[meteorite-list] Science of Global Climate Modeling Confirmed by Discoveries on Mars

[Ron Baalke]

NEWS RELEASE FROM THE PLANETARY SCIENCE INSTITUTE

FROM:
Alan Fischer
Public 
Information Officer
Planetary Science Institute
520-382-0411
520-622-6300
fischer at psi.edu

Science of Global Climate Modeling Confirmed by Discoveries on Mars

Oct. 16, 2012, Tucson, Ariz. and Reno, Nev. -- Scientific modeling methods 
that predicted climate change on Earth have been found to be accurate on Mars 
as well, according to a paper presented at an international planetary 
sciences conference Tuesday.

An international team of researchers from the Planetary Science Institute in 
Tucson, working with French colleagues, found that an unusual concentration of 
glacial features on Mars matches predictions made by global climate 
computerized models, in terms of both age and location.
  
PSI Senior Scientist William K. Hartmann led the team, which included Francois 
Forget (Université Paris), who did the Martian climate modeling, and Veronique 
Ansan and Nicolas Mangold (Université de Nantes) and Daniel Berman (PSI), all 
of who analyzed spacecraft measurements regarding the glaciers.
  
"Some public figures imply that modeling of global climate change on Earth is 
'junk science,' but if climate models can explain features observed on other 
planets, then the models must have at least some validity," said team leader 
Hartmann.
  
Hartmann presented the report, "Science of Global Climate Modeling:  Confirmation 
from Discoveries On Mars," at the annual meeting of the Division of Planetary 
Sciences of the American Astronomical Society in Reno, Nev. 
  
The scientific team reached their conclusions by combining four different 
aspects of Martian geological mapping and Martian climate science in recent 
years.  They noted that the climate models, the presence of glaciers, 
the ages of the glacial surface layers, and radar confirmation of ice 
in same general area, all gave consistent results - that the glaciers 
formed in a specific region of Mars, due to unusual climate circumstances, 
just as indicated by the climate model.

The work has a long background. As early 1993, astronomers analyzed the changing 
tilt of Mars' rotational axis and found that during high-tilt Martian episodes, 
the axis tilt can exceed 45 degrees. Under this extreme condition, the summer 
hemisphere is strongly tilted toward the sun, and Mars' polar ice cap in that 
hemisphere evaporates, increasing water vapor in the Martian air, thus 
increasing the chances for snowfall in the dark, cold, winter hemisphere. 
The last such episodes happened on Mars 5 million to 20 million years ago.

By 2001-2006, various French and American researchers applied the 
global climate computer models to study this effect. The computer programs 
were originally developed for planet Earth to estimate climate effects, 
from hurricane paths to CO2 greenhouse warming. Planetary scientists simply 
applied the Martian topography, atmosphere, and gravity, in order to run 
the computer calculations for Mars. The calculations indicated a strong 
concentration of winter snow and ice in a mid-latitude southern region 
of Mars, just east of a huge Martian impact basin named Hellas.

At the same time, the PSI scientists independently discovered an unusual 
concentration of glacial features in a 40-mile-wide crater named "Greg" 
centered in the same region.  Their analysis showed that the surface layers 
of the glaciers formed at the same time as the predicted climate extremes, 
about 5 million to 20 million years ago.
  
"The bottom line is that the global climate models indicate that the last 
few intense deposits of ice occurred about 5 million to 15 million years ago, 
virtually centered on Greg crater, and that's just where the spacecraft 
data reveal glaciers whose surface layers date from that time," Hartmann 
said. "If global climate models indicate specific concentration of ice-rich 
features where and when we actually see them on a distant planet, then 
climate modeling should not be sarcastically dismissed.  Our results provide 
an important, teachable refutation of the attacks on climate science on our 
home planet."


Images and maps supporting the paper are available at 
http://www.psi.edu/news/hartmanndps.html

A web-based photo tour of Greg Crater is available at 
http://www.psi.edu/~hartmann/Greg_crater.html



CONTACT:
William 
K. Hartmann
Senior Scientist
hartmann at psi.edu

PSI INFORMATION:
Mark V. 
Sykes
Director
520-622-6300
sykes at psi.edu