Melting glaciers raise sea level

Melting glaciers raise sea level
Until 2300, we can expect the sea level to rise between 25 and 42 cm due to glacier melt. With 42 cm sea level rise, most of the glaciers of the world will be gone, leaving behind only small remains in very high altitudes. Credit: Ben Marzeion

Anthropogenic climate change leads to melting glaciers and rising sea level. Between 1902 and 2009, melting glaciers contributed 11 cm to sea level rise. They were therefore the most important cause of sea level rise. This is the result of a new assessment by scientists of the University of Innsbruck. They numerically modeled the changes of each of the world's 300 000 glaciers. Until 2100, glaciers could lead to an additional 22 cm of sea level rise.

Since 1900 the global sea level has risen by approximately 20 cm. Melting glaciers are one of the causes – along with warming and thereby expanding sea water, melting Greenland and Antarctic ice sheets, and changing terrestrial water storage in dammed lakes and groundwater reservoirs. A team of scientists at the University of Innsbruck has now assessed the contribution of melting glaciers to sea level rise during the 20th century. They numerically modeled each of the world's roughly 300 000 glaciers and used thousands of on-site measurements to validate the model results. "These calculations show that between 1902 and 2009, glaciers contributed about 11 cm to sea level rise", says Dr. Ben Marzeion from the Institute for Meteorology and Geophysics. "This means they were the most important cause of sea level change." Surprisingly, melt rates were more or less constant over time: While temperatures during the first decades of the 20th century were considerably lower, glaciers were larger and extended into lower and thus warmer areas. Additionally, brief but strong warm episodes in the Arctic led to strong glacier retreat in the Arctic in the 1930s and 1950s.

Using 15 different climate models, the Innsbruck scientists also investigated the future fate of the glaciers. "There are big regional differences", says Dr. Marzeion. "Also the future behavior of humankind is important – i.e., how much carbon dioxide and other greenhouse gases will be emitted." In the climate models four different scenarios of future economic, social, and technological development were used to represent different levels of greenhouse gas emissions. "Regions with small glaciers, such as the Alps, will lose a large fraction of their ice during the coming decades", explains the climate scientist. "In the Alps, half of the ice will be gone by approximately 2040. But in absolute numbers, this loss is relatively small: until then, the Alps will contribute only 0.2 mm to sea level rise." Regions with large glaciers, however, will lose a lot of mass in absolute numbers, while a relatively large fraction remains: "In the Canadian Arctic about 70% of the ice will remain in 2100, but this region alone will have contributed about 2 cm to sea level rise by then", says Ben Marzeion.

Melting glaciers will raise the sea level between 15 and 22 cm until 2100. "Where we end up within this range is up to us – it mostly depends on how much greenhouse gas we will emit", says Marzeion. The same is true for the longer term: "Until 2300, we can expect the sea level to rise between 25 and 42 cm due to glacier melt. With 42 cm sea level rise, most of the glaciers of the world will be gone, leaving behind only small remains in very high altitudes." But also in the future, warming and thus expanding sea water, melting of the Greenland and Antarctic ice sheets, and changing terrestrial water storage have to be added to obtain the full sea level rise.

Explore further

Melting ice the greatest factor in rising sea levels

More information: Past and future sea-level change from the surface mass balance of glaciers. B. Marzeion, A. H. Jarosch, and M. Hofer. The Cryosphere, 6, 1295-1322, 2012 DOI:10.5194/tc-6-1295-2012
Provided by University of Innsbruck
Citation: Melting glaciers raise sea level (2012, November 14) retrieved 20 August 2019 from
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Feedback to editors

User comments

Nov 15, 2012
My goodness nearly twenty-four hours and nary a denialist in sight...
What will we see first: cherry-picked data, a diatribe against computer-modeling, or assertions that 97% of scientists are being paid to scare the public?

Nov 15, 2012
They have grown oddly silent ever since the Republicans had their backsides kicked in the last election.

It seems that they have been called away to join the campaign to drive the U.S. economy into the ground and then blame Obama.

They need to manufacture an economic crisis in order to assure that there are no alternatives to a smaller government.

Nov 15, 2012
Well Kenobi, someone oddly knocked you down to one on the rank scale, so they are out there. I suspect they are so pissed off loosing to Obama and seeing THEIR great country flip to socialism (no that's not strong enough... call it communism) that most of their minds have exploded into a quivering lump of pulsing goo.

Nov 16, 2012
It's just Lite (ranks 1s everwhere and never comments) and some other nimrod.

Vendicar, they must be busy signing/submitting petitions for secession.

Nov 18, 2012
I was expecting the other regulars to pipe-up but it seems they are content with down-ranking rather than spewing their nonsense across their keyboards.

As for lite's pic: beefy...

Nov 18, 2012
""...if the message is somehow that we're going to ignore jobs and growth SIMPLY to address climate change, I don't think anybody's going to go for that. I won't go for that," - B.H. Obama

Ooohh, what a shame. Doesn't seem like the novelty president has a sense of urgency with respect to AGW,.... and further doesn't appear to have much faith in the green industry either, as supposedly that was "going to create jobs".

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more