Greenlands Height Increasing as Glaciers Melt
Posted by admin on 2024-02-12 |
Glacial ice flowing off the edges of Greenland is causing
the landmass to rise, akin to a decompressing mattress. The uplift of Greenland
is a well-established long-term process. Since the conclusion of the last ice
age approximately 11,700 years ago, the retreat of the ice sheet has relieved
weight from Greenland, enabling its bedrock to ascend-a phenomenon known as
glacial isostatic rebound. Concurrently, modern-day climate change is leading
to ice loss from the Greenland Ice Sheet. Research from 2022 indicates that
approximately 262 gigatons of ice are shed annually, with peripheral glaciers
losing about 42 gigatons of ice alone.
A
recent study published in the journal Geophysical Research Letters, dated
January 13, reveals that this loss of glacial ice significantly contributes to
Greenland’s bedrock rise. In certain areas, glacial ice loss accounts for
nearly a third of the total vertical land motion. Danjal Longfors Berg, a
doctoral student at the Technical University of Denmark, notes, “The maximum
land uplift is where you have the most mass loss, and that's closest to the
biggest glaciers in Greenland.”
Berg
and his team utilized data from 58 GPS monitors drilled into the bedrock around
Greenland since 2007 to measure vertical motion. Subsequently, they
distinguished the contributions of current and recent ice loss from longer-term
rebound. The findings indicate that glacier ice loss is responsible for substantial
portions of Greenland’s rise—32% and 27.9% of the total rebound in two drainage
basins in the northern and eastern parts of the landmass, respectively.
Notably, the largest rate of bedrock rebound is observed near Kangerlussuaq
Glacier in southeast Greenland, where the ground is rising at approximately 0.3
inch (8 millimeters) per year. Since 1900, this glacier has retreated 6.2 miles
(10 kilometers) and has thinned near its terminus by hundreds of meters.
Understanding
Greenland’s bedrock rise provides an additional means of gauging ice loss in
the region, Berg asserts. This complements other methods such as altimetry and
gravity measurements obtained via satellite. By combining vertical land motion
with these techniques, precise assessments of ice disappearance can be made,
facilitating better estimates of rising sea levels. Berg emphasizes, “When we
estimate how much mass it's losing, then we can give a better estimate of how
much the sea level is rising.”
