New link between greenhouse gasses and sea level rise

Date:
April 6, 2022
Source:
British Antarctic Survey
Summary:
Researchers have used advanced ocean modelling techniques to
reveal how greenhouse gas emissions contribute to warmer oceans
and resulting melting of the West Antarctic Ice Sheet.



FULL STORY ==========================================================================
A new study provides the first evidence that rising greenhouse
gases have a long-term warming effect on the Amundsen Sea in West
Antarctica. Scientists from British Antarctic Survey (BAS) say that while others have proposed this link, no one has been able to demonstrate it.


==========================================================================
Ice loss from the West Antarctic Ice Sheet in the Amundsen Sea is one
of the fastest growing and most concerning contributions to global
sea level rise. If the West Antarctic Ice Sheet were to melt, global
sea levels could rise by up to three metres. The patterns of ice loss
suggest that the ocean may have been warming in the Amundsen Sea over
the past one hundred years, but scientific observations of the region
only began in 1994.

In the study -- published in the journal Geophysical Research Letters -- oceanographers used advanced computer modelling to simulate the response
of the ocean to a range of possible changes in the atmosphere between 1920-2013.

The simulations show the Amundsen Sea generally became warmer over
the century.

This warming corresponds with simulated trends in wind patterns in
the region which increase temperatures by driving warm water currents
towards and beneath the ice. Rising greenhouse gases are known to make
these wind patterns more likely, and so the trend in winds is thought
to be caused in part by human activity.

This study supports theories that ocean temperatures in the Amundsen Sea
have been rising since before records began. It also provides the missing
link between ocean warming and wind trends which are known to be partly
driven by greenhouse gasses. Ocean temperatures around the West Antarctic
Ice Sheet will probably continue to rise if greenhouse gas emissions
increase, with consequences for ice melt and global sea levels. These
findings suggest, however, that this trend could be curbed if emissions
are sufficiently reduced and wind patterns in the region are stabilised.

Dr Kaitlin Naughten, ocean-ice modeller at BAS and lead author of this
study, says, "Our simulations show how the Amundsen Sea responds to
long-term trends in the atmosphere, specifically the Southern Hemisphere westerly winds. This raises concerns for the future because we know
these winds are affected by greenhouse gases. However, it should also
give us hope, because it shows that sea level rise is not out of our
control." Professor Paul Holland, ocean and ice scientist at BAS and
a co-author of the study, says, "Changes in the Southern Hemisphere
westerly winds are a well-established climate response to the effect of greenhouse-gasses. However, the Amundsen Sea is also subject to very
strong natural climate variability. The simulations suggest that both
natural and anthropogenic changes are responsible for the ocean-driven
ice loss from the West Antarctic Ice Sheet."

========================================================================== Story Source: Materials provided by British_Antarctic_Survey. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Kaitlin A. Naughten, Paul R. Holland, Pierre Dutrieux, Satoshi
Kimura,
David T. Bett, Adrian Jenkins. Simulated Twentieth‐Century
Ocean Warming in the Amundsen Sea, West Antarctica. Geophysical
Research Letters, 2022; 49 (5) DOI: 10.1029/2021GL094566 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220406101737.htm

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