The following remarks were given in at “God Is Great. Is God Green? A Conference on Evangelicals and the Environmental Task.” They are in response to Dr. Roy Spencer’s presentation, “Manmade Global Warming: Science or Religion?” The conference took place in Washington, DC on November 14, 2008.
This is a new audience for me, and so I thought I’d start by saying a few things that don’t fit into the introduction. First, I am a Christian and that certainly influences my views on policy matters, but I don’t think it should influence one’s interpretation of scientific observations or evaluations of scientific theories. So I wouldn’t feel comfortable saying, as Dr. Spencer did in the paper that was presented, that God’s likely to have made the climate system insensitive to human emissions of greenhouse gases. If this is so, then why did God make the ozone layer so sensitive to human emissions of CFCs, a phenomenon that is beyond dispute?
Albert Einstein famously rejected quantum theory, reasoning that God doesn’t play dice with the universe. On one occasion Niels Bohr responded, “Einstein, stop telling God what to do!” And of course Einstein later admitted that he was absolutely wrong about quantum mechanics, which I think illustrates the danger of that sort of reasoning.
Second, I’m not a climate scientist. I’m trained in physics and I followed the literature on climate change for about 30 years, since taking a course on the subject as an undergraduate at MIT. And I’ve taught for about the last fifteen years a graduate course on climate change. But I long ago made the transition from physics to science policy, and so I won’t debate any of the specific scientific points that Dr. Spencer raised. Not because I don’t think that they are debatable, but because I don’t think that one’s attitude toward climate change policy—in particular whether we should be concerned enough about climate change to do something now to reduce the greenhouse gas emissions—is influenced really by any of what was presented.
Dr. Spencer would agree that his is a minority view. I would say a small minority view. And I don’t know if you would call the majority view a consensus, but the large majority, or overwhelming majority, of scientists, as represented by a series of reports by our National Academy of Sciences, involving hundreds of scientists, and the reports of the Intergovernmental Panel on Climate Change, the IPCC, involving thousands of scientists, [holds] that indeed not only is the climate changing, the earth is warming, but the climate is changing in other ways too. But most of that warming, most of that change is due to the increase in atmospheric greenhouse gases that are caused by fossil fuel burning and other human activities, and that unless we change course, this warming will continue.
And I think that one marker is that in the latest IPCC report—and Dr. Spencer mentioned that without feedbacks, I believe the warming would be one degree Fahrenheit—it was judged unlikely that the warming would be less than four degrees, very unlikely that it would be less than three degrees. And the possibility of a net negative feedback wasn’t even considered plausible enough to be listed. And you don’t have to take my word for it. Just Google IPCC, go to the website, download and read the summary for policymakers. Or go further and read the technical summary, or read the whole series of reports.
Now this majority view could be wrong. Or even if it’s right about the past, it could be wrong about the future. Climate may turn out to be less sensitive to concentrations of greenhouse gases than scientists now fear. And I sincerely hope that Dr. Spencer is right and the majority view is wrong. Because if the majority view is right, then we are virtually condemned to severe climate change as a result of the increase in greenhouse gases that we’ve already put into the atmosphere. And the sort of momentum in our industrial system that will certainly carry us further.
But I think we can all agree that the majority view could be correct, and so I don’t think we can avoid considering what our moral obligation is in that light. We don’t have to be sure that a danger exists to take actions to protect ourselves or others. We buy fire insurance for our house, even though the risk of a fire is quite small. We require that cars be equipped with seatbelts and airbags and we may choose, or not, to buckle up. We may choose, or not, to buy a more crashworthy car.
In each of these cases, we weigh the costs and benefits and we take precautionary actions like buying insurance, when we judge that the costs are smaller than the risks of inaction. Now you may say this isn’t the same thing because we have everyday experience with these events happening with other people. And we don’t know for sure that climate is changing or that we’re the cause, or if we’re the cause that it will be much worse in the future.
Perhaps a better analogy, therefore, is the Cold War. Since my defense background was mentioned, I thought I would throw that in. The United States spent trillions of dollars during the Cold War to deter an attack from the Soviet Union, even though we had no proof that the Soviet Union would have attacked the United States or its allies if we had not spent that money. Now you may say that it’s just common sense to protect against such a risk, but I think the risk of climate change is every bit as much common sense.
