Melting glaciers raise sea level

Nov 14, 2012
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: Climate researchers measure the concentration of greenhouse gases above the Atlantic

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 dx.doi.org/10.5194/tc-6-1295-2012

Provided by University of Innsbruck

3.9 /5 (7 votes)
add to favorites email to friend print save as pdf

Related Stories

Melting ice the greatest factor in rising sea levels

Jul 04, 2012

Melting glaciers and ice sheets have contributed more to rising sea levels in the past decade than expansion from warming water, according to modelling in the latest report by the Antarctic Climate and Ecosystems ...

Scientists expect increased melting of mountain glaciers

Jan 20, 2006

Sea level rise due to increased melting of mountain glaciers and polar ice caps will be much lower in the 21st Century than previously estimated. However, decay of mountain glaciers in due to global warming will be much more ...

Warming oceans threaten Antarctic glaciers

Mar 15, 2007

Scientists have identified four Antarctic glaciers that pose a threat to future sea levels using satellite observations, according to a study published in the journal Science.

Recommended for you

NASA sees last vestiges of Tropical Depression Jack

10 hours ago

Tropical Cyclone Jack had weakened to a tropical depression when NASA and JAXA's Tropical Rainfall Measuring Mission (TRMM) satellite passed above on April 22, 2014 at 1120 UTC/7:20 a.m. EDT.

New discovery helps solve mystery source of African lava

13 hours ago

Floods of molten lava may sound like the stuff of apocalyptic theorists, but history is littered with evidence of such past events where vast lava outpourings originating deep in the Earth accompany the breakup ...

Climate change likely to make Everest even riskier

14 hours ago

Climbing to the roof of the world is becoming less predictable and possibly more dangerous, scientists say, as climate change brings warmer temperatures that may eat through the ice and snow on Mount Everest.

User comments : 7

Adjust slider to filter visible comments by rank

Display comments: newest first

Shinobiwan Kenobi
2.6 / 5 (10) 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?
VendicarD
3.5 / 5 (8) 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.
Howhot
3.2 / 5 (9) 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.
Shinobiwan Kenobi
2.5 / 5 (8) 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.
rubberman
2.7 / 5 (7) Nov 16, 2012
My goodness nearly twenty-four hours and nary a denialist in sight...

There's only one who would try and say that warmth doesn't cause ice to melt....he hasn't been around for awhile. Have you seen Lite's profile pic? I might have gone with a different handle....
Shinobiwan Kenobi
2.8 / 5 (6) 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...
Noumenon
1.6 / 5 (7) 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".

More news stories

On global warming, settled science and George Brandis

The Australian Attorney General, Senator George Brandis is no stranger to controversy. His statement in parliament that "people do have a right to be bigots" rapidly gained him notoriety, and it isn't hard to understand why ...