A DOCTOR ENTERS AN EXAM ROOM WITH A FOLDER, LOOKING grave. “I’m very sorry to tell you this,” he says, “but you have been diagnosed with lung cancer.”
The patient in the room turns white with fear. “Oh no!” But the doctor quickly offers some reassurance, saying, “Don’t worry, we caught it relatively early. Your cancer is stage I, meaning it has stayed small and remains only in your lung and has not spread to other parts of your body. There is a fairly good prognosis with your type of malignancy.”
The patient begins to breathe a little easier. “Wow, okay, that’s a bit of a relief. What’s the treatment? When does it start?”
The doctor gives a condescending guffaw. “Oh no, we’re not going to treat your cancer. You see, we haven’t figured out completely why the cancer formed, and we can’t treat it effectively in every patient; really, there’s still a whole lot of uncertainty around this disease. We wouldn’t dare move forward without knowing every last thing about this; doesn’t that make the most sense?”
This example sounds ridiculous, but it actually mirrors the same “logic” that is trotted out far too often by our elected officials. No honest scientist would ever say his or her field of study is finished, or completely understood. This sounds obvious. We haven’t cured Alzheimer’s, or traveled at light speed through the galaxy, or figured out exactly how life began. Politicians, though, love to seize on the lack of utter, complete, 100 percent proof in scientific fields as a way of delaying or opposing any action on that topic. Meet the CERTAIN UNCERTAINTY: essentially the doctor’s ludicrous argument that since we don’t know it all, we don’t know anything. As you can probably guess, this tactic has been deployed repeatedly and aggressively in the debate over climate change.
Climate science is inherently a muddy endeavor. Scientists are trying to predict what will happen in the future from a variety of clues, such as long-ago changes to the planet’s climate (known as paleoclimatology), computer modeling of what has happened and what will happen, measurements of temperature from many sources, measurements of ice thickness and rate of melting, measurements of sea-level rise and storm intensity and drought and precipitation and so on. The world is a big place, the climate is a complicated beast, and understanding it is not a simple task. But here’s the rub: in spite of all those challenges, we know an incredible amount about the climate and how it is changing.
The assessments of global warming, including the fact that we have already raised Earth’s temperature by about 1°C and that we’re on track for a whole lot more in the coming years and decades, are based on very solid science. The fact that humans have caused virtually all of that warming is also a rock-solid conclusion. These are not guesses. To be sure, like any measurement, what we know about warming does have uncertainty associated with it, but that does not make it wrong, nor does it make acting to mitigate it impossible or foolhardy.
To Republican politicians, though, that is exactly what the uncertainty does. They rely on the careful nature of scientists, who are not afraid to admit the lack of total precision, to push for no action at all. There are many examples, but let’s start where we left off last chapter, with George W. Bush, speaking during a presidential debate in 2000:
Look, global warming needs to be taken very seriously, and I take it seriously. But science, there’s a lot—there’s differing opinions. And before we react, I think it’s best to have the full accounting, full understanding of what’s taking place.1
The idea that we should have a “full understanding” before acting sounds eminently reasonable, which is why politicians have gotten away with this tactic for so long. “Look before you leap” is difficult to argue against, especially to a skeptical public who may not understand exactly what goes into climate science. Before we get into some other more specific claims regarding uncertainty in climate science, here’s a quick counter to the entire argument from cognitive scientist and psychologist Stephan Lewandowsky:
So anyone who says that we shouldn’t act on climate change because of uncertainty is really inviting you to ride towards a brick wall at 80 km/h because it might not hurt. [Do] you feel lucky?2
Well, punk? Do ya?
POLITICIANS DEPLOY THE CERTAIN UNCERTAINTY on several specific climate-related topics. As discussed already, climate science is a broad and complicated field, so there are many specific topics on which one can claim a lack of proof. For a first example, let’s jump ahead from that debate quote by fifteen years and one Bush brother (Jeb):
I don’t think the science is clear of what percentage is man-made and what percentage is natural. I just don’t—it’s convoluted. And for the people to say the science is decided on this is just really arrogant, to be honest with you.3
We’ll ignore the fact that doubting what the entirety of the world’s scientists say on an issue seems a tad more arrogant than those scientists’ explaining what is known. Focus on the message here: the science is not “clear” as to humanity’s contribution to warming; the science is “convoluted.” By casting doubt on what we know, Bush argued essentially that we know nothing. He was, of course, wrong.