We know without a doubt that the concentrations of carbon dioxide and other greenhouse gases are increasing in the atmosphere. No one disputes that. We know without a doubt that increase is due to human activities, like the burning of fossil fuels. No one disputes that. We know without a doubt that those gases absorb infrared radiation and warm the surface of the earth. All this was recognized many years ago.
And so, in the meantime, we’ve been steadily collecting data, and the majority of these data—not all of them, and we shouldn’t except that all of them would line up in the same direction, because the climate system is so complex—are in accord with the theory that human emissions of greenhouse gases are the cause of this warming. Not only has the average temperature of the surface increased—11 of the last 12 years are the warmest on record—but the warming has been greater at higher latitudes than near the equator. It’s been greater at night than at day. The warming has caused the melting of sea ice and the thermal expansion of the ocean and an increase in sea level. And an increase in precipitation and storminess and an increase in the intensity of hurricanes. All of this is what you would expect, if the increase in greenhouse gases were the cause.
And so is this just a bad coincidence? Or is it common sense, the simplest explanation to believe that the increase in greenhouse gases is the cause, given that they do trap heat? Now, even so, you might argue that we don’t know for sure and maybe we should wait until we do know for sure. But the climate system is so complex that there is no prospect that our understanding of it, or our models of it, will be very substantially improved in 10 years or 20 years.
The sad fact is that estimates of the climate’s sensitivity, this response of the average temperature of the earth in response to an equivalent doubling of CO2, have not improved in the last 30 years. Thirty years ago, in the first National Academy report on this subject, the range was 1-1/2 to 4-1/2 degrees centigrade. It remained at that level in all of the subsequent National Academy and IPCC reports until the latest, when the range was narrowed to 1.9 to 2.4. That is despite a vast increase in research on the climate system. By the time we find out for sure whether it’s high or low, it will be too late to do anything about it. And the longer we wait to take action, the more drastic and expensive and draconian the measures will have to be.
So as you can no doubt tell, at this point I believe the risks of inaction are intolerable. Without policy action soon, greenhouse gas concentrations 50 years from now will be more than an equivalent doubling of the preindustrial concentration of carbon dioxide. And the resulting change in surface temperature was likely going to be four to eight degrees Fahrenheit. That’s basically the 1.9 to 2.4 degrees centigrade. To put this in perspective, the average temperature increase at the end of the last ice age was estimated to be about ten degrees Fahrenheit.
But it won’t stop there. As long as we continue to burn fossil fuels, the concentrations of carbon dioxide will continue to increase and temperatures will continue to rise. So these are the risks of inaction. I’m not saying that catastrophic climate change will occur if we don’t reduce greenhouse emissions. I’m only saying it’s a realistic possibility and we’re not going to be able to prove the case one way or the other anytime soon. We must make a decision to act, or not to act, under uncertainty.
Now we might decline to act if the costs were unacceptably high. But I, and many others who have studied the problem, believe that very significant reductions in carbon dioxide emissions and other greenhouse gas emissions can be achieved at a reasonable cost, equivalent to a tax of about a hundred dollars per ton of carbon. To put this in perspective, that would increase the price of oil by $12 a barrel. The current price is about $100. And it would increase the price of gasoline by 25 cents a gallon. We can afford this. We are a rich country. We’ve already seen, in recent months, price increases larger than this, and it hasn’t caused a collapse of our economy.
A tax of this magnitude would help make alternatives, like nuclear and wind, economically competitive with coal, for the production of electricity for example. Or it could lead to the sequestration of carbon from coal use. Although the total amount of money collected from a tax would be large, the effect on family incomes would be modest in most cases and could largely be offset by reducing income taxes, in effect substituting taxing income for taxing pollution.
So, quite frankly, I have a hard time understanding people who oppose such actions to reduce greenhouse gases. Either they’re so confident that the climate won’t change significantly in response to continued increase in greenhouse gas concentrations that they’re willing to dismiss completely the analysis of most climate scientists. Or they admit that climate change is a possibility, but they’re not willing to pay to avoid it. Perhaps because they understand the wealthy countries today will bear most of the cost of this, while the benefits will accrue mostly to future generations—to our grandchildren and their children, and especially in the poorest countries of the world. Though, in my way of thinking, this exhibits an indifference to the welfare of our neighbors, both current and future generations, and to creation itself. So, with that, I thank you for your attention.
Dr. Steve Fetter is Associate Director of the Joint Global Change Research Institute, and Vice Chairman of the Federation of American Scientists.
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