By mid-century, more Antarctic snowfall may help offset sea-level rise

August 24, 2016, Columbia University
Snowfall is expected to increase over Antarctica as temperatures warm. Credit: Michael Stukel

When Antarctica's air temperature rises, moisture in the atmosphere increases. That should mean more snowfall on the frozen continent. So why hasn't that trend become evident in Antarctica's surface mass balance as climate models predict?

In a new study, scientists used historical records and climate simulations to examine that question. They found that the effect of rising temperatures on snowfall has so far been overshadowed by Antarctica's large natural climate variability, which comes from random, chaotic variations in the polar weather. By mid-century, however, as temperatures continue to rise, the study shows how the effect of human-induced warming on Antarctica's net snow accumulation should emerge above the noise.

The expectation of more snowfall is something of a silver lining as temperatures rise. Global warming is already increasing sea level through melting ice and thermal expansion. The increase in snowfall over Antarctica could help reduce the amount of rise by 51 to 79 millimeters, or about 2 to 3 inches, by the year 2100, according to the study. That would be a small but important benefit: the Intergovernmental Panel on Climate Change estimates global will be at least 10 times that by 2100 under the same high-emissions scenario used in the new study.

"Increased snowfall over Antarctica is the sole process connected to that is thought to have a significant mitigating effect on global sea level rise," said lead author Michael Previdi, a professor at Columbia University's Lamont-Doherty Earth Observatory. "While the magnitude of this effect is uncertain, it is likely that the balance of different processes determining Antarctica's net contribution to global sea level rise will be decidedly different in the future than it has been in the recent past."

On a continental scale, surface mass balance is the difference between the amount of that accumulates and the amount of snow lost to sublimation. It affects global because the amount of water on earth is essentially constant, so when more water is stored as snow or ice on land, less water is available to contribute to rising seas.

Antarctica's annual mean surface mass balance estimated using CMIP5 climate models. Future snowfall increases will also likely be largest around the edges of the continent, where storms blow in and temperatures tend to be warmer. Credit: Previdi and Polvani, 2016.

For the study, published this week in the journal Environmental Research Letters, Previdi and co-author Lorenzo Polvani of Lamont-Doherty Earth Observatory evaluated surface mass balance simulations from 35 coupled atmosphere-ocean climate models, which simulate the physical forces that affect Antarctica.

The models allow scientists to quantify both the human influence on surface mass balance and the influence of natural variability. The scientists found that from 1961 to 2005, global warming increased Antarctica's surface mass balance by 124 billion tons per year, smaller in magnitude than natural year-to-year variability, which was found to be plus or minus 126 billion tons per year.

When the scientists looked at all 35 models, 46 percent of the individual simulations showed a statistically significant trend in surface mass balance from 1961 to 2005, the year that most of the models' historical simulations end. The likelihood of seeing a statistically significant trend in surface mass balance rises as the models forecast ahead in time. After 2015, the models cross a threshold where it becomes "likely," with a 66 percent chance, that evidence of anthropogenic climate change will emerge in Antarctica's surface mass balance. By 2040, it becomes "very likely," with a higher than 90 percent chance.

Previdi and Polvani repeated their analysis with different emissions scenarios and also considered surface mass balance trends starting in 1979, at the dawn of the satellite era. The analyses showed similar results, with the global warming signal "very likely" to emerge by mid-century.

"The apparent discrepancy between models and observations can be easily reconciled by considering the large surface mass balance variations generated naturally within the Antarctic climate system," they write.

Previous studies also found no significant change in the total Antarctic surface mass balance in recent decades, though a 2013 ice core study found a 10 percent increase in surface mass balance in coastal regions since the 1960s. All temperature records, meanwhile, indicate that Antarctica warmed from 1961 to 2005. Ice cores also show a strong relationship between the continent's surface and temperature changes through history, including the end of the last ice age when temperatures rose dramatically.

Explore further: Will more snow over Antarctica offset rising seas? Don't count on it

More information: "Anthropogenic Impact on Antarctic Surface Mass Balance, Currently Masked by Natural Variability, to Emerge by Mid-Century," Environmental Research Letters, 2016. iopscience.iop.org/article/10. … 748-9326/11/9/094001

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18 comments

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Steve Case
1.1 / 5 (7) Aug 24, 2016
So Antarctica is gaining ice. Is that right?
Caliban
5 / 5 (6) Aug 24, 2016
You could try reading the article. The answer to your question is spelled out in it --within error bars, of course.
Omnishambles
1 / 5 (7) Aug 25, 2016
So...46% of the models indicate a significant trend in surface mass balance that doesn't exist. Has it ever occurred to the authors that perhaps the modelling is incorrect?
Maggnus
4.2 / 5 (5) Aug 25, 2016
So...46% of the models indicate a significant trend in surface mass balance that doesn't exist. Has it ever occurred to the authors that perhaps the modelling is incorrect?


You could try reading the article. The answer to your question is spelled out in it --within error bars, of course.


antigoracle
1 / 5 (8) Aug 25, 2016
So why hasn't that trend become evident in Antarctica's surface mass balance as climate models predict?

