On 6 June 2001, a panel of top American climate scientists sent a big clue to the 800-pound gorilla of global warming politics. I believe it was the most important document on this issue since 1995. Let's see what it told the party in power.
The U.S. government has never been eager to set sweeping policies against greenhouse gas emissions. Big reductions are very expensive, and they are highly uncertain to work as advertised. The Clinton administration went along with the Kyoto Accords promising to make those reductions, but the Senate was never likely to approve the treaty—too many interests opposed it. And only in 2005 did enough nations actually ratify it to put it into action.
When George W. Bush proclaimed Kyoto a dead letter, he promised new proposals for the nations to discuss in July 2001. Hence the administration request to the National Academy of Sciences in May: "We seek the Academy's assistance in identifying the areas in the science of climate change where there are the greatest certainties and uncertainties. We would also like your views on whether there are any substantive differences between the IPCC Reports and the IPCC summaries."
The IPCC, the Intergovernmental Panel on Climate Change, is the United Nations agency that reports on the state of research roughly every five years. The "IPCC summaries" are the widely reported Summaries for Policy Makers, shorter documents that are issued by a large committee of scientists plus policymakers. The 1995 IPCC review was a prime driver behind the Kyoto Accords, but a lively debate followed, which was not settled by the 2001 report.
The Whit House's two-sentence request is an echo of that debate. The first sentence, on certainties and uncertainties, asks a question best suited for science. It is desirable to negotiate matters that are relatively certain, while directing resources toward those that are less certain. The public does not widely appreciate this problem, but sound policy depends on it. Uncertainty is not necessarily a dodge to avoid taking action but a genuine obstacle. The second sentence, in essence, asks whether the IPCC process is politicized. That has always been the fear of Kyoto opponents.
The Academy put together a distinguished panel from the National Research Council. In less than four weeks it returned a lucid paper that is a better read than the IPCC report. Let me summarize how the NRC report answered the White House's two questions.
Where are the greatest certainties and uncertainties in the science of climate change?
What is certain is that greenhouse gases are still rising due to human causes (though not at an accelerating rate as the IPCC assumed), that the world's global average surface temperature is rising (especially recently), and that the world's global average stratospheric temperature is falling (during the short period we've observed it). It is certain that any changes in carbon dioxide levels will persist for centuries, while other greenhouse gases like methane and ozone can be affected much faster. It is certain that climate science has enormous room for improvement and that support for research is unreliable.
The uncertainties far outnumber the certainties. The magnitudes are poorly known for many basic factors, including the production and destruction of greenhouse gases and aerosols, the effects and feedbacks of clouds, the sensitivities of the climate system to changes, the natural variations in global temperature, the history of world climate, the behavior of water vapor, the history and effects of human land uses, and the role of the ocean in absorbing energy and greenhouse gases. We also know very little about how global climate changes translate into specific effects at the regional level, where people will have to respond in concrete ways.
What are the substantive differences between the IPCC Reports and the IPCC summaries?
The IPCC report is scientifically credible and much like what a group of American scientists would produce. But the Summary for Policy Makers tends to speak of conclusions being "likely" or "unlikely" without explaining the basis for uncertainty; with that omission, the Summary may make it seem that the science is settled when that is not the case. (The 2007 report did much better on this score.)
The NRC panel went on to discuss an underlying question: whether the work of the IPCC will continue to be fair and representative. Participating in the IPCC process is important, but also a big time sink. Many scientists decline to join it, and the panel warns that "this could create a form of self-selection for the participants. In such a case, the community of world climate scientists may develop cadres with particularly strong feeling about the outcome." Moreover, the role of government officials in preparing the Summary invites political influences when discussing things like treaties and emission controls. In sum, the panel says, "there is a risk that future IPCC efforts will not be viewed as independent processes."
Finally, the panel noted some specific issues for the U.S. scientific community. Paramount is the need for a long-term system of collecting observations instead of the current patchwork of programs. The paper calls for more research aimed at helping society use scientific knowledge to respond to climate change.
In its last paragraph, the NRC report takes direct aim at the administration. It castigates the umbrella climate agency, the U.S. Global Change Research Program (USGCRP), as "hampered organizationally." In summary, it says, "the ability of the United States to assess future climate change is severely limited by the lack of a climate observing system, by inadequate computational resources, and by the general inability of government to focus resources on climate problems."
Seeing that American science research is innovative, effective, and efficient is a public-policy job, not a partisan issue. Not just the Bush administration, but Congress too needs to do its part. The lessons in this report are for all sides in the climate debate, and for every citizen who understands science.
