As seen at the Washington Post:
The world’s leading climate scientists said global warming has begun, is “very likely” caused by man, and will be unstoppable for centuries, according to a report obtained Friday by The Associated Press.[...]
“The observed widespread warming of the atmosphere and ocean, together with ice-mass loss, support the conclusion that it is extremely unlikely that global climate change of the past 50 years can be explained without external forcing, and very likely that is not due to known natural causes alone,” said the report by the Intergovernmental Panel on Climate Change _ a group of hundreds of scientists and representatives of 113 governments.[...]
While critics call the panel overly alarmist, it is by nature relatively cautious because it relies on hundreds of scientists, including skeptics.