n expert panel at the National Academy of Sciences is calling for an early warning  system to alert us to abrupt and potentially catastrophic events triggered by climate change.

The committee says science can anticipate some major changes to the Earth that could affect everything from agriculture to sea level. But we aren't doing enough to look for those changes and anticipate their impacts.

And this is not a matter for some distant future. The Earth is already experiencing both gradual and abrupt climate change. The air is warming up slowly, and we're also seeing rapid changes such as the melting Arctic ice cap.