Arctic warming linked to combination of reduced sea ice and global atmospheric warming

Jul 06, 2012

( -- The combination of melting sea ice and global atmospheric warming are contributing to the high rate of warming in the Arctic, where temperatures are increasing up to four times faster than the global average, a new University of Melbourne study has shown.

Professor Ian Simmonds from the University of Melbourne’s School of Earth Sciences co-authored the study and said the new information showed this combined effect at both ground and atmospheric level played a key role in increasing the rate of in the .

“Loss of contributes to ground level warming while global warming intensifies atmospheric circulation and contributes to increased temperatures higher in the Arctic atmosphere,” Professor Simmonds said.

Lead author, Dr James Screen of the School of Earth Sciences at the University of Melbourne said the sea ice acted like a shiny lid on the Arctic Ocean.

“When it is heated, it reflects most of the incoming sunlight back into space.  When the sea ice melts, more heat is absorbed by the water.  The warmer water then heats the atmosphere above it,” he said.

Professor Simmonds said as temperatures increase across the globe, so does the intensity of atmospheric circulation.

“This circulation transports energy to the Arctic region, increasing temperatures further up in the atmosphere,” he said.

“Water vapour is a very strong greenhouse gas. As the atmosphere warms it can hold more moisture, which acts as a positive feedback signal, increasing the greenhouse effect.  However, in the cold Arctic where there is less moisture in the air, this positive feedback is much weaker hence the ‘direct’ greenhouse effect is smaller in the Arctic than elsewhere.

“Even though the Arctic region has a relatively small , the effect of the melted ice combined with greater transports of heat from the south are more than enough to make up for this modest ‘local’ greenhouse warming.”

The study was published in the prestigious Geophysical Research Letters and featured in Nature as one of ‘The most viewed papers in science’.

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User comments : 9

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2.3 / 5 (18) Jul 06, 2012
Water vapour is a very strong greenhouse gas." True. Now for some climate change fun:

We should ban boiling water. Perhaps add an all countries shared U.N. tax for ocean evaporation?

3.5 / 5 (13) Jul 06, 2012
Great straw man argument, and great way to show how little you know about science.

2.5 / 5 (13) Jul 06, 2012
I think one of the byproducts of fuel cells is water vapor...isn't it?
3.9 / 5 (11) Jul 06, 2012
Sigh... One of the things that allows this planet to have our kind of life is the ability of water to exist in three phases. Most planets do not have the temperature range necessary. Because of this temperature range, water is transported around the globe and is a locally (weather) dependent variable. CO2 does not exist as anything other than a gas in this planets atmosphere (or in solution). Consequently, it is a globally dependent variable and has been steadily increasing in the atmosphere due to human instigated production. Water vapor will come and go with the weather but CO2 continues to increase. Water vapor will also provide feedback as a potent GHG as the local temperatures increase. Of course all of this is complicated by clouds which are being worked on but have not been solved yet. So, the idea that one should curb water vapor emissions is a "red herring" and has no meaning from a scientific standpoint.
2.7 / 5 (12) Jul 06, 2012
Denialists are full of all manner of idiotic ideas.

"We should ban boiling water" - PsyTard

Atmospheric H2O content is not determined by how many pots are boiling, but by the ambient temperature of the air. Warmer air holds more water, and if the air cools and can no longer hold that water if condenses out as rain.

Boiling kettles no more increase atmospheric H2O levels tan boiling kettles produce clouds.
1.9 / 5 (14) Jul 06, 2012
CO2 increased without any help from human during the last interglacial - the Eemian. It followed the temperature rise. It did not cause it.

And then the Eemian ended and temperature went down and CO2 went down and the ice age returned.

Warming caused CO2 to leave the oceans.

No fossil fuels involved.

Just like now.
2.2 / 5 (10) Jul 06, 2012
VD--Don't you know anything about American jokes?
Calm down!
4.4 / 5 (7) Jul 07, 2012
CO2 increased without any help from human during the last interglacial - the Eemian. It followed the temperature rise. It did not cause it.

And then the Eemian ended and temperature went down and CO2 went down and the ice age returned.

Warming caused CO2 to leave the oceans.

No fossil fuels involved.

Just like now.

This all well known and accepted NP (except the last bit). No humans factored in and orbital changes you know.

Finally got to grips with Milankovich cycles eh?

First though, CO2 rose after the end of the ice age because that is the natural order of things. Now humans are adding it unnaturally. Whether orbital warming or CO2 comes first the effect is always more warming. Got it?
Also, an inconvenient fact, CO2 isn't leaving the oceans - on the contrary it's sinking into them. Ph levels are falling. ie becoming more acidic. That cannot happen if oceans are giving up CO2 to the atmosphere. Unless you want to claim that CO2 enters at the ocean bed.
1 / 5 (2) Jul 12, 2012
Water vapor will come and go with the weather but CO2 continues to increase.

Is there some maximum saturation point for water vapor though? I'm not really asking this re: human production of water vapor, but more from an academic standpoint. It seems that you will at times, on average, have more or less water vapor in the atmosphere. It all depends on how long those "times" last and the range of the levels themselves. I do know it's far more efficient than CO2 as a GHG so it seems that even a range of a few percent could substantially effect the temperature...

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