The U.N.-sponsored Intergovernmental Panel on Climate Change sent out a clear message in its third report on global warming.
"If we continue doing what we are doing now, we are in deep trouble," says Ogunlade Davidson, co-chairman of the group.
The report, which was approved by consensus of over 120 nations Friday after a weeklong meeting, calls for emissions cuts through improved energy efficiency in buildings, vehicles and appliances; transferring power sources from fossil fuels to renewable sources; protecting forests; and curbing agricultural emissions.
The panel offers a scenario for dodging the worst effects of global warming which would require greenhouse gas emissions to plateau in 15 years and drop to half of current levels by the middle of this century. The panel estimates that this plan could limit global temperature increases to 3 degrees Fahrenheit, and it would cost 3% of global gross domestic product by 2030.
European countries found the report encouraging, saying it showed that curbing global warming was feasible. But the U.S. and China produce nearly half the world's emissions, and neither appear ready to jump on board with the panel's recommendations. U.S. officials question the costs attached, and China was skeptical that results could be achieved quickly.
"The notion that all countries are going to sign on tomorrow is ridiculous," says John Reilly, an economist at the Massachusetts Institute of Technology, in an L.A. Times article.