Dim Martian Surface May Fuel Global Warming On the Red Planet

Darkness and heat feed on each other in new simulations that predict a 20-year warming trend on the Red Planet

A darkening of the Martian surface may have slowly warmed the planet over the past 20 years. Based on a model of the Red Planet's climate, researchers report that the brightness or darkness of its sands have a strong effect on its atmospheric temperature. They found that the heat absorbed by dark rock kicks up winds that blow away shiny dust, leaving behind even darker rock. But the predicted warming is hard to confirm, researchers say, and could shift with the sands at any time.

Snapshots over the past three decades have shown vast regions of the Red Planet's surface have brightened or darkened by 10 percent or more, reflecting between 10 and 30 percent of incoming sunlight in total. To determine if albedo or reflectivity changes affect the climate, researchers compared Viking orbiter photos from 1976 to 1978, which mapped the planet's bright and dark spots, to those from 1999 to 2000, when the Mars Global Surveyor discovered a darker Mars.