Sceptics have said a slowing of the pace of warming this century after fast gains in the 1980s and 1990s, is a sign that global warming may not be as urgent a problem as previously believed, despite a major UN report on climate change due to be published today.
Some countries stressed that it was also "virtually certain", or at least 99 percent probable, that natural variations in the climate were not the sole cause.
The report will face extra scrutiny after the IPCC made errors in its 2007 report, including an exaggeration of the melt rate of Himalayan glaciers. An outside review of the IPCC found that the mistake did not affect its main conclusions.
Presenting the most vivid evidence to date, the UN's IPCC report has warned that humans are responsible for changes to the earth's climate.
The UN IPPC report into climate change, due out tomorrow, will say scientists agree the world is getting warmer, and humans are to blame.