Mars hots up - Dust storms and dark rocks are making the red planet hotter.

news@nature.com ^ | 4 April 2007 | Katharine Sanderson

[neverdem]

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Published online: 4 April 2007; | doi:10.1038/news070402-5

Mars hots up

Dust storms and dark rocks are making the red planet hotter.

Katharine Sanderson

Hot stuff: darker areas heat up in the sunshine. NASA

Mars is getting hotter. Measurements of the brightness of the planet's surface show that the thermometer has ratcheted up some 0.65 °C over a few decades.

Lori Fenton at the Carl Sagan Center, Mountain View, California, and colleagues looked at maps of Mars's 'albedo', a measure of how much light reflects off a surface. By comparing a map from 1976-78 with one from 1999-2000, they found "some pretty dramatic changes", says Fenton. In particular, the southern highlands region of Mars had darkened significantly.

The darkening is thanks to the clearance of light-coloured dust that covers the planet's darker bedrock, they propose. When the Sun's light hits dark rock it warms the surface, and the heat is kept in by the atmosphere. This warming kicks up winds, which swirl any dust around and can even make dust devils. This sweeps the light-coloured dust into pockets, revealing more bedrock and causing further heating.

"The two processes that lift dust are being enhanced by the darkening of the surface, and those are the processes that darken the surface in the first place," says Fenton.

Fenton then used a model of the planet's climate to infer the temperature change caused by this darkening. These models are very similar to those used to predict the weather on Earth, but with fewer parameters: Mars has no oceans or vegetation, and the effects of clouds are nowhere near as important as they are on Earth.

Here today, gone tomorrow

Using these results, one might come to the conclusion that in 500 or so years the martian polar ice-caps will be completely gone, notes Phil Christensen, a planetary scientist at Arizona State University, Tempe. But, he says: "I don't think that's likely. They're looking at a piece of the cycle, other processes could turn this around to a place where the ice-caps start growing again."

A major dust storm that engulfs the entire planet, for example, could redistribute dust more evenly around the planet and instigate cooling. "Dust storms are like a reset mechanism," says Fenton. Such storms were seen on the planet in the 1970s.

Fenton's work shows nicely how conditions on Mars have changed on decadal timescales, says Christensen. But the results shouldn't be taken further than that: "You can't take 10 years of data and extrapolate out to 1,000 years," he says.

Big change

David Paige, a planetary scientist at the University of California, Los Angeles, says that Mars's albedo will surely affect the climate. But he is sceptical about the magnitude of the temperature change calculated by Fenton: "That's a big change," he says of 0.65 °C.

Paige notes that the data for the study come from two different sources: the albedo map from the 1970s was produced by the Infrared Thermal Mapper onboard the Viking mission, and the more recent map comes from the Thermal Emission Spectrometer aboard Mars Global Surveyor. Perhaps differences between these two instruments might make it inappropriate to compare their data directly, he says.

Paige is currently waiting to analyse the latest albedo data from the Mars Climate Sounder on Mars Reconnaissance Orbiter.

The warming on Mars is likely to be seized by climate-change sceptics here on Earth - if Mars is hotting up even without any cars or pollution, then perhaps the Sun or some other natural, Solar-System-wide factor is to blame. But to infer that would be "crazy" says Christensen (see 'Hot times in the Solar System').

"The more we learn about Mars, the more intuition it gives us about Earth, but the systems are fundamentally different," he says.

Visit our newsblog to read and post comments about this story.

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References

1. Fenton I., Geissler P. E. & Haberle R. M.. Nature, 446 . 646 - 649 (2007). | Article |

[JennysCool]

Can’t be the sun doing it. That would indicate a natural warming cycle and development of earth’s “global warming” industry would never get off the ground!

[Slings and Arrows]

In a related story, Al Gore has offered to sell the Martians carbon credits.

[Ieatfrijoles]

The Martians are cooking the books.

[LukeL]

Wow, if you factor in the distance Mars is from the Sun and its atmosphere compared to Earth the warming numbers indicate a natural event with the sun.

Either that or those rovers we sent to Mars are releasing tons of greenhouse gases and nuclear bric-a-brac

[Hugin]

It’s Bush’s fault.

[spokeshave]

"You can't take 10 years of data and extrapolate out to 1,000 years," he says."

And the converse.....

Hey Al ....you can't take 10,000 years of fake made up data and extrapolate out 100 years.

