From THE EARTH INSTITUTE AT COLUMBIA UNIVERSITY
By mid-century, more Antarctic snowfall may help offset sea-level rise
Increasing precipitation masked by natural variability — for now
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 global sea level 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 sea level rise 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 global warming 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 snowfall that accumulates and the amount of snow lost to sublimation. It affects global sea level 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.
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 mass balance and temperature changes through history, including the end of the last ice age when temperatures rose dramatically.
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The paper, “Anthropogenic Impact on Antarctic Surface Mass Balance, Currently Masked by Natural Variability, to Emerge by Mid-Century,”
http://iopscience.iop.org/article/10.1088/1748-9326/11/9/094001
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The first sentence raises some queries
“When Antarctica’s air temperature rises, moisture in the atmosphere increases.”
If the temperature rises from – 50 to – 40 I have trouble understanding how moisture in the atmosphere will increase.
When ‘moisture’ enters a space where the temperature is below zero, one way or another it turns to ice.
One of the most hilarious claims made by the Warmists was that last February was the ‘warmest ever’ because an incursion of warm air into the Arctic raised the temperature from Minus 30˚C to Minus 20˚C!
i.e. there was an increase in snowfall and ice formation…now that’s what I call global warming!
Only if the air volume has a relative humidity at or over 100%. There is always water present in an air volume if there is a source of water nearby, even if the source is a block of ice. Leave a block of ice in a box with air in it at -30C or so for a bit. Withdraw an air sample. You will find water in it. Not a lot, but some. The absolute humidity will be quite low.
We should all be familiar with freezer burn. The ice in frozen food in the freezer basically evaporates. The technical term is sublimation but it’s the same idea as evaporation in that molecules turn to gas.
For sure, the main process in the freezer is that most of the water vapor in the air turns to ice. That’s why we have to defrost the freezer. That cold air can still hold a little bit of moisture and we can’t ignore that fact. If we don’t wrap our steak properly, it will freezer burn.
Sublimates rather than evaporates but otherwise, right on.
The clearest problem is that the argument is false to empirical reality. One, possibly the only, distinction between Pleistocene and Holocene climate (aside of course from the absence those big, cold, white thingies) is that during the Pleistocene there is a positive correlation between temperature and precipitation in ice core data from both Antarctica and from Greenland. At the beginning of the Holocene, the relation between temperature and snow accumulation in ice core data from both hemispheres inverts. It literally change sign, becoming negative at the shift between the two periods and seems to diverge increasingly toward the present.
It will but negligibly .
I have heard rumors that Antarctica is completely surrounded by oceans that are much warmer than is the continent, and that a lot of water can evaporate from those oceans, and blow over to deposit on Antarctica.
Just where the hell did all of the ice on Antarctica come from anyhow, was it sublimation from some subterranian water source ? Must have come from somewhere other than Antarctica, and I suspect that is likely to continue long after the good professor has retired.
G
More studying models. What about the actual measurements?
Tom Halla, there is a NASA study from 2015 using measurements. Based on satellite data they found for the periods 1992-2001 and 2003 tot 2008 a net GAIN in the Antarctic ice volume:
http://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses
“Oct. 30, 2015
NASA Study: Mass Gains of Antarctic Ice Sheet Greater than Losses
A new NASA study says that an increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers.
The research challenges the conclusions of other studies, including the Intergovernmental Panel on Climate Change’s (IPCC) 2013 report, which says that Antarctica is overall losing land ice.
According to the new analysis of satellite data, the Antarctic ice sheet showed a net gain of 112 billion tons of ice a year from 1992 to 2001. That net gain slowed to 82 billion tons of ice per year between 2003 and 2008.
(…..)
The study analyzed changes in the surface height of the Antarctic ice sheet measured by radar altimeters on two European Space Agency European Remote Sensing (ERS) satellites, spanning from 1992 to 2001, and by the laser altimeter on NASA’s Ice, Cloud, and land Elevation Satellite (ICESat) from 2003 to 2008.
