Melting of the Antarctic ice sheet could cause multi-meter rise in sea
levels by the end of the millennium

Date:
December 22, 2021
Source:
Hokkaido University
Summary:
Scientists predict that continued global warming under current
trends could lead to an elevation of the sea level by as much as
five meters by the year 3000 CE.



FULL STORY ========================================================================== Scientists predict that continued global warming under current trends
could lead to an elevation of the sea level by as much as five meters
by the year 3000 CE.


==========================================================================
One of the many effects of global warming is sea-level rise due to the
melting and retreat of the Earth's ice sheets and glaciers as well as
other sources. As the sea level rises, large areas of densely populated
coastal land could ultimately become uninhabitable without extensive
coastal modification. It is therefore vital to understand the impact
of different pathways of future climate change on changes in sea level
caused by ice sheets and glaciers.

A team of researchers from Hokkaido University, The University of Tokyo
and the Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
explored the long-term perspective for the Antarctic ice sheet beyond the
21st century under global-warming conditions, assuming late 21st-century climatic conditions remain constant. Their models and conclusions were published in the Journal of Glaciology.

The Ice Sheet Model Intercomparison Project for the Coupled Model Intercomparison Project Phase 6 (ISMIP6) was a major international effort
that used the latest generation of models to estimate the impact of global warming on the ice sheets of Antarctica and Greenland. The objective was
to provide input for the recently published Sixth Assessment Report (AR6)
of the Intergovernmental Panel on Climate Change (IPCC). The contribution
of the Antarctic ice sheet to sea-level rise by 2100 was assessed to be
in the range between ?7.8 and 30.0 centimetres under unabated warming and between 0 and 3 centimetres under reduced emissions of greenhouse gases.

The team used the ice-sheet model SICOPOLIS (SImulation COde for
POLythermal Ice Sheets) to extend the whole ISMIP6 ensemble of fourteen experiments for the unabated warming pathway and three for the reduced emissions pathway. Until the year 2100, the set-up was the same as
in the original ISMIP6 experiments. For the time beyond 2100, it was
assumed that the late 21st-century climatic conditions remain constant --
no further climate trend was applied. The team analysed the results of
the simulations with respect to the total mass change of the ice sheet, regional changes in West Antarctica, East Antarctica and the Antarctic Peninsula, and also the different contributors to mass change.

The simulations of mass loss of the Antarctic ice sheet show that, by the
year 3000, the unabated warming pathway produces a sea-level equivalent
(SLE) of as much as 1.5 to 5.4 metres, while for the reduced emissions
pathway the SLE would be only 0.13 to 0.32 metres. The main reason for
the decay under the unabated warming pathway is the collapse of the West Antarctic ice sheet, made possible by the fact that the West Antarctic
ice sheet is grounded on a bed that is mostly well below sea level.

"This study demonstrates clearly that the impact of 21st-century climate
change on the Antarctic ice sheet extends well beyond the 21st century
itself, and the most severe consequences -- multi-meter contribution to sea-level rise -- will likely only be seen later," says Dr. Christopher Chambers of Hokkaido University's Institute of Low Temperature Science
and lead author of the paper.

"Future work will include basing simulations on
more realistic future climate scenarios, as well
as using other ice-sheet models to model the outcomes." ========================================================================== Story Source: Materials provided by Hokkaido_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Christopher Chambers, Ralf Greve, Takashi Obase, Fuyuki Saito,
Ayako Abe-
Ouchi. Mass loss of the Antarctic ice sheet until the year 3000
under a sustained late-21st-century climate. Journal of Glaciology,
2021; 1 DOI: 10.1017/jog.2021.124 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211222100824.htm

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