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Mars Warming Sure to Heat Up Political Debate
Republican climate change skeptics in Congress are bound to delight in the news that Mars is experiencing its own warming trend. Yes, by the bloodlust of Ares, our ruddy celestial neighbor heated up by 1 degree Fahrenheit from the 1970s to the 1990s, NASA scientists reported today. The scientists published their results in Nature this week and attributed the warming to dust storms that expose dark rock that absorbs more heat from the sun.
Because hotter temperatures create more dust storms, Mars will likely continue to warm up, which is dandy for Republicans like Rep. Dana Rohrabacher (R-California). In a hearing last week, Rohrabacher lamented the "arrogant" and "anti-scientific" dismissal of global warming research funded by oil and gas companies. Rohrabacher then proceeded to dismiss the overwhelming majority of scientists who believe global warming is real and caused by humans. He managed to smuggle in a Mars warming reference to back up his point.
And he's not alone. Here's Rep. Michael Burgess (R-Texas) in a hearing last month: "Apparently, Mars, too, is afflicted with global warming. Are humans responsible for that too?"
Burgess said this in as nice a way as possible, but more often than not, the Mars warming reference is dropped with a sneer. It has become one of the cynical weapons Republican skeptics have deployed recently to stall action in Congress on global warming. Problem is, the skeptics have always claimed that Mars is warming up because of solar activity, which, quite naturally, could be used to explain earth's warming and, quite naturally, could be used as a justification for inaction.
But the NASA researchers determined that Mars' warming has little to do with solar flares or sun spots and everything to do with dust that acts just like greenhouse gases in our atmosphere. Let the spinning begin.
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Republican climate change skeptics in Congress are bound to delight in the news that Mars is experiencing its own warming trend. Yes, by the bloodlust of Ares, our ruddy celestial neighbor heated up by 1 degree Fahrenheit from the 1970s to the 1990s, NASA scientists reported today. The scientists published their results in Nature this week and attributed the warming to dust storms that expose dark rock that absorbs more heat from the sun.
Because hotter temperatures create more dust storms, Mars will likely continue to warm up, which is dandy for Republicans like Rep. Dana Rohrabacher (R-California). In a hearing last week, Rohrabacher lamented the "arrogant" and "anti-scientific" dismissal of global warming research funded by oil and gas companies. Rohrabacher then proceeded to dismiss the overwhelming majority of scientists who believe global warming is real and caused by humans. He managed to smuggle in a Mars warming reference to back up his point.
And he's not alone. Here's Rep. Michael Burgess (R-Texas) in a hearing last month: "Apparently, Mars, too, is afflicted with global warming. Are humans responsible for that too?"
Burgess said this in as nice a way as possible, but more often than not, the Mars warming reference is dropped with a sneer. It has become one of the cynical weapons Republican skeptics have deployed recently to stall action in Congress on global warming. Problem is, the skeptics have always claimed that Mars is warming up because of solar activity, which, quite naturally, could be used to explain earth's warming and, quite naturally, could be used as a justification for inaction.
But the NASA researchers determined that Mars' warming has little to do with solar flares or sun spots and everything to do with dust that acts just like greenhouse gases in our atmosphere. Let the spinning begin.
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Dust blamed for warming on Mars
NewScientist.com news service
David L Chandler
Scientists have been puzzling over the cause of dramatic global warming on Mars, which has made parts of the south polar ice cap disappear in recent years. The answer, it seems, is blowing in the wind: the planet's famous reddish dust.
Using global circulation models similar to those used to analyse Earth's changing climate, a team led by Lori Fenton of NASA's Ames Research Center in California, US, found that Mars seems to have warmed by about 0.65° Celsius in the three decades since the Viking mission first provided detailed mapping of the whole planet.
That warming can be explained entirely by the scouring away of light-coloured dust from darker areas of the surface, causing an increase in the absorption of solar radiation.
This effect is greatly amplified by positive feedback: The warmer ground causes stronger winds, which in turn scour away more of the light dust and lead to greater warming.
Team member Paul Geissler, a planetary geologist at the US Geological Survey in Flagstaff, Arizona, says the mechanism can account for the rapid warming that has been seen in the disappearing polar caps, which are turning directly from solid to vapour at a rapid rate (watch an animation showing Mars's south polar cap change from 1999 to 2005).
Global dust storm
The overall distribution of dark and light areas on Mars has clearly changed since Viking (watch an animation of the surface reflectivity changes over the entire planet). The new modelling shows that the heating produced by those changes is "the same order of magnitude" as that required for the rapid removal of the polar ice, Geissler says.
At some point, the model predicts the winds will build up so much they will trigger a global dust storm, redistributing the light dust over most of the surface and starting the process over again.
While the dust redistribution may be unique to Mars, Earth may have analogous feedback processes that can amplify changes in surface reflectivity – in this case, mostly based on changes in sea ice and snow cover.
But although some scientists argue that the global warming on Mars shows there must be some external cause to Earth's warming – such as a change in solar output rather than human-caused increases in greenhouse gases – Geissler says the new research undercuts that argument. "What our work shows is that the warming on Mars that we know has been going on for some time has a local cause [on Mars]," he told New Scientist.
The new work could have a significant impact on understanding past changes in the Martian climate. "This is the first attempt to quantify the impact of these surface changes," Geissler said. From now on, "when we study Mars' climate, we need to keep track of the surface [reflectivity] and its interaction with climate."
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It looks like the republicans will have to find a new defense. They are getting desperate but the truth will prevail.
NewScientist.com news service
David L Chandler
Scientists have been puzzling over the cause of dramatic global warming on Mars, which has made parts of the south polar ice cap disappear in recent years. The answer, it seems, is blowing in the wind: the planet's famous reddish dust.
Using global circulation models similar to those used to analyse Earth's changing climate, a team led by Lori Fenton of NASA's Ames Research Center in California, US, found that Mars seems to have warmed by about 0.65° Celsius in the three decades since the Viking mission first provided detailed mapping of the whole planet.
That warming can be explained entirely by the scouring away of light-coloured dust from darker areas of the surface, causing an increase in the absorption of solar radiation.
This effect is greatly amplified by positive feedback: The warmer ground causes stronger winds, which in turn scour away more of the light dust and lead to greater warming.
Team member Paul Geissler, a planetary geologist at the US Geological Survey in Flagstaff, Arizona, says the mechanism can account for the rapid warming that has been seen in the disappearing polar caps, which are turning directly from solid to vapour at a rapid rate (watch an animation showing Mars's south polar cap change from 1999 to 2005).
Global dust storm
The overall distribution of dark and light areas on Mars has clearly changed since Viking (watch an animation of the surface reflectivity changes over the entire planet). The new modelling shows that the heating produced by those changes is "the same order of magnitude" as that required for the rapid removal of the polar ice, Geissler says.
At some point, the model predicts the winds will build up so much they will trigger a global dust storm, redistributing the light dust over most of the surface and starting the process over again.
While the dust redistribution may be unique to Mars, Earth may have analogous feedback processes that can amplify changes in surface reflectivity – in this case, mostly based on changes in sea ice and snow cover.
But although some scientists argue that the global warming on Mars shows there must be some external cause to Earth's warming – such as a change in solar output rather than human-caused increases in greenhouse gases – Geissler says the new research undercuts that argument. "What our work shows is that the warming on Mars that we know has been going on for some time has a local cause [on Mars]," he told New Scientist.
The new work could have a significant impact on understanding past changes in the Martian climate. "This is the first attempt to quantify the impact of these surface changes," Geissler said. From now on, "when we study Mars' climate, we need to keep track of the surface [reflectivity] and its interaction with climate."
Source