Wednesday, November 28, 2007
It turns out we have a model of a planet experiencing a "runaway greenhouse effect" right next door. The latest orbital probe of Venus has led European Space Agency scientists to speculate that our neighbor in the solar system was once partially covered with water.
"Probably because Venus was closer to the sun, the atmosphere was a little bit warmer and you got more water very high up," he said.
As water vapour is a greenhouse gas, this further trapped solar heat, causing the planet to heat up even more.
It was a "positive feedback" - a vicious circle of self-reinforcing warming - that eventually caused the planet to become bone dry.
Talk about an uninviting environment, by the way: 457 degrees farenheit on the surface, with sulfuric acid-laced clouds. Ouch.
Update: And speaking of bone dry, this article on the coming water scarcity is pretty thought-provoking.