Science does, in fact, have a good idea of how much of the observed warming is due to human impacts. Spoiler: pretty much all of it.
Here’s how the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) summarized this question in 2013:
It is extremely likely that human activities caused more than half of the observed increase in [global mean surface temperature] from 1951 to 2010.4
The report added that this conclusion is “supported by robust evidence from multiple studies using different methods.” In other words, we are really sure about this, and there is a lot of evidence for it.
A primary method scientists have for determining what caused a certain climatic phenomenon—in this case, warming temperatures—is called a fingerprint analysis, or fingerprint study. Basically, the idea is to look for the unique mark of certain activities on the climate system—an imprint of humans placed on the world. Scientists do this by comparing what we observe to what the computer models would predict.
Models are complicated computer simulations that try to replicate what goes on in the climate. There are many of these in use by scientists around the world. By allowing researchers to add and subtract elements in their predictions, the models make fingerprinting possible. For example, a model might begin from near the start of the Industrial Revolution (say, around the year 1800) and run through the present day. In one scenario, the model simulates what happens to the climate when humans emit all the carbon dioxide that we really have emitted since then; in another, it simulates the same time period but without the CO2 emissions.
What these studies show is that when you remove human influence from the equation, all the warming we have observed in the real world disappears. No humans, no warming. Here’s a chart from NASA5 illustrating this idea:
Credit: NASA
The lines representing modeled human influence and observations match up extremely well, while the “no human influence” line stays largely flat and even shows a cooling trend (the chart notes some major volcanic eruptions, which have a cooling effect on global temperatures).
The models don’t just look at human CO2 emissions. They include a wide variety of inputs, such as other emissions, like sulfate aerosols (which have a cooling effect, though a brief one), and nonhuman activities like volcanic eruptions and solar activity. And study after study, of a variety of types, have all pointed to humans as the primary cause of the significant warming observed.
The IPCC has tried to estimate specific temperature changes that can be attributed to various of these causes: human greenhouse gas emissions, solar activity, and so on.6 Their answer, in short: humans have caused all the warming we have seen, while natural variability and other causes, such as solar output, account for essentially none of it.
These conclusions, as the IPCC noted, come from a wide variety of sources. Here are just a couple of them: one study, published in the journal Climate Dynamics in 2012, used a statistical method to assess the various contributions to warming. The authors concluded: “The expected warming due to all human influences since 1950 . . . is very similar to the observed warming.”7 Another, published in Nature Geoscience in 2011, combined multiple models to ask similar questions and found that it is “extremely unlikely” that the observed warming could be caused by internal variability—that is, by nonhuman influence.8
Again: the world has warmed, and we did it. It’s us, and essentially nothing else. Yet many politicians continue to parrot the same general message: we don’t know how much the world is actually warming, and we don’t know how much warming is due to human activity; therefore, let’s not do anything about it.
The last part of that argument, that we should do nothing at all, is its own type of the CERTAIN UNCERTAINTY. Here’s Florida senator and 2016 presidential candidate Marco Rubio, appearing on Face the Nation in April 2015:
I believe the climate is changing because there’s never been a moment where the climate is not changing. The question is, what percentage of that . . . is due to human activity? If we do the things they want us to do, cap-and-trade, you name it, how much will that change the pace of climate change versus how much will that cost to our economy? Scientists can’t tell us what impact it would have on reversing these changes, but I can tell you with certainty, it would have a devastating impact on our economy.9
Rubio repeated that same tired refrain, that the human contribution is somehow unknown and unknowable. Then he offered up a particularly brazen version of the CERTAIN UNCERTAINTY: he claimed that scientists “can’t tell us” what would happen if we actually tried to slow warming, and said “with certainty” that taking any actions to mitigate climate change—“cap-and-trade, you name it”—would have a terrible effect on the economy.
