In a move that will surely force action on reining in CO2 emissions, the EPA has declared CO2 and five other heat-trapping gases to be pollutants.

Pollutants represent a threat to human health and welfare, and acknowledging that cliamte change-contributing gases fall into that category brings them within the EPA's regulatory remit.

This development means that the US Congress will come under intense pressure to agree on climate change legislation, and probably in time for the UN climate hange conference in Copenhagen in December.