Reducing the melting of Greenland ice cap using solar geoengineering?


Date:
July 7, 2021
Source:
University of Liege
Summary:
Injecting sulphur into the stratosphere to reduce solar radiation
and stop the Greenland ice cap from melting: An interesting
scenario, but not without risks. Climatologists have looked into
the matter and have tested one of the scenarios put forward using
the MAR climate model. The results are mixed.



FULL STORY ========================================================================== Injecting sulphur into the stratosphere to reduce solar radiation and
stop the Greenland ice cap from melting. An interesting scenario, but
not without risks.

Climatologists from the University of Lie`ge have looked into the matter
and have tested one of the scenarios put forward using the MAR climate
model developed at the University of Lie`ge. The results are mixed and
have been published in the journal The Cryosphere.


==========================================================================
The Greenland ice sheet will lose mass at an accelerated rate throughout
the 21st century, with a direct link between anthropogenic greenhouse
gas emissions and the extent of Greenland's mass loss. To combat this phenomenon, and therefore global warming, it is essential to reduce our greenhouse gas emissions. Every day new ideas emerge to slow down global warming, such as the use of solar geoengineering, a climate intervention
that consists of artificially reducing solar radiation above the ice caps
and thus limiting the melting of the ice. How can this be done? The idea
is to inject sulphur into the stratosphere, a stable meteorological zone located between 8 and 15 km above sea level in the atmosphere," explains
Xavier Fettweis,climatologist and director of the Climatology Laboratory
at ULie`ge. The sulphur will then act as a sort of mirror that will
reflect part of the solar radiation back into space." An intervention
which therefore makes it possible to reduce the amount of sunshine on
earth, similar to what happens during volcanic eruptions. In 1991,
the eruption of Pinatubo (Philippines) injected millions of tonnes
of sulphur dioxide into the stratosphere, causing a drop in global
temperatures of around 0.5DEGC. This observation led to the development
of solar geoengineering scenarios. Are these scenarios really reliable
and risk-free? This is what the ULie`ge climatologists wanted to test.

We used a plausible scenario of solar geoengineering (G6solar) that
would reduce global warming by a factor of 2 on a global scale compared
with the most pessimistic scenario in which nothing would be done about
the climate," continues Xavier Fettweis. By forcing the MAR (Regional Atmospheric Model) developed at ULie`ge to use this scenario, we show
that the reduction in solar radiation associated with this scenario would
make it possible to locally reduce the melting at the surface of the
Greenland ice sheet by 6% in addition to the global reduction in global warming. While these results seem encouraging, the researchers insist
that this type of scenario would not be sufficient to maintain the ice
cap in a stable state by the end of this century. Moreover, this type
of intervention is not without risk since it could have a significant
impact on the ozone layer and on water cycles and precipitation,
accentuating the disparities between wet and dry regions. Only solar geoengineering scenarios, which are much more ambitious but becoming unrealistic and dangerous, would make it possible to save the cap,"
concludes Xavier Fettweis. We are talking here about human and intentional intervention in the climate. A plan B that is not! It is therefore urgent
to drastically reduce our greenhouse gas emissions by means that we know
but are struggling to implement.

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


========================================================================== Journal Reference:
1. Xavier Fettweis, Stefan Hofer, Roland Se'fe'rian, Charles Amory,
Alison
Delhasse, Se'bastien Doutreloup, Christoph Kittel, Charlotte Lang,
Joris Van Bever, Florent Veillon, Peter Irvine. Brief communication:
Reduction in the future Greenland ice sheet surface melt with
the help of solar geoengineering. The Cryosphere, 2021; 15 (6):
3013 DOI: 10.5194/tc-15- 3013-2021 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/07/210707160501.htm

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