Global Warming The debate on global warming has shifted. Worldwide, tailpipes and smokestacks spew 25 billion tons of carbon dioxide every year, and there's no longer doubt that this gas is heating the Earth. The new questions center around how much will our climate change, and how fast. NPR examines the issue.

Special Series
Global Warming
The new debate on global warming is how much will our climate change, and how fast.Wednesday
Audio will be available later today.