New research shows projected changes in the winds circling the Antarctic may accelerate global sea level rise significantly more than previously estimated.
Changes to Antarctic winds have already been linked to southern Australia’s drying climate but now it appears they may also have a profound impact on warming ocean temperatures under the ice shelves along the coastline of West and East Antarctic.
“When we included projected Antarctic wind shifts in a detailed global ocean model, we found water up to 4°C warmer than current temperatures rose up to meet the base of the Antarctic ice shelves,” said lead author Dr Paul Spence from the ARC Centre of Excellence for Climate System Science (ARCCSS).
“The sub-surface warming revealed in this research is on average twice as large as previously estimated with almost all of coastal Antarctica affected. This relatively warm water provides a huge reservoir of melt potential right near the grounding lines of ice shelves around Antarctica. It could lead to a massive increase in the rate of ice sheet melt, with direct consequences for global sea level rise.”
Prior to this research by Dr Spence and colleagues from Australian National University and the University of New South Wales, most sea level rise studies focused on the rate of ice shelf melting due to the general warming of the ocean over large areas.
Using super computers at Australia’s National Computational Infrastructure (NCI) Facility the researchers were able to examine the impacts of changing winds on currents down to 700m around the coastline in greater detail than ever before.
Previous global models did not adequately capture these currents and the structure of water temperatures at these depths. Unexpectedly, this more detailed approach suggests changes in Antarctic coastal winds due to climate change and their impact on coastal currents could be even more important on melting of the ice shelves than the broader warming of the ocean.
“When we first saw the results it was quite a shock. It was one of the few cases where I hoped the science was wrong,” Dr Spence said.
“But the processes at play are quite simple, and well-resolved by the ocean model, so this has important implications for climate and sea-level projections. What is particularly concerning is how easy it is for climate change to increase the water temperatures beside Antarctic ice sheets.”
The research may help to explain a number of sudden and unexplained increases in global sea levels that occurred in the geological past.
“It is very plausible that the mechanism revealed by this research will push parts of the West Antarctic Ice Sheet beyond a point of no return,” said Dr Axel Timmerman, Prof of Oceanography at University of Hawaii and an IPCC lead author who has seen the paper.
“This work suggests the Antarctic ice sheets may be less stable to future climate change than previously assumed.”
Recent estimates suggest the West Antarctic Ice Sheet alone could contribute 3.3 metres to long-term global sea level rise.
With both West and East Antarctica affected by the change in currents, in the future abrupt rises in sea level become more likely.
According to another of the paper’s authors, Dr Nicolas Jourdain from ARCCSS, the mechanism that leads to rapid melting may be having an impact on the Western Antarctic right now. Dr Jourdain said it may help explain why the melt rate of some of the glaciers in that region are accelerating more than scientists expected.
“Our research indicates that as global warming continues, parts of East Antarctica will also be affected by these wind-induced changes in ocean currents and temperatures,” Dr Jourdain said.
“Dramatic rises in sea level are almost inevitable if we continue to emit greenhouse gases at the current rate.”
Abstract
The southern hemisphere westerly winds have been strengthening and shifting poleward since the 1950s. This wind trend is projected to persist under continued anthropogenic forcing, but the impact of the changing winds on Antarctic coastal heat distribution remains poorly understood. Here we show that a poleward wind shift at the latitudes of the Antarctic Peninsula can produce an intense warming of subsurface coastal waters that exceeds 2 °C at 200-700 m depth. The model simulated warming results from a rapid advective heat flux induced by weakened near-shore Ekman pumping, and is associated with weakened coastal currents. This analysis shows that anthropogenically induced wind changes can dramatically increase the temperature of ocean water at ice sheet grounding lines and at the base of floating ice shelves around Antarctica, with potentially significant ramifications for global sea level rise.
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So what about claims, that Antarctica Ice Sheet doesn`t melt ?
http://wattsupwiththat.com/2014/07/06/lying-with-statistics-the-national-climate-assessment-falsely-hypes-ice-loss-in-greenland-and-antarctica/
It can’t possibly be models the whole way down.
There must be a turtle down there somewhere to take the strain down at the bottom, thats if it hasn’t drowned in the modeled BS.
Hmm, “may” and “can” … But not “are”
“When we included projected Antarctic wind shifts in a detailed global ocean MODEL, we found water up to 4°C warmer than current temperatures rose up to meet the base of the Antarctic ice shelves,”
All based on a Model..lol
When are they going to realize that models are what they eat.(selected data put into them)
Anthony, When is some one going to do a Peer Rewired study on how the models are a Complete Failure.
