spacetoday.net: Changing albedo may explain Martian global warming

Posted: Mon, Apr 9, 2007, 2:44 PM ET (1844 GMT)
Mars seen by Hubble August 2003 (STScI)

An increase in temperatures measured in the atmosphere of Mars may be explained by changes in the albedo, or reflectivity, of the planet's surface. In a paper published in the latest issue of the journal Nature, researchers noticed a correlation between increasing atmospheric temperatures measured since the 1970s and a decrease in the planet's albedo. The albedo decrease, apparently caused as more areas of darker bedrock have been exposed, causes the planet to absorb more sunlight and warm the atmosphere. The increased temperatures can cause an increase in the number and intensity of dust devils, which helps scour dust from the surface, revealing more areas of darker bedrock and creating a positive feedback effect. While this may explain short-term changes in the Martian climate, researchers cautioned that other factors may influence Martian climate over longer time spans.