LOL.
Astonishing isn't it? The more BILLIONS of your tax dollars the AGW Cult squander on their climate models, the further from reality they find themselves. Seriously, it would be so much cheaper to just peer into their CO2 filled crystal ball for the same doom and gloom.
691Boat
5 / 5 (9) Aug 25, 2016
So why hasn't that trend become evident in Antarctica's surface mass balance as climate models predict?

LOL.
Astonishing isn't it? The more BILLIONS of your tax dollars the AGW Cult squander on their climate models, the further from reality they find themselves. Seriously, it would be so much cheaper to just peer into their CO2 filled crystal ball for the same doom and gloom.


The answer you are seeking is summarized in the second paragraph of the article. If you keep reading past the intro, you tend to learn things.
antigoracle
1 / 5 (7) Aug 25, 2016
The answer you are seeking is summarized in the second paragraph of the article. If you keep reading past the intro, you tend to learn things.

LOL.
Another Chicken Little, who imagines that they can read. If only it could grow a brain and actually read and comprehend. After decades of preaching that AGW Cult "science" confirms globull warming is melting the Antarctic and it will drown us all, the cult's "science" now claims, globull warming is increasing the ice. The fact is that the Antarctic has been cooling for decades despite increasing CO2. AGW Cult "science" is about wasting BILLIONS just making contradicting shite up one after another as reality defies their dogma of doom and gloom.
https://www.googl...fs6ZqQDg
Phys1
4.3 / 5 (6) Aug 25, 2016
@ignoracle
So you think you are a genius surrounded by brainless illiterate chicken little retards.
Are you permanently in this state of mind or do you also have dark periods ?
EnricM
5 / 5 (4) Aug 26, 2016
So Antarctica is gaining ice. Is that right?


If you have a time machine and are writing just now from 2100 then yes, if you are just a normal mortal living in 2016 then Nope.

EnricM
5 / 5 (5) Aug 26, 2016
So...46% of the models indicate a significant trend in surface mass balance that doesn't exist. Has it ever occurred to the authors that perhaps the modelling is incorrect?


Nooo, they were waiting for you to tell them.
antigoracle
1 / 5 (6) Aug 26, 2016
So Antarctica is gaining ice. Is that right?


If you have a time machine and are writing just now from 2100 then yes, if you are just a normal mortal living in 2016 then Nope.


Yet another Chicken Little turd pops up from the depths of its cesspool of ignorance with a "gem". If only it could grow a brain.
NASA Study: Mass Gains of Antarctic Ice Sheet Greater than Losses
http://www.nasa.g...n-losses
gkam
2.1 / 5 (7) Aug 26, 2016
anti, please get help for your nastiness. You have made no points here and gotten no supporters. You are like an anonymous tagger, a vandal.

Go back to spraycans.
TheGhostofOtto1923
5 / 5 (4) Aug 26, 2016
anti, please get help for your nastiness. You have made no points here and gotten no supporters
Well neither do you. Youre ranked about the same.
freeiam
1 / 5 (4) Aug 27, 2016
"The answer you are seeking is summarized in the second paragraph of the article. If you keep reading past the intro, you tend to learn things."

So, they cannot find it, but it must be there...
Wow.
Caliban
5 / 5 (3) Aug 28, 2016

So, they cannot find it, but it must be there...
Wow.


A too-clever-by-half way of misstating the problem. How about this:

"I ought to have 23 million in my account, but it's not there....I better keep trying to find it."

That's prolly just a mite more appropriate way of conceptualizing the problem, given your worldview.

antigoracle
1 / 5 (2) Aug 28, 2016

So, they cannot find it, but it must be there...
Wow.


A too-clever-by-half way of misstating the problem. How about this:

"I ought to have 23 million in my account, but it's not there....I better keep trying to find it."

That's prolly just a mite more appropriate way of conceptualizing the problem, given your worldview.


Uh huh. You prolly should have a brain too, but it's not there....
leetennant
5 / 5 (3) Aug 28, 2016
I find it endlessly astonishing how an article based on the reality of rising temperatures and sea levels could be seen as an argument *against* warming by somebody. This is like saying we anticipated the human immune system might counteract some of the damage done to the body by smoking and then using the fact it doesn't as evidence against smoking doing the damage in the first place.

The patient? Still dying, folks.
Caliban
5 / 5 (1) Aug 29, 2016

So, they cannot find it, but it must be there...
Wow.


A too-clever-by-half way of misstating the problem. How about this:

"I ought to have 23 million in my account, but it's not there....I better keep trying to find it."

That's prolly just a mite more appropriate way of conceptualizing the problem, given your worldview.


Uh huh. You prolly should have a brain too, but it's not there....


goaticle,

Did you "forget" that you've got my comments on ignore?

Or is that tiny, carbuncle-brain of yours no longer even capable of remembering your lies?

Or is it that you grow querelous from shifting about in that soiled diaper, while you await your overdue Nursie?

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