(….)
The extra snowfall that began 10,000 years ago has been slowly accumulating on the ice sheet and compacting into solid ice over millennia, thickening the ice in East Antarctica and the interior of West Antarctica by an average of 0.7 inches (1.7 centimeters) per year. This small thickening, sustained over thousands of years and spread over the vast expanse of these sectors of Antarctica, corresponds to a very large gain of ice – enough to outweigh the losses from fast-flowing glaciers in other parts of the continent and reduce global sea level rise.
Zwally’s team calculated that the mass gain from the thickening of East Antarctica remained steady from 1992 to 2008 at 200 billion tons per year, while the ice losses from the coastal regions of West Antarctica and the Antarctic Peninsula increased by 65 billion tons per year.
(….) “
http://www.nasa.gov/sites/default/files/thumbnails/image/figure-dmdt-map.png
The link to the study on the nasa page is broken. Here’s the correct one:
http://www.ingentaconnect.com/search/article?option1=tka&value1=mass+gains+of+antarctic+ice+sheet&pageSize=10&index=1
So how long until the continent tips over?
Because, just like a lot of young people today, they’d rather sit on their backsides playing computer games than go out and do some actual work. Instead of seeking the truth, they, like young people chasing Pokemon, seek a fictitious, fabricated bogeyman.
Tom, it’s models all the way down!
WHAT “sea-level rise?” 2 mm? Isn’t this about as productive as debating the number of angels that can dance on the head of a pin? Time this nonsense was DE-FUNDED.
“When the scientists looked at all 35 models, 46 percent of…. ” yada, yada, yada. Science by consensus.
last I taught, 46% was an “F”
Measurements cannot tell you what will happen in the future. Science is about making models to
predict events. Of course to make a good model you need good data but if you want to answer the
question “what will our climate be like 100 years from now” you need to study models. Even the
answer “the same as it is today” implicitly relies on a model of the Earth’s climate that may or may not
be accurate.
You have to wait till the future to get good data on what happened in the future.
That’s the nature of data; you can’t have it till it happens.
G
I dealt with another study like this, First water needs to be evaporated, then transported over the pole then it’s got to rain out. Usually the energy balance is wrong.
Any paper that uses RCP8.5 is instantly suspect!
“The models allow scientists to quantify both the human influence on surface mass balance and the influence of natural variability.”
I would fire anyone who tried to say that. I would however award high marks for managing to assert so many wrongs in such a small space.
“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 …“. Horse feathers. What they actually found was that they had no idea how the Antarctic weather or climate operates. Any genuine scientist would have no difficulty in admitting that, but these pathetic ignoramuses just hide behind “random, chaotic”. Since the missing knowledge is also missing from the models, it follows that all model findings are totally useless.
[Cambridge dictionary: Pathetic = unsuccessful or showing no ability, effort, or bravery, so that people feel no respect. Ignoramus = a person who knows nothing. I don’t think those words are out of place in this context.]
Huge climate variability which, now that they have modeled the situation, will obediently stop being variable in order to reveal the received wisdom of the mother church. BS and that doesn’t mean bachelor of science.
The scale on the x-axis, “water equivalent in millimeters per year”, is one of the most contrived I have ever seen.
It’s not linear, not logarithmic, not really anything except designed to fit several different shades on the map such that an appreciable area given to each shade. In non-climate sciences it might at best be described as not conveying a helpfully accurate description of the way the precipitation data is really distributed across the continent.
It is approximately logarithmic. Each interval is roughly (very roughly) twice to three times the previous.
Michael Hart- agree, the scale is contrived to “…described as conveying a false description of the way precipitation date is really distribute….”. An area map is used to display data, in this case the amount of precipitation. Using a variable scale simply falsifies the real data and makes the map useless, except as a bit of propaganda.
other errors(besides using models with a poor choice of RCP8.5 as an assumption) is: “It affects global sea level because the amount of water on earth is essentially constant”. Who, when, and where has this been published. I cannot see a plausible way to show this since the earth collects water and other mass from meteors on a daily basis and various gases, primarily hydrogen, evaporate into space from the outer atmosphere.
