Nature publishes Mars global warming paper


Tonington
#1
Dust storms turn up the heat on Mars


04/04/2007 5:01:03 PM

Earth is not the only planet in the solar system showing the effects of global warming, according to a study published on Wednesday.




A rise in wind-swept dust on Mars is causing more heat from sunlight to be absorbed by the planet's surface, leading to rising temperatures, according to a study published in the British journal Nature.

Surface air temperatures increased by 0.65 degrees C over a 20-year period, the authors said, based on computer models comparing changes in the planet's surface brightness. Light-coloured dust lying on the surface of the planet usually reflects the sun's light back into space in a process called albedo. But high winds can churn up this dust and expose the planet's darker soil to the sun's rays.

On Mars, one of the key factors in planetary warming is the change caused by the darkening of its surface, according to the team led by NASA planetary scientist Lori Fenton. Fenton and her colleagues collected data from two sources: an albedo map from the 1970s produced by an infrared thermal mapper onboard NASA's Viking probe and a more recent map from 1999-2000 taken by a sensor aboard the Mars Global Surveyor probe.

The researchers found that the darker soil absorbs more light and traps heat in the atmosphere, which in turn causes more turbulence that creates more wind storms. This "positive feedback loop" is similar to a predicted cycle expected to affect Earth's glaciers: higher temperatures will melt glaciers, which will in turn reduce the amount of reflective ice, trapping more heat and leading to even higher temperatures.

"Results indicate enhanced wind stress in recently darkened areas and decreased wind stress in brightened areas, producing a positive feedback system in which the albedo changes strengthen the winds that generate the changes," the authors say in the study. But the process and causes of planetary warming on Mars share little in common with Earth.

Mars has a much thinner atmosphere, lacks Earth's cloud cover and doesn't have either vegetation or active volcanoes to release greenhouse gases that might trap heat and warm the planet. Mars also doesn't have any of the man-made factors that a UN-led report on climate change (which was backed by 2,000 climate scientists from 113 countries) said in February were "very likely" behind rises in Earth's average annual temperatures.

By comparison, the dust storm initiation process responsible for and caused by rising temperatures is a phenomenon unique to Mars, the researchers write. The rise in temperature also wouldn't help make the planet any more livable for humans. Although midsummer temperatures on the planet can reach 26 C, they can also drop to a numbing -111 C.

http://news.sympatico.msn.cbc.ca/Sci...e=true&abc=abc
 
L Gilbert
#2
-111 C is only "numbing"? Hmmm
So maybe -273 is only "freezing".
 
#juan
#3
Quote: Originally Posted by L Gilbert View Post

-111 C is only "numbing"? Hmmm
So maybe -273 is only "freezing".

And then only to brass monkeys.....
 
Tonington
#4
I was actually surprised that there weren't others here who found this first. I thought it would have made it's way around the blogosphere by now...
 
L Gilbert
#5
It did. Actually the idea that darker attracts energy and lighter reflects it isn't a new one.
 
Tonington
#6
No not at all. I know before this paper came out there was a plethora of posters here who were bringing this exact same thing up.

What I find interesting is how skeptics will berate our climate models and say our measurements don't go back far enough, then bring up something like this to support their disbelief in current climate science. This study which is all MODEL, and only uses temperature measurements from the 70's and 99-2000. Meanwhile our models here have temperature data going back 1oo some odd years, and even further when analyzing the evidence left by the feedbacks. The models use all of this plus present day greenhouse effect with the plethora of natural phenomena to reproduce the climate observations we see now...

Not to mention the differences between Mars climate and ours...
 
L Gilbert
#7
I knew that. Really I did.
 
Tonington
#8
I believe yah
 
s243a
#9
Of course they published it. They wanted to blame it on something other then the sun. Of course what causes more dust storms? (wind). Where does wind power from? (the sun)
 
Tonington
#10
Hey I'm not disputing the fact they published this paper. What the paper actually highlights is how changes in Albedo can affect the temperature.

The changes in the suns irradience can't be taken on Earth, theres too much interference. Measurements taken from space avoid that problem, and since 1978 when the measurements began there has been no change. The Max Planck institute and also the World Radiation Center says there have been no measured differences since the 40s.

Notice the variability before 1978, because of the proxy data they have to use.
 
lysyfacet
#11
well reading all that was very interesting, and i learned a few new things . I always find work published to do with the solar system veyr interesting. It really gets me thinking about whats actually out there
 
s243a
#12
Quote: Originally Posted by Tonington View Post

The Max Planck institute and also the World Radiation Center says there have been no measured differences since the 40s.

Find on their website where they say that. Here is a link to their website.


" Does the Sun affect climate?


The Sun can influence the Earth's environment in a variety of ways and on different time scales.
  • Since the Sun is by far the largest supplier of energy to the Earth's surface, any change in the radiative output of the Sun also affects the energy balance of the Earth's surface.
  • Also, changes in the solar spectrum, in particular in the UV, could enhance this influence by affecting stratospheric chemistry: most importantly the balance between ozone production and destruction. Although the UV radiation shortward of 300 nm contributes less than 1% to the magnitude of the total solar irradiance, it is responsible for about 10-20% of the variation of the total irradiance.
  • Finally, the Sun may influence the Earth's climate also in other, more convoluted ways, e.g. by modulating the flux of cosmic rays, which have been proposed to increase the coverage by low-lying clouds.
"
http://www.mps.mpg.de/projects/sun-c.../sunearth.html
 
Tonington
#13
Heres the page with the graph, which shows the solar irradiation unchanged, which I allready posted.
http://www.mps.mpg.de/en/projekte/sun-climate/
And this is a paper released by Max Planck researchers, where they note that:
We show that at least in the most recent past (since about 1970) the solar influence on climate cannot have been significant.
http://www.mps.mpg.de/homes/natalie/PAPERS/asr2004.pdf

Note I'm not saying the sun plays no part. Just that observed irradiance has been relatively unchanged, especially when people try to correlate it to the rise in temperature.
 

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