CHICAGO Earth's dusty neighbor Mars is
grappling with its own form of climate change as fluctuating
solar radiation is kicking up dust and winds that may be
melting the planet's southern polar ice cap, scientists said on
Researchers have been watching the changing face of Mars
for years, studying slight differences in the brightness and
darkness of its surface.
These changes in brightness have been generally attributed
to the presence of dust, but until now their effect on wind
circulation and climate has not been clear.
NASA scientist Lori Fenton and colleagues, reporting this
week in the journal Nature, now believe variations in radiation
from the surface of Mars are fueling strong winds that stir up
giant dust storms, trapping heat and raising the planet's
By studying changes in light reflected from the surface of
Mars -- a measure known as an object's albedo -- they predict
the red planet has warmed by around 1 degree Fahrenheit (0.65
degree Celsius) from the 1970s to the 1990s, which may in part
have caused the recent retreat of the southern polar ice cap.
On earth, carbon dioxide traps infrared radiation which can
affect global climate. This a phenomenon is known as the
greenhouse effect. Fossil fuel emissions add to the problem.
On Mars, it's the red-tinged dust.
Fenton's team compared thermal maps gathered from NASA's
Viking mission in the 1970s with maps gathered more than two
decades later by the Global Surveyor.
They saw that large swaths of the surface have darkened or
brightened over the past three decades.
These albedo changes strengthened winds, picking up and
circulating dust, creating a vicious cycle that is warming the
"Our results suggests that documented albedo changes affect
recent climate change and large-scale weather patterns on
Mars," Fenton's team wrote.
They believe changes in albedo should be an important part
of future studies on atmosphere and climate change.