Thwaites Glacier Antarctica

Antarctica sheet ice is rapidly melting

If you tuned in to international news at the turn of this year, you may have heard of the research ship, MV Akademik Shokalskiy being stranded in thick pack ice off the coast of Antarctica. Climate change deniers tried to use this event to incorrectly demonstrate why climate change was a farce.

While some people can not seem to grasp the difference between weather and climate change, or sea ice and ice sheets, new climate change research in Antarctica released in May 2014 by NASA, clearly shows that climate change is having a much broader and devastating effect on ice levels in Antarctica than previously discussed.

8 facts you should know about Antarctica

  1.  Average year long temperatures range from -10°C in summer to below -40°C in winter.
  2. Antarctica is the coldest place on Earth.
  3. Underneath the ice sheets in Antarctica is a huge land mass.
  4. 90% of all global ice is located in the Antarctic.
  5. Ice sheets in Antarctica account for 3/4 of global fresh water reserves.
  6. Antarctica does not have polar bears, it has penguins.
  7. Antarctica does not have any human indigenous populations.
  8. 50 Countries are party to the Antarctic Treaty that came into force on 23 June 1961.

Sea ice versus ice sheet

Sea Ice

In 2013, Antarctica recorded one the largest increases in sea ice than in any  other year.

Sea ice is frozen sea water which expands and decreases depending on the weather.

Sea ice in contrast to land ice does not affect the sea level. As sea ice is already floating on the sea, it creates an equilibrium with the sea level.

Melting Sea ice in the Artic

Climate change studies on the dramatic disappearance of sea ice in the Arctic have found correlations between:

Likewise, studies on the increase of sea ice in Antarctica have also found links to climate change.

 “…Antarctic sea ice drift caused by changing winds are responsible for observed increases in Antarctic sea ice cover in the past two decades.” [ NASA study examines Antarctica sea ice increases

Antarctica Sea Ice
Ryder Bay near Rothera Research Station, Adelaide Island, Antarctica.

Antarctic Sea Ice

In 2013 the U.N. Intergovernmental Panel on Climate Change (IPCC) reported a small increasing trend in the amount of sea ice in the Antarctic of about 1.49 ± 0.18 % per decade.

Australia’s Antarctic division reports that while parts of Antarctica such as the Ross and Weddell seas have experienced small increases in sea ice in recent years, there is a loss of sea ice from other parts of the Antarctic such as the Bellingshausen sea.

Conclusions indicate overall growth of sea ice is marginal and caused by ozone and weather variations.

Future climate modelling predicts sea ice in the Antarctic will decrease by almost a third by 2100 as ocean temperatures continue to rise.

The ozone hole above Antarctica has also been cited as a reason for the variation in sea ice in the South. The ozone hole actually intensifies a perpetual vortex of winds that circle the South Pole.

Changes to atmospheric weather patterns  is another key contender for the increase in sea ice in some parts of the antarctic.

Ice Sheet

An ice sheet is ice formed by falling snow.

Ice Sheets
Globes showing Greenland and Antarctica’s Ice Sheets

 

There are only two major ice sheets in the world.  These are located in Greenland and Antarctica. Together they hold about 99% of the world’s fresh water. Antarctica contributes to about 75% of the world’s fresh water.

An ice sheet can flow over the sea. This is called ice flow and it occurs in multiple directions from the center of the ice sheet.

When an ice sheet hangs over the ocean it is called an ice shelf. The area where the ice sheet last touches land before going out over the sea is its grounded line.

Antarctica sheet ice

More recently (May 2014), NASA promoted new scientific evidence  showing glaciers in the Amundsen Sea sector of West Antarctica –

..”have passed the point of no return,”.. [Glaciologist and lead author Eric Rignot – Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith and Kohler glaciers, West Antarctica from 1992 to 2011. ]

Major points of the study include

  • enough ice to increase sea levels by 4 feet or 1.2 metres.
  • accelerated flow rates
  • grounding lines have retreated inland
  • bedrock topography (slopes down below sea level) will allow warmer sea water under the sheet ice and increase the rate at which it is melting


Bed topography of West Antarctica. Key: brown below sea level;  itself is colored yellow, and green areas are above sea level. Image credit: NASA/GSFC/SVS
West Antarctica topography. Key: brown –  below sea level;  yellow – sea level, green above sea level. Image credit: NASA/GSFC/SVS

IPCC sea level predictions do not account for  sheet ice melt in Antarctica

Conservative estimates suggest the total collapse of the West Antarctica sheet ice from Amundsen Sea sector could take a few centuries.

The U.N. Intergovernmental Panel on Climate Change (IPCC),  predict an increase of sea level by 2100  from just less than 1 foot to about 3 feet.

Most of these projections do not take into account the impact that ice loss from Antarctica will have on sea levels. This new scientific evidence on the sheet ice in West Antarctica suggests sea level rise projections should lean toward the higher end of these predictions.

 

Research ship, MV Akademik Shokalskiy

Predictably, after all passengers on the research ship MB Akademik Shokalskiy were rescued, the ship broke free as the sea ice naturally broke up and melted about two weeks after it became stuck.

Though climate change deniers have tried to claim the  event as an example against climate change, it really is an excellent example of how sea ice is impacted by the changing weather.

Perhaps with a broader understanding of the weather and climate in the Antarctic, ignorant claims of global cooling demonstrated in the comments of the video preview on YouTube below, can be avoided.

Instead focus can be given to the Antarctica sheet ice rapid melt and other climate change challenges in the Antarctic that appear to be irreversible and threaten our ecosystems and the living conditions of our future generations.

 

 

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