The global scientific body on climate change will report soon that only greenhouse gas emissions can explain freak weather patterns.
Simultaneous changes in sea ice, glaciers, droughts, floods, ecosystems, ocean acidification and wildlife migration are taking place.
The Intergovernmental Panel on Climate Change had previously said gases such as CO2 were "probably" to blame.
Its latest draft report will be sent to world governments next month. [...]
But the broad international expert consensus embodied in the IPCC will make it harder for the US administration to say that climate change is a problem for the future which can be solved by technological advances.
In a meeting with climate campaigners, UK Prime Minister Tony Blair said the world needed to engage the Americans, Chinese and Indians in agreement over a figure for CO2 stabilisation.
But this is unlikely to happen while US President George W Bush is in office; his representative told the December climate conference in Montreal that the US would not agree any targets for reducing CO2.
“We could have saved the Earth but we were too damned cheap.” ~Kurt Vonnegut