NASA's James Hansen frequently clashes with global warming 'deniers,' as well as the Bush administration.
People with no formal training are helping scientists track and record birds, fish, stars, and plants in their neighborhoods online.
Too few people are changing their lifestyles, environmentalists say, and too few politicians are acting.
Should the world put less focus on emissions caps and more on spurring clean technologies?
Tiny particles heat up the atmosphere faster than scientist once believed. The good news is this dust can be cleaned up fairly quickly.
Supreme Court has ruled that EPA can regulate greenhouse-gas emissions from cars, but administration says deliberation needed.
Twenty-five cities around the world will participate in the World Wildlife Fund campaign.
Even when experts look at the same data, they can come to vastly different conclusions.
By December 2009, binding greenhouse-gas emissions policies will be set for developing countries.
This global threat requires a war-room mentality.
A thousand tons of water produces just one ton of grain.
Rivers fed by melting glaciers across Latin America may soon dry up, forcing changes on the people who depend upon them.
The environmental disaster springs largely from its emulation of the American way of life â€“ so let's set a better example.
EU foreign affairs chief Javier Solana warns in a new report that detrimental climatic changes could drive millions of migrants to Europe from developing countries.
EU report adds urgency to old warnings, NATO to take up discussion next.
But their unofficial call to action has kindled skepticism within the conservative denomination.
It takes a lot of energy to make it, and the world is using billions of tons of it. Makers are finding better ways to do it.
'Carbon rationing action groups' – where members swap tips and set targets – are cropping up across the country.
A skirmish last week over setup costs only foreshadows the battles ahead for the landmark bill that would slash emissions by 2020.
Natural variations in weather can vary more than climate change signals, experts say.