John on April 4, 2007 at 11:59 pm
I know this is supposedly a long ago dismissed point. But there’s new information suggesting it shouldn’t have been dismissed so quickly:
Glistening Martian dust lying on the ground reflects the Sun’s light — and its heat — back into space, a phenomenon called albedo.
But when this reddish dust is churned up by violent winds, the storm-ravaged surface loses its reflective qualities and more of the Sun’s heat is absorbed into the atmosphere, causing temperatures to rise.
The study, published on Thursday by the British journal Nature, shows for the first time that these variations not only result from the storms but help cause them too.
It also suggests that short-term climate change is currently occurring on Mars and at a much faster rate than on Earth.
On Mars, there have been an unusual number of massive, planet-darkening storms over the last 30 years, and computer models indicate that surface air temperatures on the Red Planet increased by 0.65 C (1.17 F) during from the 1970s to the 1990s.
Residual ice on the Martian south pole, they note, has steadily retreated over the last four years.
By comparison, the average temperature of Earth increased by 0.75 C (1.33 F) over the last century.
So Mars in warming rapidly because of global changes in reflectivity caused by an increase in storms. But no one knows what caused the increasing storms. Well, I think we know what didn’t cause them…us.
Category: Science & Tech |