[CometBaby]

aha! Just as we all suspected .. Global Warming on Mars !!!

This proves there must be life on mars because only evil humans could cause all that hot stuff!! hehe

[neverdem]

CC Ping

[Names Ash Housewares]

“On Mars, the warming seems to be down to dust blowing around and uncovering big patches of black basaltic rock that heat up in the day (see ‘Mars hots up’). No change in sunshine required.”

That is from the link in the story.

Wind is caused by unequal heating of the surface.
More heating would mean more wind would it not? and then more dust.

Or am I just “crazy”?

[neverdem]

Or am I just “crazy”?

We're all crazy or dupes of the vast right wing conspiracy.

[cabojoe]

I thought that here on Earth dust in the atmosphere cools the Earth, and dust was the explanation for last years weak hurricane season. I think some people are reaching to come to a conclusion that they want.

[SERE_DOC]

SO is this person who wrote this a spelling major?

Mars Hots up

[neverdem]

SO is this person who wrote this a spelling major?

Mars Hots up

IIRC, Nature is a British gig. Is this normal English usage in Great Britain? I don't know.

[lafroste]

"You can't take 10 years of data and extrapolate out to 1,000 years,"

Sure you can. Pseudo-scientist greenies do that sort of thing all the time, except they don't really "need" the 10 years of data. One year will do, even a lone data point, easily extrapolated over any time frame, even eons, if it supports the crisis du jour.

BTW: I bet it's the Sun heating up Mars, not the dust.

[justa-hairyape]

Excerpt from the linked article "Hot Times in the Solar System".

It is also worth noting that the Sun's radiance is measured from Earth orbit, and these records do not show it increasing over the past few decades, except with the regular rise and fall of the solar cycle.

What this sentence actually states is that scientific measurements have shown that solar radiance rises and falls with the solar cycle. That is a fact and it cannot be denied. Since that sunlight reaches every planet in the solar system, it is guaranteed to have an effect on the every planets temperature. We now know from the new and completely shocking videos of our latest satellite (Hinode-SolarB) that the sun radiance has to be varying quite a bit. How can anyone watch videos of those flares or sunspots and not reach the conclusion that solar radiance varies and is somewhat unpredictable.

[Cementjungle]

It’s absorbing heat coming off the now really, really hot earth.

[neverdem]

How can anyone watch videos of those flares or sunspots and not reach the conclusion that solar radiance varies and is somewhat unpredictable.

It's not easy work.

[justa-hairyape]

I thought that here on Earth dust in the atmosphere cools the Earth, and dust was the explanation for last years weak hurricane season. I think some people are reaching to come to a conclusion that they want.

I am always suspect of articles of any sort that appear in Science and Nature. There are just general scientific magazines and are not highly disciplined journals. What they are doing on Mars is basically the same mistake they made on Earth. They see a temperature rise and they mistake the causation for one of the symptoms. The dust is being moved around because the dark rock absorbed more light and heated up. Now instead of diagnosing the causation as heat from the sunlight, they are trying to state that the symptom (winds generated from the heat) are causing the heat. This is the same mistake they made here on earth by stating that CO2 was the causation of the temperature increase instead of recognizing that it was just a symptom. So what this shows is that faulty computer simulation models generated to analyze climate patterns here on Earth can be just as faulty when they apply them to other planets.

And you are correct that they are reaching. Occam's Razor says sunlight input must have increased. The Progressive Razor states that dark areas are growing because they warm and create heat and expose more dark areas by driving all the light colored sand into smaller piles and then instead of a runaway heating condition the whole system gets magically reset because a large super dust storm then covers most of the black areas up with lightly colored sand.

[sphinx]

The warming on Mars is likely to be seized by climate-change sceptics here on Earth - if Mars is hotting up even without any cars or pollution, then perhaps the Sun or some other natural, Solar-System-wide factor is to blame. But to infer that would be "crazy" says Christensen

This sentence is interesting. Notice how the word "crazy" -- the key message point -- is dropped in by itself. The first two clauses are truisms. I very much doubt that Dr. Christensen actually said it was "crazy" to hypothesize that warming might be driven primarily by the sun. He might very well have said it was crazy to leap to that conclusion based on events on Mars, but that is a rather different proposition. The reporter is enforcing the party line here and, I suspect, misuing Christensen to do it.

The phrase "climate change skeptics" is another tipoff. Everyone understands that the climate is changing. The argument is over how much of the change is man made as opposed to driven by natural cycles.