Another problem: “When Antarctica’s air temperature rises, moisture in the atmosphere increases. That should mean more snowfall on the frozen continent”. Well, yes, air with a higher temperature can hold more moisture but at typical temperatures the coastal regions(slightly above freezing) can carry enough moisture to snow. Mostly this moisture either arises locally or is carried in by storms and snows out on the edge glaciers. Further inland with temperatures trending down to -12degC the air can’t carry significant amounts of moisture. This is reflected in the average snowfall in the interior falling to a few inches a year.
At -40 degC the humidity ratio(grams of water/grams of dry air) goes down into the range of .000002.
The average altitude of Antarctica is above 10,000 feet. So at that lower atmospheric pressure and sub zero Temperatures down to -94 deg. C at times I don’t expect a lot of rain.
g
What a load of old shoes. The ongoing fall in sea levels in my tectonically stable part of the world is already the result of an increase in ASMB. Why don’t they spend their time doing a detailed tectonic audit of the worlds tide gauges and then get back to us on the real state of SLR.
(Why don’t they spend their time doing a detailed tectonic audit of the worlds tide gauges and then get back to us on the real state of SLR…….)
Good one spangled drongo!
How about establishing a new datum for determining MSL. The top of Mount Everest for example. That would immediately ’cause’ MSL to fall at the speed of a growing fingernail. Folks in Miami and the Marshall Islands could sleep at night without fear of innundation..?
It’s all relative after all, the problem is relative to what?!
Bahamamike
Models? Scientists? Human influence?
Humans don’t control the sun, however, the sun controls the climate.
This is a nonsense paper by activists!
It would be nice to know how the sun controls the climate, if it does, as I suspect.
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Here you go:
http://www.acrim.com/
It just goes to prove, that once again, we are all doomed…
‘ 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.’
Amazing.Something new. /sarc
What a shock to discover nature. More shocks to come.
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“All temperature records, meanwhile, indicate that Antarctica warmed from 1961 to 2005.”
A citation to some of those records would have been useful, The records I find at HadCrut4 show Antarctic temperature unchanged since 1955.
Rob,
That was my reaction also.
Cold hard fact is that nobody has been able to attribute change to natural versus anthropogenic.
Those who think that physics models can differentiate are not credible.
Geoff
I think I remember one set of data that showed warming prior to 1969 (Steig?). They may be taking that warming and smearing it over the entire period. Certainly satellites have shown no warming since 1979. So, why would they expect much in the way to added snowfall when there hasn’t been any warming for 40-50 years? Oh Yeah, the Southern Ocean has been cooling for the last 2 decades which also should mean less evaporation.
DHR
Also my reaction to “All temperature records, meanwhile, indicate that Antarctica warmed from 1961 to 2005.”
Whose records would those ‘all’ be? There has been some natural variability over the past 60 years but nothing to write home about and no statistically significant trend. At all.
When I read that 126 is bigger than 124 and there is a hint that there is something significant about the difference I know the authors are not clear what these numbers mean and how uncertain they are.
” 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.”
translation:
There is no evidence of human induced warming found here and don’t bother looking for 30 years or so.
+1 to that. If temperatures continue to ‘rise’ as they have over the past 20 years, exactly nothing will happen. By 2100 the alarmists will have finally run out of excuses. What a great day that will be.
Serfs get a day off.
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Actually, the Y2.1K people will be raising alarm that the Personal Robots built before 2081 will shut down when their calendars change.
Still amazed that they’d put this ameliorating meme out into public consciousness. The study showing increased ice accumulation over Antarctica must have really thrown them for a loop.
The desperation is strong, what with this bollixed up study, and admitting an out over sea level rise.
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Heh, the Holocene melts Continental glaciers but increases ice in Antarctica. Whoa, a brave new world for the alarmists.
