The Sunday Times
Thu, 29 Mar 2007 09:37 CDT
Mars is being hit by rapid climate change and it is happening so fast that the red planet could lose its southern ice cap, writes Jonathan Leake.
Scientists from Nasa say that Mars has warmed by about 0.5C since the 1970s. This is similar to the warming experienced on Earth over approximately the same period.
Since there is no known life on Mars it suggests rapid changes in planetary climates could be natural phenomena.
The mechanism at work on Mars appears, however, to be different from that on Earth. One of the researchers, Lori Fenton, believes variations in radiation and temperature across the surface of the Red Planet are generating strong winds.
In a paper published in the journal Nature
, she suggests that such winds can stir up giant dust storms, trapping heat and raising the planet's temperature.
Fenton's team unearthed heat maps of the Martian surface from Nasa's Viking mission in the 1970s and compared them with maps gathered more than two decades later by Mars Global Surveyor. They found there had been widespread changes, with some areas becoming darker.
When a surface darkens it absorbs more heat, eventually radiating that heat back to warm the thin Martian atmosphere: lighter surfaces have the opposite effect. The temperature differences between the two are thought to be stirring up more winds, and dust, creating a cycle that is warming the planet.