While the wailers over at Media Matters bemoan claims of “distortion” over the recent NASA press release about Antarctica gaining ice mass due to increased snowfall over the last 10,000 years,…
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.
…this new study jointly announced by the AGU and the BAS says that the gains in the 20th century for the West Antarctic are the “highest we have seen in the last 300 years”.
From the AMERICAN GEOPHYSICAL UNION and the BRITISH ANTARCTIC SURVEY
West Antarctic coastal snow accumulation rose 30 percent during 20th century, study finds
WASHINGTON, DC — Annual snow accumulation on West Antarctica’s coastal ice sheet increased dramatically during the 20th century, according to a new study published in the American Geophysical Union journal Geophysical Research Letters.
The research gives scientists new insight into Antarctica’s blanket of ice. Understanding how the ice sheet grows and shrinks over time enhances scientists’ understanding of the processes that impact global sea levels, according to the study’s authors.
The new study used ice cores to estimate annual snow accumulation from 1712 to 2010 along West Antarctica’s coast. Until 1899, annual snow accumulation remained steady, averaging 33 and 40 centimeters (13 and 16 inches) of water, or melted snow, each year at two locations.
Annual snow accumulation increased in the early 20th century, rising 30 percent between 1900 and 2010, according to the new study. The study’s authors found that in the last 30 years of the study, the ice sheet gained nearly 5 meters (16 feet) more water than it did during the first 30 years of the studied time period.
“Since the record is 300 years long, we can see that the amount of snow that has been accumulating in this region since the 1990s is the highest we have seen in the last 300 years. The 20th century increases look unusual,” said Elizabeth Thomas, a paleoclimatologist with the British Antarctic Survey in Cambridge, United Kingdom, and lead author of the new study.
Thomas attributes the higher annual snow accumulation over the last 30 years in part to an intensification of a regional low pressure system and more storms in the region. The study’s authors said these storms could increase with climate change, possibly leading to further increases in snow accumulation.
Snow accumulation builds up the ice sheet, but the extra flakes have not acted as a life raft for West Antarctica’s ice sheet, which previous research has found is rapidly thinning as the climate warms, Thomas said.
The size of the ice sheet depends on how much new snow accumulates and how much of the existing ice melts, she said. Knowledge about how much new snow is laid down in West Antarctica each year could help scientists more accurately predict how the region’s coastal ice sheet could be affected by climate change and its contribution to sea level rise, Thomas said.
“In this region, the same [storms] that have driven increased snowfall inland have brought warmer ocean currents into contact with West Antarctic’s ice shelves, resulting in rapid thinning,” said Thomas. “Thus the increased snowfall we report here has not led to thickening of the ice sheet, but is in fact another symptom of the changes that are driving contemporary ice sheet loss.”
Ice on West Antarctica’s coast
Earth has two ice sheets – one in the Arctic, covering Greenland, and one sitting on Antarctica. Ice sheets start their lives as snowflakes. When snowfall builds up year after year, the weight of the snow compresses the bottom layers into ice, creating an ice sheet.
Scientists can calculate snow accumulation from satellite data, but satellite records have only existed since 1979. That’s too short a time period to determine whether any changes in snowfall are the result of natural variation or shifts in the climate, Thomas said.
“We need to understand whether we are losing ice, at what rate, and what is causing it,” she said.
For the new study, researchers collected two ice cores from Ellsworth Land, the strip of land that connects the Antarctic Peninsula to the rest of the continent. The ice cores contain layer upon layer of ice – the remnants of yearly snowfall. By measuring the thickness of the ice laid down each year, the researchers estimated annual snow accumulation for the past 300 years.
The recent heavy snow accrual appears to be part of a gradual, long-term rise in annual snow accumulation that started in the early 1900s and accelerated in the 1980s, the study found. The study’s authors found that starting in the early 20th century an additional 1.5 centimeters (0.6 inches) of water, or melted snow, was added to the ice sheet each decade. From 2001 to 2010, the amount of water added to the ice sheet each year was 15 centimeters (6 inches) greater than it was before 1900, according to the study’s authors.
A stormy sea
The study’s authors attribute the rise in snow accumulation in part to increased regional storm activity. The Amundsen Sea, which bounds Ellsworth Land to the west, is prone to storms and low pressure systems that often sit over the region, Thomas said.