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You never know …. but that might just be because Antarctica is a vast icy continent, is at an average height of 8000ft and sits over the south pole.
I should have said ‘other continental glaciers’.
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Ya but all those glaciers that are disappearing in the hymila’s are different
@ur momisugly Bob.. you can see the roughly billion or so people in the Indus Valley suffering because all of the glaciers melted years ago as predicted. (Sarc)
It’s the water table that’s the problem on that dispatched patch of Africa.
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Rishrac
3000 years ago or so you sarc may actually have happened so your skills are two fold am in awe.
Well damn, this climate doomology stuff is complicated. More snow, less snow, more rain, less rain; not to mention the disappearing heat. Good thing we have these “experts” figuring it all out.
They can’t find any global warming signal but,, by golly! there’s a darn good chance that it will show up by 2050. I now have the motivation to live to the ripe old age of ninety-six just so I can find out if they are right.
Let’s see here… my Dr. said if I gave up wine, women, and song I’d live to be 100. So if I quit singing, I should make 96 quite handily.
Well you may have a 97% chance !!
What a bunch of hooey. You cannot believe anything when you can’t get a good forecast about next weeks weather.
More hubris…
What if deposition increases over the Northern Hemisphere, too? Land based ice sheets form when deposition is greater than melting. That’s all a good ice sheet needs to get started, more deposition than melting. C’mon guys, your meta, big picture views of climate, ice, sea level cannot be very broad if your head is too far up your… er, model.
Ps. When will editors of journals start flatly rejecting articles filled with passive voice? The author’s use of the phrase “is though to have…” should have signaled automatic rejection of this paper. WHO thought that? WHY did they think that? Who disagreed with that? Where is the evidence for and against? Or, is it, as I suspect, just the AUTHOR who thinks that but isn’t willing to say so, outright?
Automatic rejection… it’s the only way. Don’t be shy. Reject it and quit allowing this kind of crap creep to sneak past.
If they did that, there would be no more “doomsday declarations.” What would the UN do then for its push to become the unelected but self believed needed world government?
What if deposition increases over the Northern Hemisphere, too? Land based ice sheets form when deposition is greater than melting……”
It wont.
Hasn’t happened at a time when the Earth’s orbit is unfavourable – as now (and for several thousand years yet).
@ur momisugly half precession now. Neither you nor anyone else knows when the Holocene ends, but we are more vulnerable now and for a few more thousand years than we have been in the recent past. If we get though this vulnerability, we’ll probably make it out to 20k years or so.
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I see we directly disagree about this point. My impression was that we are more vulnerable at half precession, so that we are now and for the near future more vulnerable than earlier in the Holocene.
I’ll await further discussion.
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Toneb, your comment wrongly assumes the most exaggerated case of my argument. I wasn’t predicting a new Laurentide ice sheet. Short of that level, nevertheless, a little warming might trigger more Northern Hemisphere snow deposition, just as has happened over the past 200 years (according to one paper I read) in certain coastal glaciers of the West Antarctic Ice Sheet (WAIS). It would only take some growth in the Greenland ice sheet, in NH alpine glaciers or Canadian or Siberian snow fields to sequester some H2O and thereby slow, stop or even reverse sea level rise.
I have a theory that the added weight of the accumulating ice causes the whole continent to sink into the mantle pushing out material in all directions. This displaces sea water causing the global sea level to rise.
If enough snow falls, the area around Antarctica will bulge out causing the Earth to become asymmetrical, start wobbling and all heck breaks loose. We are worried about frying when we should be worried about the stability of the Earth’s rotation.
As a matter of fact, I have written a computer model to illustrate it and will publish it in the Guardian (the only
ragpublication that has accepted it (so far). Maybe Anthony will pick it up afterwards.Wait a minute! Aren’t the ice sheets suppose to be melting? Doesn’t that offset the increased snow fall? And if the ice sheets aren’t melting, where is all that water coming from to rise sea levels ?
Apparently it’s ice sheets and glaciers from the rest of the continents, plus steric rise.
