Skip to content

Ocean warming primary cause of Antarctic Peninsula glacier retreat

August 21, 2016
tags:

By Paul Homewood 

 

h/t Nordisch-geo-climber

 

image

http://www.swansea.ac.uk/media-centre/latest-research/oceanwarmingprimarycauseofantarcticpeninsulaglacierretreat.php

 

A new joint study from the British Antarctic Survey and Swansea University has found that it is ocean warming, and not atmospheric temperatures, which has been responsible for glacier retreat on the Antarctic Peninsula.

Swansea University issued this press release last month:

 

 

A new study has found for the first time that ocean warming is the primary cause of retreat of glaciers on the 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.

 

 British Antarctic Survey logo smaller

 

The study, published in the US Journal Science 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.

 

Antarctic glacier retreating 1

“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.”

 

Antarctic glacier retreating 2

 

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:

 

Antarctic glacier retreating 3

 

“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.

 

Antarctic glacier retreating 4

 

“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.”

http://www.swansea.ac.uk/media-centre/latest-research/oceanwarmingprimarycauseofantarcticpeninsulaglacierretreat.php

 

These findings are significant because they show that greenhouse gases are not the cause of glacier retreat there. There is no evidence that GHGs can have any measurable effect on ocean temperatures, nor on such a localised level. There is certainly no evidence that they do at depths of 100m and below.

Maybe we are seeing the result of changes in ocean currents or volcanic activity. What is now needed is more research to determine the real cause.

13 Comments leave one →
  1. sensferguson permalink
    August 21, 2016 4:03 pm

    There has been a fair amount of literature referring to the volcanic activity under the west antarctic peninsula – which will presumably heat the ocean therefore qed melting glaciers!

    • Sceptical Sam permalink
      August 22, 2016 9:35 am

      Yes. And, wouldn’t it be nice if these so-called scientists looked at some longitudinal data on localised changes in temperature of the Earth’s crust in their study area.

      Or is that too much to expect?

      • August 23, 2016 12:53 pm

        I wondered about that myself as I’ve seen articles on the active volcano under that west side. That should be a big, glaring issue right in front of their faces. An article in the Jan. 22, 2008 issue of “Science Daily” discussed the under-ice eruption of a volcano on the West Antarctic Ice Sheet. Data was provided for the article by British Antarctic Survey.

  2. A C Osborn permalink
    August 21, 2016 4:41 pm

    Just take a look on NuScool’s Earth for the Temperatures in the Antarctic and the seas around it. It hardly reached any kind of melting temperatures in the summer and is currently showing -57 in land and from -5 to -30 for the Sea surface around the coast.

  3. August 21, 2016 6:15 pm

    ‘There is no evidence that GHGs can have any measurable effect on ocean temperatures, nor on such a localised level. There is certainly no evidence that they do at depths of 100m and below.’

    Well, there won’t be any such evidence because longwave radiation can’t penetrate water. This is a well-known science ‘fact’ – anyone remember those😉

    • Get Real permalink
      August 21, 2016 7:50 pm

      Wash your mouth out with soap and go stand in the corner. “Science fact” indeed!!

  4. August 21, 2016 6:30 pm

    Perhaps we are looking at one of many natural feedback mechanisms to deal with warming. The ice melts in one spot to cool the ocean and at the same time more snow is deposited further inland. The net addition of water to the ocean may be zero or negative but heat has been removed from the ocean and transferred to the very cold atmosphere over the land.

  5. CheshireRed permalink
    August 21, 2016 10:03 pm

    O/T but AEP is at it again re CCS. Can you ask him how he thinks the UK will steal a march on the world using a system that does not yet exist anywhere on planet earth? (While you’re at it could you ask AEP if he’s living in a parallel universe? Ta. :-()

  6. ghostwhowalksnz permalink
    August 21, 2016 10:05 pm

    Then there was the recent NASA study
    “NASA Study: Mass Gains of Antarctic Ice Sheet Greater than Losses”
    That was looking at the whole continent where the vast Antarctic plateau is gaining ice
    http://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses

  7. johnmarshall permalink
    August 22, 2016 10:55 am

    How about geothermal heat? The Antarctic Peninsular is fairly volcanic.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: