that no previous generation has possessed. A classic Chinese curse is to wish that one’s enemy “live during interesting times.” The connotation is that tranquil, ordinary, peaceful times are less “interesting” than times of turmoil and upheaval. The next 100 years promise to be a most interesting time.
Explore!
VISIT A POWER PLANT AND FIND OUT WHERE YOUR POWER COMES FROM
Call your local power company and ask where your power comes from. Your power is likely to come from multiple sources, so find out if any of the power plants are local and if you can go see them.
visit your local landfill or transfer station and find out where your trash goes
The location can usually be found in your phone book. Be sure to ask where the materials go if they leave the site. If it’s a landfill, see if you can find out how old it is and how full it is.
Both power plants and landfills are large operations and may require permission to visit. However, the operator of the site may have a public information officer who can help you.
VISIT A LEED CERTIFIED BUILDING OR TAKE A GREEN HOME TOUR
You can find a list of projects certified by the Leadership in Energy and Environmental Design (LEED) at the US Green Building Council’s website, www.usgbc.org, under Project Profiles. The new California Academy of Sciences in San Francisco is LEED certified and even has a living roof. Green home tours in Northern California can be found at http://www.builditgreen.org/green-home-tours.
CALCULATE YOUR CARBON FOOTPRINT
Go to the websites below and calculate your carbon footprint, then identify three things you can do to reduce it.
http://www.carbonfootprint.com/calculator1.html
http://www.epa.gov/climatechange/emissions/ind_calculator.html
DO A DUMPSTER DIVE !
How does your household garbage stack up? Write down everything you think you would find in your garbage can over the course of a week. Be specific and try to assign percentages, such as paper 10 percent, plastic 20 percent. Then actually go through your garbage the day before it’s picked up and sort it by material. (Use gloves and goggles.) Then ask yourself, how much of this could have been recycled? How much composted? Why did I buy this product in the first place? Did I use it fully or even need it? How many of these items were disposable and in use for less than one day? One hour? Could I have bought something similar that could have been reused, recycled, or composted? In the following week, see what you can do to cut the waste stream by 50 percent. Then see if you can maintain the lower production of waste.
MAKE YOUR OWN WORM BIN!
You can easily make your own worm bin and start composting kitchen scraps for future use in your garden. Every bucket of kitchen waste that gets composted is a bucket that isn’t transported to and buried in a landfill!
Directions can be found at
http://www.gardensimply.com/howto/wormbin.shtml
http://whatcom.wsu.edu/ag/compost/Easywormbin.htm
http://www.stopwaste.org/home/index.asp?page=445#plastic
LEARN ABOUT YOUR FOOD
The carbon impact of food is not restricted to the land on which it is grown. Growing food sustainably may sequester carbon, but processing it and shipping it emits carbon. Do some research on your food. Go to your kitchen and make a list of the countries your food items come from. For packaged foods, look for small print near the ingredients list for “Product of X.” The international origin of many unlikely foods — crackers, cereal, canned goods — may surprise you.