This was new to me that ice has been accumulating on Antarctica since the beginning of the Holocene.
Very interesting news.
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They got nuthin’ now but instability of the WAIS. Incoming!
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Like the Glacier Girls sisters in Greenland, thousands of pieces of equipment were buried hundreds of feet deep in Antarctic global warming ice long before CO2 became Karl Quixote’s windmill.
Notice the word “mitigating” in the following taken from the article?
“Increased snowfall over Antarctica is the sole process connected to global warming that is thought to have a significant mitigating effect on global sea level rise,”
Wait a minute! Aren’t the ice sheets suppose to be melting?
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At both poles…if they are right, ice in increase at both poles too
WR: The upper air above Antarctica receives input from the surrounding low pressure area’s. That air has a much higher water content than the average air at Antarctica and must have an influence on snowfall. Click on the images to read the local differences:
Actual images by Nullschool
Low pressure area’s: https://earth.nullschool.net/#current/wind/surface/level/overlay=mean_sea_level_pressure/orthographic=0.77,-89.43,587/loc=45.111,-61.302
Winds at 500 hPa (on the average around 5000 m., at Antarctica lower) :
https://earth.nullschool.net/#current/wind/isobaric/500hPa/orthographic=0.29,-88.33,750/loc=35.989,-38.426
Total precipitable water:
https://earth.nullschool.net/#current/wind/isobaric/500hPa/orthographic=0.29,-88.33,750/loc=35.989,-38.426
Increased temperature differences between the continuing-cold Antarctic and the rising temperatures more to the north result in a higher temperature gradient, which results in stronger winds. Stronger winds at the surface enhance enormously evaporation – and so the total water content of the air column and the transported air. This could / will increase snowfall at Antarctica.
It must be able to measure (!) this process.
A model prediction?
Thanks for the reality check. I’ll settle down now.
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” … natural climate variability, which comes from random, chaotic variations in the polar weather ”
Revealing that ‘natural climate’ is seen as random means that it cannot be modeled. Quite an admission.
Qualified with ‘polar’. Nonetheless, they don’t look back anymore; they can hear ravaging nature closing in.
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And no, we won’t kill them; ultimately the world will feel sorry for these poor trapped bastards, er scientists, caught in an Extraordinary Popular Delusion, almost as helpless as are we.
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Most natural climate variability is neither random or chaotic, but changes in cycles on multiple time scales. They are just admitting that they don’t know how it changes and assumes the natural variability will remain constant. They found that all those models with assumed inputs (fudge factors) produced values that were lost in the natural variability.. With natural variabily always changing, why should they expect the assumed “forcings” in the models to become statistically significant factors in the future? They need to model the natural variability without any assumed anthropogenic “forcing”..
To say that any of this will happen is anti-scientific drivel. The work is based on consensus forecasting of computer models, it is not based on any data worth talking about.
The hypothesis being posited is two fold:
1. Global warming will continue in a measurable and significant way up to 2050.
2. As a result of this global warming, precipitation over Antarctica will increase.
3. Because of this increased precipitation, some of the volume of oceanic water will be returned to solid phase as snow/ice in Antarctica.
4. Overall, the hypothesised rise in sea level due to the hypothesised global warming will be ameliorated somewhat, if thy hypothesised increase in Antarctic precipitation comes to pass.
Would you agree that on that basis, this is not NEWS, nor is it science.
It is scientific hypothesising, which must wait 34 years before being able to refute it or not.
“reduce the amount of global sea level rise by 51 to 79 millimeters,”
Just loving the accuracy, why not just say between 50 & 80mm? Models!!!!!
Frankly, they have no more precision than saying ‘some’.
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Because odd numbers are more believable.
See for example:
http://www.startupsafter50.com/marketing/magic-power-odd-numbers/
https://en.wikipedia.org/wiki/Psychological_pricing
It’s psychology at work.
Even more powerful psychology, faked precision gives the impression of increased accuracy to the untutored, which is most people about this issue. Little lies upon little lies.
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