Rubio’s claim that indeed it is certain that taking action would destroy the economy bears scrutiny. This is, obviously, more of an economic discussion than a scientific one, but of course understanding the economic effects of climate change requires an understanding of science. And the experts that have actually undertaken this sort of analysis are clear: doing nothing will cost far more than doing something.
The most cited and perhaps most comprehensive analysis of the economics of climate change is now a decade old. The seven-hundred-page “Stern Review,”10 conducted by UK economist Nicholas Stern and released in 2006, had a stark and firm conclusion: keeping global warming to a reasonable level—1.5°C—would cost money, and a lot of it. In fact, it would cost about 1 percent of the entire world’s GDP annually by 2050. But without such actions? The costs would be absolutely devastating, falling somewhere between 5 and 20 percent of global GDP each year.
Other studies have also found huge costs associated with inaction, and surprisingly low costs associated with action. A group at Stanford University led by Mark Z. Jacobson, modeling scenarios in which every state in the United States could transition to 100 percent renewable energy by 2050, has found that such a world would actually cost substantially less than just continuing on our current, fossil fuel–heavy path.11 Jacobson has said that “when you account for the health and climate costs—as well as the rising price of fossil fuels—wind, water and solar are half the cost of conventional systems. A conversion of this scale would also create jobs, stabilize fuel prices, reduce pollution-related health problems and eliminate emissions from the United States. There is very little downside to a conversion, at least based on this science.”12
A study published in Nature in 2015 found that not engaging in such a conversion would have a remarkable effect: a decline in global incomes by 23 percent by 2100.13 One of the study authors, Marshall Burke, also of Stanford, said: “We’re basically throwing money away by not addressing the issue.”14
Virtually every proposed climate-related policy in the United States is met with that same refrain: that it will destroy the economy. When Rubio made his comments, the primary policy bogeyman was the Clean Power Plan, an Obama- and EPA-led regulation designed to reduce emissions from power plants. Opponents of the regulation, which would have the effect of shuttering some coal-fired power plants and making it nearly impossible to build new ones, claim that the costs would be prohibitive. Indeed, some not-very-independent reports found just such problems. A consulting firm called National Economic Research Associates released a report in late 2014 that found a total increase in energy costs of $479 billion over the period from 2017 through 2031.15 Half a trillion dollars!
There are a lot of problems with this report. The most basic appears on the first page, which lists the groups for whom the report was prepared. The list includes the National Mining Association, the American Coalition for Clean Coal Electricity, American Fuel & Petrochemical Manufacturers, and others with more than a little bit of skin in the game. More fundamentally, the analysis ignores a wide variety of factors such as energy efficiency improvements and incentive programs for low-income communities, and it offers very little information about how exactly it arrived at its cost estimates.16
If you ask the EPA itself—which, of course, has biases of its own—the benefits of the Clean Power Plan far outweigh the costs.17 The costs here are technology costs: building new energy infrastructure, retrofitting older plants to reduce emissions, and so on. The benefits are many; for example, by reducing the number of coal plants, a whole host of public health benefits emerge. Along with CO2, those plants emit other harmful pollutants, such as PM2.5, tiny particles that exacerbate asthma, cause other respiratory illnesses, and result in thousands of premature deaths every year. Those outcomes have associated costs, many of which have been quantified.
There are direct climate-related benefits as well, of course; by reducing CO2 emissions, we slow climate change, meaning we slow sea-level rise, reduce the impacts of stronger storms and lengthier droughts, and so on. These things add up! And perhaps the biggest benefit, though easily the hardest to quantify, is the issue of leadership. The United States was the biggest CO2 emitter for many decades, and it remains second only to China; a global agreement to slow climate change requires American—and Chinese, and Indian, and Brazilian, and other countries’—leadership. If the United States couldn’t even take modest steps to reduce its own emissions, how could it argue for the rest of the world to take such steps? The Clean Power Plan gave the United States a strong leadership position on the issue, a position that arguably helped bring about the international agreement signed in 2015 by 195 countries that will hopefully put the world on a path toward slowing warming.
