The melting of the Greenland ice sheet could lead to a sea level rise of
18 cm in 2100

Date:
December 15, 2020
Source:
University of Liege
Summary:
A new study, applying the latest climate models, of which the
MAR predicts a 60% greater melting of the Greenland ice sheet
than previously predicted. Data that will be included in the next
IPCC report.



FULL STORY ==========================================================================
A new study, headed by researchers from the Universities of Lie`ge and
Oslo, applying the latest climate models, of which the MAR predicts a 60% greater melting of the Greenland ice sheet than previously predicted. Data
that will be included in the next IPCC report. This study is published
in Nature Communications.


==========================================================================
The Greenland ice sheet, the second largest after the Antarctic's, covers
an area of 1.7 million square kilometres. Its total melting could lead
to a significant rise in ocean levels, up to 7 metres. Although we are
not there yet, the previous scenarios predicted by climate models have
just been revised upwards, predicting a rise in sea levels of up to 18 cm
by 2100 (compared to the 10 cm announced previously) just because of the increase in surface melting. Within the framework of the next IPCC report
(AR6) which will appear in 2022, the University of Lie`ge Laboratory of climatology has been led to apply, within the framework of the ISMIP6
project, the MAR climate model which it is developing to downscale the
old and new IPCC scenarios. The results obtained showed that for the
same evolution of greenhouse gas concentrations till 2100, these new
scenarios predict a 60% greater surface melting of the Greenland ice
cap than previously estimated for the previous IPCC report (AR5, 2013).

The MAR model was the first to demonstrate that the Greenland ice sheet
would melt further with a warming of the Arctic in summer. While our MAR
model suggested that in 2100 the surface melting of the Greenland ice
sheet would contribute to a rise in the oceans of around ten centimetres
in the worst-case scenario (i.e. if we do not change our habits),"
explains Stefan Hofer, post- doc researcher at the University of Oslo,
"our new projections now suggest a rise of 18 cm." As the new IPCC
scenarios are based on models whose physics have been improved -- in
particular by incorporating a better representation of cloudiness --
and whose spatial resolution has been increased, these new projections
should in theory be more robust and reliable.

The team of the Laboratory of Climatology was the first to downscale
these scenarios on the Greenland ice cap. "It would now be interesting,
says Xavier Fettweis, researcher and director of the Laboratory, to
analyse how these future projections are sensitive to the MAR model
that we are developing by downscalling these scenarios with other models
than MAR as we have done on the present climate (GrSMBMIP)." This study
will be carried out within the framework of the European project PROTECT (H2020). The objective of this project is to assess and project changes
in the terrestrial cryosphere, with fully quantified uncertainties,
in order to produce robust global, regional and local projections of
sea level rise over a range of time scales.

The data collected as part of the Katabata project, launched last
September by Xavier Fettweis and his colleague Damien Ernst, will also
help to refine the models, particularly the wind model-ling in the MAR
climate model. "Knowing that the wind influences the melting of the
ice sheet, it is important to have the most reliable models possible,
concludes Xavier Fettweis."

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


========================================================================== Journal References:
1. Fettweis et al. GrSMBMIP: intercomparison of the modelled 1980-2012
surface mass balance over the Greenland Ice Sheet. The Cryosphere,
2020 DOI: 10.1038/s41467-020-20011-8
2. Hofer, S., Lang, C., Amory, C. et al. Greater Greenland Ice Sheet
contribution to global sea level rise in CMIP6. Nat Commun, 2020
DOI: 10.1038/s41467-020-20011-8 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/12/201215112018.htm

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