Meteorological data, which only date back 35 years, show the low pressure system has strengthened during that time, leading to more storms swirling around the Amundsen Sea and potentially greater snow accumulation, according to the paper. The uptick in snow accumulation since the 1920s may suggest an even longer trend of increasing storms, Thomas said.
Scientists have not pinpointed the reason for the strengthening of the low pressure system in the Amundsen Sea, but the number and intensity of storms in the region could continue to increase throughout the 21st century as a consequence of greenhouse gas warming, Thomas said. In a warmer climate, air travelling south from the mid-latitudes and tropics can hold more water, leading to more snowfall, Thomas said.
The paper draws a convincing connection between the intensification of the Amundsen Sea low-pressure system and increasing snow accumulation, said David Bromwich, a polar weather and climate scientist with the Byrd Polar and Climate Research Center at Ohio State University in Columbus, who was not an author on the new paper. The low-pressure system is likely one of several factors contributing to the increase in snowfall, he said.
Antarctic climate results from a complex mix of oceanic and atmospheric circulation patterns, so there could also be other components affecting the amount of snow accumulation in the region, Bromwich said. As the paper suggests, one could be the evaporation of surface waters that have become exposed because of sea ice loss in the region, he added.
View the press release on the British Antarctic Survey website.
###
Source: http://news.agu.org/press-release/west-antarctic-coastal-snow-accumulation-rose-30-percent-during-20th-century-new-study-finds/
The American Geophysical Union is dedicated to advancing the Earth and space sciences for the benefit of humanity through its scholarly publications, conferences, and outreach programs. AGU is a not-for-profit, professional, scientific organization representing more than 60,000 members in 139 countries. Join the conversation on Facebook, Twitter, YouTube, and our other social media channels.
Title: “Twentieth century increase in snowfall in coastal West Antarctica”
Authors: E.R. Thomas, J.S. Hosking, R.R. Tuckwell, R.A. Warren, and E.C. Ludlow: British Antarctic Survey, Madingley Road, Cambridge CB3 0ET, UKE.
Link:http://onlinelibrary.wiley.com/doi/10.1002/2015GL065750/abstract?campaign=wlytk-41855.5282060185
Note: about 5 minutes after publication, this article was updated to remove an email address of one of the authors to prevent spam harvesting and a link to the AGU website added. The title was corrected to add the word “snowfall”,
I read that Media Matters piece yesterday.
It can basically be summarized/satirized as follows:
A scientific study has been released strongly suggesting that P = false.
A hypothesis H predicts the outcome P = true.
The author of this study has suggests that the result is likely to be embraced by the group of people who like to continue to examine whether the hypothesis H is validated by the available evidence – or at least that other hypotheses should be given some serious consideration.
Or that some attempt should be made to disprove the alternative hypotheses.
Or that some attempt should be made to critically assess the repeated failure of specific predictions generated by the hypothesis H.
Media Matters and the Author simply dismiss such people by calling them d*n**rs.
Media Matters and the Author don’t seem to understand how science really works.
Media Matters would doubtlessly like to re-focus the attention of the global media audience on speculation, alarmism and popular voodoo science.
Hi NASA !! Welcome to the real world !
Let me see if I have this right. In the last week we have been informed that both East and West Antarctica are gaining ice except near the one coast that sits on top of measured geothermal heat. We have found out that the Greenland ice sheet has not been losing as much ice as previously claimed. We’ve seen record sea ice levels around Antarctica for the past 3 years as well as increases in Arctic sea ice volume over the same period of time. All of this has happened when CO2 levels have been at all time high levels.
This new data tells us that GRACE is likely not a very good source of information which also means some of the sea level data may be wrong. It also calls into question the GIA adjustment to sea level.
I’m sure all of this will be presented at COP21. 😉
“I’m sure all of this will be presented at COP21.”
Only if that unusual delegate from Burma pops up again!
I’m confused.
On the one hand, it seems that Antarctica now has the greatest area of sea on record.
On the other “In this region, the same [storms] that have driven increased snowfall inland have brought warmer ocean currents into contact with West Antarctic’s ice shelves, resulting in rapid thinning,”
If warmer currents are in contact with the ice shelves, wouldn’t all that sea ice melt?