In the end, the EPA estimated that the net benefits—including the technological costs of updating some infrastructure—would come to somewhere between $26 and $45 billion annually by 2030. Put another way, the EPA calculated a dollar number similar to that estimated by NERA, but in the exact opposite direction, with a benefit instead of a cost. The two sides were, incredibly, a trillion dollars apart in their analyses.
Even CitiGroup (which now goes by just “Citi”), not usually considered an environmental champion, has stated clearly that letting climate change happen is a lot worse economically than the alternative. Citi released a study estimating that an “Action scenario” would cost about $190.2 trillion over twenty-five years—a hefty price tag.18 But wait! The “Inaction scenario,” in which we do nothing but continue burning fossil fuels and continue on our current path, would cost $192 trillion; and that’s before the damages due to a warming world are even factored in. Allowing the planet to warm 2.5°C, Citi said, would shave $44 trillion off the global GDP. Letting the increase in temperature go all the way to 4.5°C, which is feasible if we don’t stop emitting soon, would cost $72 trillion. That’s more than four times the current US GDP, and only $5 trillion less than the entire world’s GDP in 2014.
The point is this: Rubio claimed that the economic hardships associated with reducing emissions are written in stone. In actuality, they are—but they are opposite from what the senator said. There is near-universal agreement at this point—except among the industries fighting to stay relevant in a changing world, like coal and oil—that acting strongly to mitigate climate change would have a positive economic effect. Rubio’s CERTAIN UNCERTAINTY leans on the idea that taking action requires a leap into some big black hole of unknowns. In actuality, the science itself is far more certain than uncertain, and the economic impacts don’t even vaguely resemble his assurances.
LEANING ON SUPPOSED UNCERTAINTIES in science is an old trick in political circles. Perhaps the biggest environmental issue of the 1980s, acid rain, lingered for years because of the supposed need for “more study.” The Reagan administration consistently pushed back against any action to curb the pollution that causes acid rain, often claiming that the science was simply too uncertain to justify action. For example, EPA administrator Lee Thomas—with a background not in science, but in criminal justice and public safety, before being appointed by Reagan19—claimed in 1985 that “people want more certainty” that reducing pollution would even have an effect.20 He made the same argument again in 1986:
We do not believe that the current state of [scientific] knowledge can sustain any judgment with respect to the level of emission reductions needed to prevent or eliminate [acid rain] damage. . . . We encourage the Congress to postpone a decision on creating a national acid rain program until it can be based on . . . sounder scientific foundation.21
The argument is clearly recognizable: we don’t know everything; therefore we shouldn’t do anything. And by the time of those comments, Thomas was completely incorrect: we had substantial understanding of how acid rain forms, what it does to the environment, and how reducing emissions would reduce those impacts. For example, a report prepared for the White House Office of Science and Technology Policy and released in 1984, despite accusations of malfeasance on the part of those trying to delay action,22 found a direct relationship between sulfur dioxide pollution from smokestacks and acid rain.
Even more notable was a report released by the National Academy of Sciences in 1983, which found the following: “If emissions of sulfur dioxide from all sources in this region were reduced by the same fraction, the result would be a corresponding fractional reduction in deposition.”23 In other words, cut the pollution, cut the acid rain. It was essentially settled science several years before the Reagan administration’s continued use of the CERTAIN UNCERTAINTY.
THOUGH THE CERTAIN UNCERTAINTY is most often deployed with climate change and related issues, it does rear its head in other scientific arenas as well. For example, in early 2007, Texas governor Rick Perry issued a mandate requiring all sixth-grade girls to receive the human papillomavirus (HPV) vaccine. A few months later, an angry Texas state legislature shot down the governor’s plan, passing a bill in convincing fashion that barred the state from instituting such a mandate. One of the bill’s sponsors was Representative Dennis H. Bonnen; here’s what he had to say about requiring the HPV vaccine:
We did not want to be the first in offering young girls for the experiment to see if this vaccine is effective or not.24
As usual with this type of scientific trickery, the statement sounds eminently reasonable. If we really don’t know that this vaccine is effective, why on earth would we require it of hundreds of thousands of children?
