Re: Climategate - criminal charges may follow


"Scotty" <nobody@xxxxxxxx> wrote in message
news:i5spi59la2k5u7h3of08tk053f5ushsf35@xxxxxxxxxx
Well, there you go.
I'm for Mars then.

No escape for the wicked:
http://news.nationalgeographic.com/news/2007/02/070228-mars-warming.html

Martian climate is primarily driven by dust and albedo and there is little
empirical evidence that Mars is showing long term warming.


The primary empirical evidence for long term, global warming on Mars comes
from Fenton 2007. Fenton compared a composite snapshot of Mars from 1977
taken by the Voyager spacecraft to a 1999 image compiled by the Mars Global
Surveyor (referencing work from Geissler 2005). The 1977 snapshot showed a
brighter planet. In 1999, the planet had a lower albedo, with prominent
darker regions in the southern mid and high latitudes. Using the albedo
changes in a general circulation model, Fenton calculated a 22 year global
warming trend of 0.65°C.

Fenton attributed the warming to surface dust causing a change in the
planet's albedo. Martian dust plays a major role in the planet's climate
(Kahn 1992). Solar variations are not the main driver of Martian climate.
Nevertheless, an important question remains: is the interpretation of long
term global warming on Mars correct?

A broader view of Martian climate change
To put these results in proper perspective, an understanding of what drives
Martian climate is required. Global dust storms increase the surface albedo
by settling brighter dust on dark surfaces. Within a year after a dust
storm, various wind systems remove the dust and Mars returns to a normal,
lower albedo.

The 1977 snapshot was taken after a global dust storm had deposited dust
over the southern latitudes, lightening the planet surface. Before the
storm, the planet had albedo comparable to recent measurements (Szwast
2006).

Fenton drew conclusions about long term climate by comparing two end points.
This led to the classic error of mistaking weather for climate (similar to
the recent global cooling argument). When you look at the broader data,
there is no discernable long term trend in albedo:


The apparent long-term warming between the 1970's and 1990's is largely a
consequence of the timing of the two snapshots used. The "brighter" 1977
snapshot was immediately after a global dust storm when the planet was
temporarily lighter. The "darker" 1999 snapshot was of the planet in it's
usual state. There is little evidence that Mars is undergoing decadal-scale,
long term global warming. In fact, following the 2001 global dust storm, the
southern hemisphere was brighter than in 1977 (Szwast 2006).

Conclusion
The empirical evidence isn't conclusive on whether global warming is
happening on Mars. However, to answer the question on whether the sun is
causing Earth's global warming, there is plentiful data on solar activity
and Earth's climate. Many papers have examined this data, concluding the
correlation between sun and climate ended in the 70's when the modern global
warming trend began.

So the argument that Martian warming disproves anthropogenic global warming
fails on two points - there is little empirical evidence that Mars is
warming and Mars' climate is primarily driven by dust and albedo, not solar
variations.


.

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