The administration of US President George W. Bush has long rejected the role of human activity on the phenomenon, even as experts estimate that one quarter of the heat-trapping pollutants in the atmosphere come from US sources.


However, a steady stream of pressure from international experts, public opinion, the new Democratic majority in Congress and even the Supreme Court has chipped away at that stance.

In early April, the United States acknowledged the alarming diagnosis of global warming and its potential disastrous consequences after the release of a report by the Intergovernmental Panel on Climate Change (IPCC), the United Nations's top authority on global warming which meets this week in Bangkok to discuss measures to take in response.