Consensus Reached on Climate Change Causes

Article excerpt

While the politics of global warming inspire division and argument among nations, the world's scientists have reached a consensus on what causes climate change. Hundreds of top researchers from more than 80 countries agreed last week that carbon dioxide and other greenhouse gas pollutants represent the most important forces currently altering the climate, drowning out other effects that can cool the globe.

To produce the authoritative document, the Intergovernmental Panel on Climate Change (IPCC) enlisted more than 140 scientists to write the report and then sent the work to 230 reviewers. "We involved virtually all the scientists in the world who have done serious research in this area," British climate researcher John Houghton, who cochaired the science working group that produced the assessment, told SCIENCE NEWS.

The IPCC report notes that scientists still face many uncertainties regarding climate change. These outstanding questions, however, have not contradicted the basic conclusions that the group reached in its first major report in 1990. At the time, the IPCC stated with confidence that greenhouse gas emissions would warm the climate. It predicted that without any limits on these emissions, the climate would warm by roughly 1[degrees]C by 2025 and 3[degrees]C by the year 2100.

"It is interesting that in this very uncertain area, over a period of 5 years, the essential story remains the same. There's been no evidence that's come to light to destroy those basic findings," Houghton says.

Since the initial report, some researchers have explored whether changes in solar radiation or emissions of light-blocking sulfur pollution could offset warming caused by greenhouse gases. …