A new study has found for the first time that ocean warming is the primary cause of retreat of glaciers on the western Antarctic Peninsula. The Peninsula is one of the largest current contributors to sea-level rise and this new finding will enable researchers to make better predictions of ice loss from this region.
The research, by scientists at Swansea University and British Antarctic Survey, is published in the journal Science today (Friday, July 15). The study reports that glaciers flowing to the coast on the western side of the Peninsula show a distinct spatial correlation with ocean temperature patterns, with those in the south retreating rapidly but those in the north showing little change. Some 90% of the 674 glaciers in this region have retreated since records began in the 1940s.
Dr Alison Cook, who led the work at Swansea University, says:
“Scientists know that ocean warming is affecting large glaciers elsewhere on the continent, but thought that atmospheric temperatures were the primary cause of all glacier changes on the Peninsula. We now know that’s not the case.
“The numerous glaciers on the Antarctic Peninsula give a key insight as to how environmental factors control ice behaviour on a wide scale. Almost all glaciers on the western side end in the sea, and we’ve been able to monitor changes in their ice fronts using images as far back as the 1940s. Glaciers here are extremely diverse and yet the changes in their frontal positions showed a strong regional pattern.
“We were keen to understand what was causing the differences, in particular why the glaciers in the north-west showed less retreat than those further South and why there was acceleration in retreat since the 1990s. The ocean temperature records have revealed the crucial link.”
The team studied ocean temperature measurements around the Peninsula stretching back several decades, alongside photography and satellite data of the 674 glaciers.
The north-south gradient of increasing glacier retreat was found to show a strong pattern with ocean temperatures, whereby water is cold in the north-west, and becomes progressively warmer at depths below 100m further south. Importantly, the warm water at mid-depths in the southerly region has been warming since as long ago as the 1990s, at the same time as the widespread acceleration in glacier retreat.
Co-author Professor Mike Meredith at British Antarctic Survey says:
“These new findings demonstrate for the first time that the ocean plays a major role in controlling the stability of glaciers on the western Antarctic Peninsula.
“Where mid-depth waters from the deep ocean intrude onto the continental shelf and spread towards the coast, they bring heat that causes the glaciers to break up and melt. These waters have become warmer and moved to shallower depths in recent decades, causing glacier retreat to accelerate.”
Co-author Professor Tavi Murray, who leads the Glaciology Research Group at Swansea University, says:
“The glaciers on the Antarctic Peninsula are changing rapidly – almost all of the Peninsula’s glaciers have retreated since the 1940s. We have known the region is a climate warming hotspot for a while, but we couldn’t explain what was causing the pattern of glacier change.
“This new study shows that a warmer ocean is the key to understanding the behaviour of glaciers on the Antarctic Peninsula. Currently the Peninsula makes one of the largest contributions to sea-level rise, which means understanding this link will improve predications of sea-level rise.”
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http://www.ospo.noaa.gov/data/sst/anomaly/2016/anomnight.7.14.2016.gif
What warming and the Southern Ocean has had temperatures below normal for many years just not presently so this is another BS article.
Which all raises the question, what is causing the ocean, esp at mid-depth, to warm? It certainly cannot be CO2, as, even if there was a mechanism for it to cause it, the heat capacity of the ocean is so great as to make any temperature difference so small as to be unmeasurable.
So, are we seeing warm waters being transported from elsewhere?
Paul,
Your post of January shows how feeble the CAGW ocean warming argument is
https://notalotofpeopleknowthat.wordpress.com/2016/01/21/can-co2-warm-the-oceans/
Oh you are not gullible enough to believe CO2 already warmed significantly the deep waters in question? D*nier. /sarc
But this is of course climate change, not warming. Stronger winds cause stronger stream of water to melt more ice. CC explains everything. /church of cc
Yep. Net discharge. The only way we can rise out of a stadial glacial period is if the oceans switch from net recharge to net discharge of stored heat. No other source of heat has been measured that can account for that sudden switch to a rapid millennial length rise to a warm interstadial period (with the assumption that we can rule out CO2 because it follows heat, not causes heat). Once at that peak it appears that we stay there for a relatively short period of time, bouncing between small discharge/recharge ocean conditions prior to the oceans switching to millennial length slow net recharging mode, leading us back down in jagged steps to another stadial glacial period. In my mind experiment, the vast ocean volume, slowly storing heat and then rapidly sending it back out, is a plausible mechanism, using current thermodynamic modeling of such a volume of water in slow oscillation between recharge and discharge, with orbital solar insolation assisting that swing.
From the article: “We have known the region is a climate warming hotspot for a while, but we couldn’t explain what was causing the pattern of glacier change.”
As far as I’m concerned, you *still* haven’t explained it. You say it is because of warmer water, but you don’t say why the water is warmer.
If the heat is originating in the deeper levels, volcanic activity might be involved. But you didn’t say “yeah” or “nay” on that point.
There’s an interesting book published in 1950 by Thomas R Henry, a journalist-writer who toured with the 1930-33 Admiral Byrd expedition. They noted the geothermal and volcanic aspects affecting areas of melt, as well as ocean currents affecting certain regions. The book is called The White Continent. Those explorers had some true grit!
My late father used to talk about an activity he was involved in during the early 1940s which had the effect of massively increasing aerosols and dust and smoke and stuff. Fortunately, although several times wounded, he was not killed.
“This new study shows that a warmer ocean is the key to understanding the behaviour of glaciers on the Antarctic Peninsula. Currently the Peninsula makes one of the largest contributions to sea-level rise, which means understanding this link will improve predications of sea-level rise.”
The Antarctic Peninsula is so small relative to the Antarctic that the changes at the peninsula does not mean anything and can not be used for any predictions.
In fact it is the whole continent (or whatever it is called) that influences the sea level. Look at a map.