OVER THE PAST two weeks, a House Energy and Commerce subcommittee has held a pair of truly senseless hearings on global climate change. The purpose was not to figure out how to cut carbon emissions. It wasn't even to discuss the science of global climate change in general. Instead, the purpose was to pick at a single study of global temperature patterns, the so-called "hockey stick" graph -- a trend line that purports to show a sudden and dramatic increase in global temperatures in the 1990s and therefore looks like a hockey stick. The graph is hardly central to the modern debate over climate change. Yet the subcommittee has investigated the scientists who dared produce it and hounded them for information. Now that a study of the graph by the National Academy of Sciences has largely backed up the hockey stick findings, the committee has been holding hearings to attack it some more.
A more responsible House hearing on climate change, held by the Government Reform Committee, revealed the utter frivolity of investigating the hockey stick. Even the Bush administration -- which is actively avoiding regulation of carbon emissions -- took pains to acknowledge the science of climate change. Speaking on behalf of the White House, James L. Connaughton made clear that global warming is real and that human causes are at least partly to blame.
In fact, the broad contours of climate science are a matter of considerable consensus. Increasing atmospheric concentration of greenhouse gases traps additional energy, which tends to cause warming of the Earth's surface. The actual concentration of carbon in the atmosphere has increased enormously since the advent of the Industrial Revolution. And average global temperatures have risen in recent decades, an effect that is amplified significantly in the polar regions. The major outstanding question about global warming is not whether adding large amounts of new carbon to the atmosphere will tend to increase temperatures further. It is how sensitive the climate will be to what mass of additional carbon over time -- and how bad the practical consequences of that sensitivity will be. On this point, there exists vigorous scientific debate. But it's a debate to which congressional committees are laughably ill-suited to contribute.
The reality is that nobody knows how bad global warming will be; responsible estimates vary from manageable to catastrophic. So the prudent move is to take action now as a kind of insurance policy. Yes, reducing carbon emissions substantially is a daunting prospect given American and world dependence on fossil fuels -- so daunting that it induces a kind of denial in many people. But it is a particularly ugly kind of denial that leads a congressional committee to spend this kind of energy attacking scientists, instead of confronting the problems their data suggest.