The National Academy of Sciences and 10 similar organizations from some of the world's most powerful nations released a statement Tuesday calling for a stronger international response to global warming, arguing there is now more than enough evidence of a changing climate to justify taking immediate action.
The unprecedented joint statement, politically timed to coincide with British Prime Minister Tony Blair's visit with President Bush in Washington, called on developed nations to "acknowledge that the threat of climate change is clear and increasing."
It also called on countries to begin setting stricter targets to reduce heat-trapping greenhouse gases to prevent the worst consequences of global warming from taking place.
The statement was signed by National Academy of Sciences President Bruce Alberts as well as the heads of science organizations from Brazil, Britain, Canada, China, France, Germany, India, Italy, Japan and Russia. That includes science academies from the Group of 8 industrial nations, as well as from the three largest emitters of greenhouse gases in the developing world.
"There will always be uncertainty in understanding a system as complex as the world's climate," the joint statement began.
"However, there is now strong evidence that significant global warming is occurring."
The evidence includes direct measurements of rising air and ocean temperatures, retreating glaciers and changes to biological systems, the scientists wrote. They added that "it is likely that most of the warming in recent decades can be attributed to human activities," such as the release of carbon dioxide and other greenhouse gases from the burning of coal and other fossil fuels.
In releasing the statement, the president of the British Royal Society, Lord Robert May, sharply criticized the Bush administration's stance on climate change, which is focused on furthering technologies to cut greenhouse gas emissions and only asks that businesses make voluntary reductions.
The U.S., the world's largest emitter of carbon dioxide, was the only major developed nation other than Australia not to sign the Kyoto Protocol, a pact to reduce greenhouse gas emissions to roughly 5% below 1990 levels by 2012. Blair has vowed to make climate change a central issue at next month's G-8 summit in Gleneagles, Scotland. But the Bush administration appears firmly entrenched in its position that mandating reductions in greenhouse gases would hurt the U.S. economy.
