60秒科学:Earth's Fried Far-Future Postponed（在线收听）

Earth's Fried Far-Future Postponed
A study in the Proceedings of the National Academy of Sciences adds at least a billion years to the already far-future estimate of when the sun will make Earth too hot to handle. Karen Hopkin reports.

[The following is an exact transcript of this podcast.]

About a billion years from now, some scientists say, the sun will be too bright for comfort, and our formerly hospitable planet will no longer be able to support life. If visions of this impending heat death disturb you, researchers from the California Institute of Technology have some good news. Their calculations add at least another billion years to Earth's expiration date, results published in the Proceedings of the National Academy of Sciences.

As our sun matures it grows brighter and hotter. And over the past three or four billion years, the Earth’s been coping with the extra rays by getting rid of some of the CO2 in the atmosphere. Thinning out the CO2 that blankets the earth helps to keep things cool. But that can't go on forever because we'd be left with no blanket at all.

Now the Caltech scientists say that the planet may be able to compensate by removing nitrogen from the atmosphere. That'll decrease atmospheric pressure, which will then loosen the weave of the CO2 blanket and allow more heat to escape. So stop and smell the roses. We may have an additional billion years to figure out this extreme case of global warming.

—Karen Hopkin