Because we do know that it is effective. At the time, the only HPV vaccine available was Gardasil (others have since been developed and approved). The idea behind the vaccine is to prevent transmission of certain types of HPV (there are dozens of variants of the virus), because HPV is known to be a primary cause of cervical and other cancers. The virus is exceptionally common; the CDC says that “nearly all sexually active men and women get it at some point in their lives.”25 Often the infection is not noticed and dissipates without treatment. Certain dangerous strains, though, raise the risk of cancer dramatically. If the vaccine works and reduces the transmission of HPV, tens of thousands of cancer deaths could be avoided every year.
Now, there is a problem with evaluating a vaccine that prevents a viral infection that can then cause cancer: time lag. The vaccine would ideally be given before an individual becomes sexually active—hence Governor Perry’s mandate regarding sixth-grade girls, at a point when the vast majority have yet to become sexually active—but that means years before an actual signal regarding cancer prevention would become clear. The cancers caused by HPV tend to start cropping up when patients are in their twenties at the earliest, meaning as long as two decades between vaccine administration and any indication of whether cancer was prevented.
That does not mean, though, that we don’t know whether the vaccine works. It actually isn’t very hard to test whether Gardasil prevents HPV itself, and there is also a cancer precursor known as cervical intraepithelial neoplasia, or CIN, that occurs well before the cancers themselves form. And the evidence, even back in 2007, was clear: vaccinating young people works.
Scientists from the pharmaceutical company Merck (which produces Gardasil) presented results of one large trial—the FUTURE II study—in October 2005.26 That study, including more than twelve thousand young women aged fifteen to twenty-six, found an impressively high rate of effectiveness for Gardasil. In the group that received the vaccine, there was only one case of CIN; in the group that received a placebo, there were forty-two such cases, and one case of cervical cancer. Those results add up to a vaccine efficacy rate of 98 percent.27
There was also evidence specifically in younger girls. Another study presented in 2005 showed that girls aged ten to fourteen responded very well to another very similar vaccine. The study resulted in 100 percent of the girls testing positive for antibodies to HPV 16 and 18, the two most important strains of the virus.28 The presence of the antibodies means that the virus would almost certainly not be able to take hold in those girls.29
Soon after Gardasil was approved by the US Food and Drug Administration in June 2006, a federal vaccine advisory panel unanimously voted to recommend vaccination in all girls and women aged eleven to twenty-six.30 This expert endorsement essentially meant that the community of physicians who know best thought that Governor Perry’s mandate was an excellent idea. They believed that there was ample evidence for young girls to receive this vaccine, and that it would undoubtedly save lives. But the Texas state legislature claimed that administering the HPV vaccine was tantamount to experimenting on young girls.
The science was clear back then, and it has only become clearer since: all young people, both boys and girls, should receive the HPV vaccine before becoming sexually active, according to the CDC.31 In the end, the controversy over HPV vaccination had more to do with arguments about sexuality and morality and the like than it did with science. Representative Bonnen’s claim of a lack of knowledge was simply a way to support his ideology. This is another hallmark of the CERTAIN UNCERTAINTY. When you hear a politician use this technique—calling for more research before action is taken, or claiming that the science is unsettled—look at the background for that claim. Does the politician support certain special interests where focusing on uncertainty would help push his or her views? Is an oil company–friendly policy or an abstinence-only puritan ideology at the root of the claim?
Politicians break out the CERTAIN UNCERTAINTY only when it suits them. Remember in Chapter 1, when a long line of members of Congress repeated some version of the idea that the “science is settled” as it pertains to fetal pain? With regard to scientific issues, elected officials pick and choose when to argue that uncertainty is both present and important, and the decision rarely has anything to do with the actual state of the research in that field. It is political opportunism and little else. Science will always have uncertainty. Every measurement, every experiment, every theory and hypothesis, including those proven to within the absolute limits of science and understanding—they all have some margin for error. Pointing that out when it suits a political agenda isn’t an argument; it’s just a smoke screen.