Richard M’s points:
are further buttressed by the fact that RSS “South Polar” temperature has been in a slight and steady decline over the entire satellite record.
We should enjoy Antarctic snow while we can. It will soon be rare, a thing of the past, the Antarctic reduced to a sloppy spring-thaw puddle.
Given that temperatures in Antarctica are so far below freezing, it’s hard to see how increased storminess wouldn’t increase the ice sheet. It seems pretty certain that warming will increase precipitation. Do even the most ardent warmists believe that it’s going to start raining down there? Obviously it’s going to snow more and the only mechanism to melt this snow is by glacial calving. And given that sea temperature trends are flat I don’t see any increased calving.
In general, this bolsters the basis of my disagreement with alarmists who caterwaul about glacial recession with the unfounded claim that there will be a lot less water flowing at the bottom of the hill when the glacier is gone. It does not seem be the case for non-glacially fed rivers –
https://books.google.com/books?id=bx7uuYmAkaMC&pg=PA36&lpg=PA36&dq=higher+rivers+1000+years+ago&source=bl&ots=aN2Xt2U1Hg&sig=TCfzesm2jMOmVb7Add4O5QmziYs&hl=en&sa=X&ved=0CDMQ6AEwA2oVChMIibbMhsj5yAIVRRo-Ch1xNwDr#v=onepage&q=higher%20rivers%201000%20years%20ago&f=false
(White Nile) “… fluctuated at higher levels until 3100 years ago then remained fairly low until 1000 years ago.”
So why suspect a different outcome for glacially fed ones? Gee I wonder what was going on ~1000 years ago? How alarming to know that there was more precipitation to feed Lake Victoria in warmer times; well, alarming to the alarmists that is.
Well this appears to settle why the West ice flows calving is increasing. More volume of snow, leading to more ice, leading to more pressure, leading to increase of flow towards sea.
Simple mechanics.
I object to this kind of statement:
“That’s too short a time period to determine whether any changes in snowfall are the result of natural variation or shifts in the climate, Thomas said.”
It does not allow for an interpretation that shifts in climate may be natural. We know there have been significant naturally occurring changes in climate but this kind of statement warps the conversation.
The true lesson of climate science is that it is astounding what we don’t know.
I can imagine that some guy a few thousand years ago suddenly figured out that glaciers moved. I’m sure he freaked out, thinking that something that had been going on for millions of years had just recently started.
Our records of direct measurements only go back a few decades. We get a rough idea of what things might have been like a million or a thousand years ago by interpreting evidence that was left behind. All this is great except for when someone tries to tell us that we can pinpoint the temperature of the Earth a thousand or even a hundred years ago to a tenth of a degree. At that point, the reasonable man should raise his eyebrows and wonder just exactly what these folks are selling.
Didn’t they use to call stuff like that ” Snake Oil Medicine ” ???
True Dat
The true lesson of climate science is that it is astounding what we don’t know.
And what we had never been able to measure before now (the last few decades).
I am thinking that there is a truce to be negotiated with climate scientists. We can agree to go ahead and fund legitimate efforts to understand our climate and in return they can agree to act like scientists. Maybe if we remove the incentive to run around with their hair on fire in order to get funding this stuff will calm down some.
“Scientists have not pinpointed the reason for the strengthening of the low pressure system in the Amundsen Sea, but the number and intensity of storms in the region could continue to increase throughout the 21st century as a consequence of greenhouse gas warming, Thomas said. In a warmer climate, air travelling south from the mid-latitudes and tropics can hold more water, leading to more snowfall, Thomas said”
As a consequence of greenhouse warming? LOL poor Elizabeth Thomas. The increased frequency of deeper depressions is linked to the expulsion of stronger, higher pressure MPHs from Antarctica, reaching further towards the equator as pressure values – such as on Easter Island, or on Mauritius Island- show a significant rise since the 1970s. Thus it is not warming that creates these storms but a renewed dynamics, stronger catabatic winds, sign of a slight cooling. Humid air from tropical areas reached by these MPHs is advected and precipitated along the reliefs, hence increased snowfalls. (Leroux, dynamic analysis of weather and climate, Springer Praxis 2010)
Check how lower tropospheric circulation works!
http://www.dwd.de/DE/leistungen/wv1!_satellit_goes13/satellit_goes13.html?nn=16102
http://www.bom.gov.au/fwo/IDY65100.pdf
The carbon scolds don’t care about the data, they care about the narrative.
