Worldwide, 2002 is now considered the second hottest year. Of the eight hottest years on record, six are the most recent. Nine of the ten hottest have occurred since 1990.

Kevin Trenberth, head of research for a university consortium of climate scientists says this is more evidence that the human impact on temperatures "is real; global warming is happening."

Consensus worldwide is that greenhouse gasses such as carbon dioxide from the burning of fossil fuels is a cause of the warming. Conservatives dismiss this finding, saying satellite readings indicate lower temperatures at higher elevations.