The recent escalation of attacks on the science of climate change and on scientists working in this field by the small number of climate deniers and their political supporters has drawn a sharply worded response from 255 members of the U.S. National Academy of Sciences, including at least 11 Nobel laureates. In an essay published in the May 7th issue of the journal Science as the Lead Letter, the scientists say:
"We are deeply disturbed by the recent escalation of political assaults on scientists in general and on climate scientists in particular."
The essay continues:
"There is compelling, comprehensive, and consistent objective evidence that humans are changing the climate in ways that threaten our societies and the ecosystems on which we depend."
In recent months, a small minority of vocal climate deniers have been emboldened by minor errors identified in some of the international scientific assessments of climate change and by the publication of private email exchanges from some in the climate community. A recent independent commission in the UK, chaired by Lord Ron Oxburgh to review this debate, concluded that, "We found absolutely no evidence of impropriety whatsoever." The Science essay explicitly and strongly addresses these issues, saying:
" there is nothing remotely identified in the recent events that changes the fundamental conclusions about climate change:
- The planet is warming due to increased concentrations of heat-trapping gases in our atmosphere. A snowy winter in Washington does not alter this fact.
- Most of the increase in the concentration of these gases over the last century is due to human activities, especially the burning of fossil fuels and deforestation.
- Natural causes always play a role in changing Earth's climate, but are now being overwhelmed by human-induced changes.
- Warming the planet will cause many other climatic patterns to change at speeds unprecedented in modern times, including increasing rates of sea-level rise and alterations in the hydrologic cycle. Rising concentrations of carbon dioxide are making the oceans more acidic.
- The combination of these complex climate changes threatens coastal communities and cities, our food and water supplies, marine and freshwater ecosystems, forests, high mountain environments, and far more."
The essay also includes a sharply worded rebuke to politicians who have recently threatened climate scientists whose scientific conclusions disagree with their political inclinations.
"We also call for an end to McCarthy-like threats of criminal prosecution against our colleagues based on innuendo and guilt by association, the harassment of scientists by politicians seeking distractions to avoid taking action, and the outright lies being spread about them."
It is hard to get 255 members of the U.S. National Academy of Sciences to agree on pretty much anything, making the import of this letter even more substantial. Moreover, only a small fraction of National Academy members were asked to sign (the signatories are all members of the U.S. National Academy of Sciences but were not speaking on its behalf). Because of a desire to produce a statement quickly, the coordinators of the letter focused on those sections of the NAS most familiar with climate science and the ongoing debate. But the NAS (and Academies of Sciences and other professional scientific societies from dozens of other nations) has previously published a long set of assessments and reviews of the science of climate change, which support the conclusions laid out in the Science essay.
And in the concluding paragraph of the essay, this group of leading scientists argues for taking action to deal with the risks of climate change:
"Society has two choices: we can ignore the science and hide our heads in the sand and hope we are lucky, or we can act in the public interest to reduce the threat of global climate change quickly and substantively."
In the end, we have only three choices: we can act to mitigate the risks of climate change by reducing greenhouse gas emissions, we can expand efforts to adapt to a changing climate, or we can suffer the consequences of doing nothing. The only real question is, what is the balance among these three options.
Are the climate deniers going to go away? No. Nothing will convince them, since science hasn't. There are still people -- a lot of people -- who do not believe in evolution, or plate tectonics, or the Big Bang theory. But the longer that policymakers hesitate to act, the more the balance will shift to suffering. I believe that history will prove those delaying action to be dangerously wrong, at a time when it is urgent that society be courageously right.
Peter H. Gleick is one of the 255 signers of the Lead Letter in the May 7th issue of the journal Science.