Reposted from:
http://www.nytimes.com/2007/11/20/opinion/20tue1.html

The world's scientists have done their job. Now it's time for world leaders, starting with President Bush, to do theirs. That is the urgent message at the core of the latest — and the most powerful — report from the Intergovernmental Panel on Climate Change, a group of 2,500 scientists who collectively constitute the world's most authoritative voice on global warming.

Released in Spain over the weekend, the report leaves no doubt that man-made emissions from the burning of fossil fuels (and, to a lesser extent, deforestation) have been responsible for the steady rise in atmospheric temperatures.

If these emissions are not brought under control, the report predicts, the consequences could be disastrous: further melting at the poles, sea levels rising high enough to submerge island nations, the elimination of one-quarter or more of the world's species, widespread famine in places like Africa, more violent hurricanes.

And it warns that time is running out. To avoid the worst of these disasters, it says, the world must stabilize emissions of greenhouse gases by 2015, begin to reduce them shortly thereafter and largely free itself of carbon-emitting technologies by midcentury.

As Rajendra Pachauri, a scientist and economist who leads the I.P.C.C., noted: "What we do in the next two or three years will define our future."

Deep in all this gloom is a considerable ray of hope: significant progress toward stabilizing and reducing emissions can be achieved using known technologies. This a hugely important message for policy makers and for those who say there's no point in spending money on the problem because the game is already lost. The world does not have to rely on pie-in-the-sky technologies, the report insists. What it really needs is a policy structure to encourage major investments in cleaner technologies that are already at hand or within reach.

The report's urgent warnings and its message of hope could not be more timely. Nations will gather in Bali next month to begin framing a successor to the Kyoto Protocol on climate change, which expires in 2012. Under normal circumstances, Bali would be the beginning of a long, contentious process; Kyoto, negotiated in 1997, did not take effect for seven years. What the I.P.C.C. is saying is that the world cannot afford to wait for another grand agreement, and certainly not for another seven years. It needs action now.

Every member of Congress should read this report. The Senate has begun hearings on legislation that would put a mandatory cap on carbon emissions. The bill is not perfect and, to some critics, not strong enough. But it is a worthy start and would move the United States toward the cleaner fuels and carbon-free technologies essential to the task of changing the way the world produces and uses energy.

Mr. Bush should also read it and order extra copies for members of his staff. After years of denial, the president now concedes that a problem exists. But he still insists on voluntary remedies and still worries about the costs to the American economy of anything more ambitious. If there is one message Mr. Bush and other world leaders must take away from the scientists, it is that the price of more delay will be far greater.