It doesn’t matter that peat fires in Indonesia are producing more CO2 than the entire EU combined.
It doesn’t matter that NOAA’s own data show that mean and median sea level is rising by only 1.1 to 1.2 mm / year worldwide.
http://tidesandcurrents.noaa.gov/sltrends/MSL_global_trendtable.html
They have convinced the credulous media that your SUV is going to flood Miami, NYC, and DC any day now, and pushing that narrative is all that matters.
I’m pretty sure I’m not the first one to think of this, but shouldn’t “we” as a general rule, assume that IF WAIS glaciers are moving faster, that the number one cause should be presumed to be a heavier push from above, i.e. more deposition? Call me crazy, but that’s what I do.
dbstealy asked me to use percentages instead of Gt a while ago, so I had a quick look. The Antarctic ice sheet weighs something like 34 million Gt. The order of gain or loss is around 100Gt annually, which is 0.0003% of the total weight of the icesheet. It does not seem likely that this level of change will greatly affect the speed of the glaciers in the short term.
Heh. I’ve colonized seaice’s mind. He’s fixated on me. ☺
He’ll deny it. But is there any doubt?
dbstealey – sorry, I missed out that final “e”. The percentage thing was a good idea.
Surely such contradictions need to be sorted out by Professor Turney and his Ship of Fools in their next Antarctic Vacation.
Discovery takes this news and appears to blow it totally out of proportion claiming Antarctic Melting Irreversible In 60 Years !!
http://news.discovery.com/earth/global-warming/snow-mounts-in-antarctica-but-ice-loss-continues-151105.htm?utm_source=facebook.com&utm_medium=social&utm_campaign=Discovery
Go figure…..
Now that NASA has finally admitted that Antarctic land ice has been growing at a weighted-average of 100 billion tons/yr instead of decreasing at 100 billion tons/yr, Sea Rise Level “adjustments” need to be lowered to account for net difference of 200 billion tons/yr of water that was assumed to have gone into the oceans….
That’s a miscalculation of 200 billion/yr x 23 years= 4.6 TRILLION tons of water that’s NOT where it was assumed to be….
The SLR modelers also assumed that steric rebound from lost Antarctic land ice would accelerate SLR…. They now have to recalibrate their steric rebound assumptions by 4.5 TRILLION tons…
Obviously these adjustments should be made, however, how many people think NASA/NOAA will actually make these necessary SLR adjustments….
What a joke.
technically spoken that’s not so hard: 4.6 trillion tons that cause pressure on antarctica and thus the seafloors around it get uplifted = sea level rise.
same for the WAIS: more snow can simply also increase a glacier’s speed in a constant temperature regime. however also there the weight should increase. (note the recent found geothermal activity can cause a loss). combine both and that’s how antarctica can even add more to the sea level rise then previously thought. the addition of weight is at the right spot for it: the resulting uplift around antarctica’s “sinking” is in the less land covered area of the earth. so it is all seafloor that would then be uplifted.
that’s just a “reverse logic” of the isostatic rebound from the ice age occuring in the northern hemisphere. it’s far from proven, but i would suspect the seabed is rising around antarctica if that continent is gaining mass and that this isostatic rise would perhaps even be the biggest contributor to the actual sea level rise we are observing.
but as said this is just a logical “guess” based on the scientific explenations of isostatic fluxes of the earth crust, however i am tempted to believe this guess might be closer to the truth then all their models which prove to have failed
Frederik– Actually, the isosteric rebound effect hypothesizes that decreasing land-ice would decrease pressure on the earth’s crust and cause a rebound of the earth’s crust, thereby increasing sea-level rise…
All the SLR computer models assumed Antarctic land ice was adding 100 billion tons of melt water to the oceans, AND that the subsequent isoteric rebound was further increasing SLR…
Now that these assumptions have been proven wrong, I just wonder if NASA/NOAA will correct these errors in their SLR models.
My guess is that they’ll just leave these errors in their SLR models and make a footnote stating,”(*based on GRACE satellite data)”…
What a joke.