And the continued growth of Antarctic sea ice is explained how?
““When we first saw the results it was quite a shock. It was one of the few cases where I hoped the science was wrong,” Dr Spence said.”
Seriously?
bernie1815 – where did you find, that Ice sheet is growing ??
” “When we first saw the results it was quite a shock. It was one of the few cases where I hoped the science was wrong,” Dr Spence said. ”
Says a lot, doesn’t it? Science = computer modeling of “what we think.” Want to bet whether there is actually any physical data that he can present that will support the model’s output? Funny how changes in the winds haen’t seemed to slow down the ice buildup, but when you can model the currents and how they are affected by the wind up to 700m below the ice, you have moved closer to “godhood” than I could imagine, so I will bow down to his god like” wisdom.
We have invented a range of probabilities. The lowest on the scale are the scariest and meant to draw the most media attention.
Nomination for the “I am Scared of Climate Change” theme song: (enjoy)
We must see that the ice in the south breaking records not only in winter, but in summer. This means only one thing: the temperature drop atmosphere.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.antarctic.png
http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_ANOM_JFM_SH_2014.gif
These winds have been blowing like this for the past 33.6 million years when Antarctica became fully glaciated over and the Antarctic Circumpolar Current started up.
This occured when CO2 was 1,400 ppm.
Sailing ships from the late-1500s onwards (when CO2 was 275 ppm) have almost never been able to make it through the Drake Passage (between South America and Antarctica) because of these winds.
Climate models do not trump real history.
Previous global models did not adequately capture these currents and the structure of water temperatures at these depths. … “But the processes at play are quite simple, and well-resolved by the ocean model, so this has important implications for climate and sea-level projections.
==============
If the process is so simple, why did previous models “not adequately capture”?
Could it be that simplicity is more a state of mind, rather than a property of ocean currents. Is it possible that the researchers have underestimated the complexity of the physical process they are seeking to model?
Maybe when…..maybe if…..could and might. Nice precise scientific terms!!??
So:- “Previous global models did not adequately capture these currents and the structure of water temperatures at these depths. Unexpectedly, this more detailed approach suggests changes in Antarctic coastal winds due to climate change and their impact on coastal currents could be even more important on melting of the ice shelves than the broader warming of the ocean.”
Also, these previous models didn’t model the increase in antarctic ice, although the author seems to overlook that bit. I recommend that he doesn’t charter a ship and go there as he will only get stuck in the ice that shouldn’t be there according to his computer game.
model outputs translated as “truths” This is how they “smoke and mirror” the world. It’s all pure fantasy. In God we trust. All others bring data.
baart1980: Sea ice is not the same as ice sheet. Try this for monitoring Antarctic sea ice:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.anomaly.antarctic.png
“When we first saw the results it was quite a shock. It was one of the few cases where I hoped the science was wrong,” Dr Spence said.
========
How do you know it isn’t wrong? How was the model validated?
The simple fact is that the model cannot have been validated, because it is trying to predict the future, years in advance. However, ocean flows are turbulent and thus chaotic, and thus cannot be predicted beyond a few days in the future using current technology.
“Previous global models did not adequately capture these currents and the structure of water temperatures at these depths. Unexpectedly….”
The old unproved models were wrong, but you can trust our new unproved models.
Where the hell were these people trained? You would think real scientists in other hard science disciplines at those institutions would start to complain about the sullying of their institution’s reputation.
More ice melting from warmer water? Thank goodness for that, because warmer water means more snowfall, so without more melting all the water in the world would pile up on top of Antarctica.
“The research may help explain a number of sudden and unexplained increases in global sea levels that occurred in the geological past”
Does this mean that this is a natural mechanism not related to “man made global warming”, oh sorry ” man made climate change”?
It was one of the few cases where I hoped the science was wrong
=============
Wouldn’t it be more correct to say:
It was one of the few cases where I hoped the MODEL was wrong
The author is assuming that the model is a 100% correct representation of science. This is a physical impossibility. A computer model is at best a rough approximation of reality, that will quickly diverge from reality the longer it runs.
I was going to leave a comment, but ferdberple & Partrick B have captured the gist of what is wrong with this conjecture.
“The research may help explain a number of sudden and unexplained increases in global sea levels that occurred in the geological past”
================
strange how the increases that occurred in the past were natural, but those that will occur in the future must be man-made.
The models are performing brilliantly (as always)! It is the reality and observations that are corrupted and unreliable. We must learn to observe as the models leads.
A model is… what a model does. GK