Greenland ice sheet may halve in volume by year 3000

Date:
March 14, 2022
Source:
Hokkaido University
Summary:
As a result of global warming in the 21st century, the Greenland
ice sheet may contribute several meters to sea-level rise in the
centuries to come; however, effective climate change mitigation
measures will greatly reduce its decay.



FULL STORY ==========================================================================
As a result of global warming in the 21st century, the Greenland ice sheet
may contribute several metres to sea-level rise in the centuries to come; however, effective climate change mitigation measures will greatly reduce
its decay.


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

Professor Ralf Greve and Dr. Christopher Chambers at the Institute of
Low Temperature Science, Hokkaido University, simulated the evolution of
the Greenland ice sheet until the year 3000 to investigate the long-term impacts of 21st-century warming. Their predictions 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 of the IPCC (https:// www.ipcc.ch/report/ar6/wg1/). Based on
their contribution to ISMIP6, the research team examined the long-term perspective for the Greenland ice sheet beyond the 21st century under global-warming conditions.

Greve and Chambers used the ice sheet model SICOPOLIS to carry out future projections for each of the twelve ISMIP6 experiments for the unabated
warming pathway and the two experiments for the reduced emissions pathway, extending the time period to the year 3000. The set-up until the year
2100 was the same as for the original ISMIP6 experiments. After 2100,
the climate was assumed to remain the same as at the end of the 21st
century, without considering further warming trends.

An unequivocal distinction between the responses to the unabated warming
and reduced emissions pathways arises. By the year 3000, the unabated
warming pathway causes ice loss of 0.71 to 3.54 meters sea-level
equivalent (SLE), while for the reduced emissions pathway the loss is
only 0.16 to 0.4 meters SLE. These numbers are much larger than for
the 21st century. The melting and retreat of the Greenland ice sheet
occurs in all regions from the far north to the south, and it evolves
gradually over time. Even though the loss can be as large as 50% of the
entire ice volume, it does not develop as a sudden instability.

This study demonstrates clearly that the impact of 21st-century climate
change on the Greenland ice sheet extends well beyond the 21st century
itself, and the most severe consequences -- possibly a multi-meter
contribution to sea-level rise -- will likely only be seen later in
the millennium.

For this study, only a single ice-sheet model (SICOPOLIS) was used,
and the results were obtained under the simplifying assumption of the
constant late- 21st-century climate. In the future, the ISMIP6 community
will conduct simulations with more realistic future climate scenarios
beyond 2100, encompassing the full range from an ongoing, extended warming
to a reduction below 21st-century extremes. Other working groups will contribute results obtained with different ice-sheet models. This will
provide a more complete picture of expected long-term mass loss of the
Earth's ice sheets.


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


========================================================================== Journal Reference:
1. Ralf Greve, Christopher Chambers. Mass loss of the Greenland
ice sheet
until the year 3000 under a sustained late-21st-century
climate. Journal of Glaciology, 2022; 1 DOI: 10.1017/jog.2022.9 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220314105619.htm

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