Snow could offset global warming in Antarctica

Jul 10, 2012
A typical view of the snow-covered Antarctic plateau. Credit: Jean-Charles Gallet, LGGE

Increased snowfall in Antarctica could offset the future impact of global warming on the continent, according to research carried out by a French team comprising researchers from the Laboratoire de Glaciologie et Géophysique de l'Environnement and the Takuvik International Joint Unit. The research reveals the existence of a hitherto underestimated negative feedback mechanism acting on temperatures. Using satellite images and numerical modeling, the researchers showed that rising temperatures in Antarctica will lead to increased precipitation and, therefore, to a 'whiter' snow that will reduce the impact of climate change at the heart of the continent. The study, published in the 1 July 2012 issue of the journal Nature Climate Change, should help to take better account of snow in models used to predict global climate change.

The amount of solar energy absorbed by the surface of the Antarctic continent is determined by the snow's albedo, in other words by its 'whiteness'. The albedo, in turn, depends on the size of the snow grains. In a process that is familiar to physicists, once the fine particles of snow are deposited on the surface they tend to become larger, at a rate that increases with temperature. The coarsening of the grains leads to a fall in albedo, which causes temperatures to rise. Climatologists have long been aware of the importance of this positive feedback mechanism.  

Changes in the size of snow grains since 1999 at the French-Italian Concordia Station in Antarctica (75°S, 123°E), as shown by microwave satellite data. The years 2002 and 2008 show a remarkably small increase in grain size. Meteorological data also indicates exceptionally high precipitation for both years. The 'grain index' introduced in this study is a combination of satellite data approximately representing the size of grains in the top few centimeters of snow cover. Credit: LGGE (CNRS / UJF)

However, according to recent experiments by researchers at the Laboratoire de Glaciologie et Géophysique de l'Environnement and the Takuvik International Joint Unit, this effect is partially offset by a hitherto underestimated negative .  Using data from satellites observing the Antarctic surface at microwave wavelengths, the scientists showed that, in summers marked by heavy snowfall, albedo did not change significantly: the surface was covered with fine snow grains that were constantly renewed. Snowfall is expected to increase in in the future and it is well known that, when temperatures are very low, the air is dry and snowfall is scarce. In Antarctica therefore, warming will also result in increased precipitation.  

According to the researchers, in a climate scenario where the temperature of Antarctica rises by 3°C, heavier would increase the albedo by 0.4%. This would offset the 0.3% fall in albedo caused by the rising temperatures (positive feedback loop). Thus, despite significant warming in Antarctica, albedo will vary only very slightly over a large part of the . Since the positive temperature-albedo feedback loop will not be established, warming in Antarctica will be lower than expected. Warming predictions should be revised downwards by 0.5°C for central Antarctica. This research highlights the need to take better account of snow in models used to predict future .

Explore further: NASA sees Tropical Storm playing polo with western Mexico

More information: Inhibition of the positive snow-albedo feedback by precipitation in interior Antarctica. G. Picard, F. Domine, G. Krinner, L. Arnaud and E. Lefebvre. Nature climate change. 1 July 2012.

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User comments : 8

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Birger
3.7 / 5 (15) Jul 10, 2012
NB: This offset is only specific to Antarctica (anticipating denial trolls claiming this shows global warming is a hoax).
rubberman
4.6 / 5 (9) Jul 10, 2012
This is good news. If proven accurate it expands the window for adaptation due to sea level rise for future generations.
EdMoore
1.9 / 5 (14) Jul 10, 2012
Birger: Anticipation doesn't negate the hoax. AGW is a fraud, a cult, a deception, a lie.
rubberman
4 / 5 (12) Jul 10, 2012
Birger: Anticipation doesn't negate the hoax. AGW is a fraud, a cult, a deception, a lie.


You have scientific proof of this Ed? Just asking because your opinion means jack s**t without it.....
NotParker
1.7 / 5 (12) Jul 10, 2012
NB: This offset is only specific to Antarctica (anticipating denial trolls claiming this shows global warming is a hoax).


This article is about albedo. "whiter" albedo cools the earth.

But the opposite is true. A darker albedo warms the earth (assuming sunshine/clouds are the same).

The Earthshine project measured earths albedo and found it got significantly darker in the 1990s. And then got a little less dark after 1998 when warming stopped.

http://i39.tinypi...c184.jpg

Which explains all warming.
rubberman
4.1 / 5 (9) Jul 10, 2012
Why does your data stop at 2003?
Oh yeah, the cherries for you to pick only grew before the polar ice cap began it's disappearing act and reversed your trend again.
This is why 9 out of the 10 warmest years since modern record keeping began have been since and include 1998....during a descent into a solar minimum.

Which explains all the warming.
Which until today you denied was happening.

NotParker
2 / 5 (8) Jul 10, 2012
Why does your data stop at 2003?


Lack of funding probably.

It doesn't make it the data go away.

And albedo changes from 1980s to 1998 (when warming stopped) caused a difference of 6.8W/m2 which is almost triple claimed for all CO2 warming from 1850.

Vendicar_Decarian
3.3 / 5 (7) Jul 10, 2012
ParkerTard's Albedo data ends in 2003.5. and yet data is available all the way up to the current year.

"The Earthshine project measured earths albedo" - ParkerTard

What is the diseased mind of ParkerTard trying to hide?