Climate science vs. Washington politics

Speaker John Boehner has made some encouraging statements since last week’s election, pointing toward productive policy-making. This was not one of them: “I don’t think there’s any doubt that we’ve had climate change over the last 100 years,” he told USA Today. “What has initiated it, though, has sparked a debate that’s gone on now for the last 10 years.”

The Ohio Republican continued: “I don’t think we’re any closer to the answer than we were 10 years ago.”

President Barack Obama recently sounded some positive notes on climate change, perhaps the most neglected big issue of the 2012 campaign. His comments rekindled hopes of environmentalists that his second term will see more aggressive policymaking to combat global warming than did his first. Boehner’s words, which appear to mischaracterize the scientific debate on global warming, indicate that blinkered Republican opposition to doing much of anything about the problem may persist.

Climate science is complicated, but the basic physical principles on which the scientific consensus is based are not. Gases such as carbon dioxide trap the energy that pours down on the Earth from the sun, making the Earth habitable. Since the middle of the 20th century, scientists have studied the warming effects of adding large amounts of additional heat-trapping gases to the atmosphere, and they have made great progress since then in describing how and why the world is warming, and how that trend is likely to play out years and decades from now.

Scientists use real-world observations to describe the climate’s past, recent and distant. Then they build complex models that reflect those and other observations and run them on supercomputers. After decades of this, nearly every expert agrees that global warming is a problem and that a chief cause is the oil, gas and coal burned by humans. The biggest question now is not whether human-produced greenhouse emissions have an effect but how significant that effect will be.

In Boehner’s “last 10 years” alone, the models and the quality of the information that feeds into them have gotten progressively better. Just last week, the journal Science published a study from two climate researchers at the National Center for Atmospheric Research that addresses the behavior of clouds in different climate models, one of the primary sources of continuing uncertainty about how sensitive the climate will be to increased levels of carbon dioxide. Using satellite measurements of relative humidity, they determined that the models that predict relatively modest warming did not reflect the satellite record as well as those predicting much more alarming outcomes. In other words, the more pessimistic models are likely to be more accurate.

Predictions about the future climate must be tempered by an appreciation of the uncertainties inherent to describing extremely complicated earth systems. But the risks of global warming that decades of science describe are clearly great enough to warrant action.

Boehner’s office told us that the speaker was talking about the stagnation of the policy debate over the past 10 years, not the state of the science. If that’s the case, then he should be willing to stand up for the climate researchers and push Washington’s policy.