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Melting ice sheets will add over 15 inches to global sea level rise by 2100

Melting from ice shelves in Greenland and Antarctica (like the Getz Ice Shelf seen here) will contribute over 15 inches to global sea level rise by 2100, scientists have found in a new study.  (Image credit: Jeremy Harbeck/NASA)

If humans continue emitting greenhouse gases at the current pace, global sea levels could rise more than 15 inches (38 centimeters) by 2100, scientists found in a new study. 

Greenhouse gases emitted by human activity, such as carbon dioxide, contribute significantly to climate change and warming temperatures on planet Earth, studies continue to show. As things heat up, ice sheets in Greenland and Antarctica melt. A new study by an international team of more than 60 ice, ocean and atmospheric scientists estimates just how much these melting ice sheets will contribute to global sea levels. 

"One of the biggest uncertainties when it comes to how much sea level will rise in the future is how much the ice sheets will contribute," project leader and ice scientist Sophie Nowicki, now at the University at Buffalo and formerly at NASA's Goddard Space Flight Center in Maryland, said in a statement. "And how much the ice sheets contribute is really dependent on what the climate will do."

Related: The reality of climate change: 10 myths busted

The results of this study show that, if human greenhouse gas emissions continue at the pace they're currently at, Greenland and Antarctica's melting ice sheets will contribute over 15 inches (28 centimeters) to global sea levels. This new study is part of the Ice Sheet Model Intercomparison Project (ISMIP6), which is led by NASA Goddard. 

The ISMIP6 team investigated how sea levels will rise between 2015 and 2100, exploring how sea levels will change in a variety of carbon-emission scenarios

They found that, with high emissions (like we see now) extending throughout this time period, Greenland's melting ice sheet will contribute about 3.5 in (9 cm) to global sea level rise. With lower emissions, they estimate that number to be about 1.3 in (3 cm). 

Ice sheet loss in Antarctica is a little more difficult to predict, because, while ice shelves will continue to erode on the western side of the continent, East Antarctica could actually gain mass as temperatures rise because of increasing snowfall. Because of this, the team found a larger range of possible ice sheet loss here.

The team determined that ice-sheet loss in Antarctica could boost sea levels up to 12 in (30 cm), with West Antarctica causing up to 7.1 in (18 cm) of sea level rise by 2100 with the highest predicted emissions. 

However, to be clear: These increases in global sea levels are just predictions for the years 2015 to 2100, so they don't account for the significant ice sheet loss that has already taken place between the pre-industrial era and modern day. 

"The Amundsen Sea region in West Antarctica and Wilkes Land in East Antarctica are the two regions most sensitive to warming ocean temperatures and changing currents, and will continue to lose large amounts of ice," Helene Seroussi, an ice scientist at NASA's Jet Propulsion Laboratory in Southern California, who led the Antarctic ice sheet modeling in the ISMIP6 project, said in the same statement. 

"With these new results, we can focus our efforts in the correct direction and know what needs to be worked on to continue improving the projections," Seroussi said.

These results are in line with estimates made by the Intergovernmental Panel on Climate Change (IPCC), whose 2019 Special Report on Oceans and the Cryosphere showed that melting ice sheets would contribute to about one-third of the total global sea level rise. 

According to the 2019 IPCC report, melting ice sheets in Greenland will contribute 3.1 to 10.6 inches (8 to 27 cm) to global sea level rise between the years 2000 and 2100. For Antarctica, the report estimates that melting ice sheets will add 1.2 to 11 inches (3 to 28 cm). 

The results from this new work will help to inform the next IPCC report, the sixth overall, which is set to be released in 2022, according to the same statement. 

"The strength of ISMIP6 was to bring together most of the ice sheet modeling groups around the world, and then connect with other communities of ocean and atmospheric modelers as well, to better understand what could happen to the ice sheets," Heiko Goelzer, a scientist from Utrecht University in the Netherlands who is now at NORCE Norwegian Research Centre in Norway, said in the same statement. 

"It took over six years of workshops and teleconferences with scientists from around the world working on ice sheet, atmosphere, and ocean modeling to build a community that was able to ultimately improve our sea level rise projections," added Nowicki, who led the Greenland ice sheet ISMIP6 project. "The reason it worked is because the polar community is small, and we're all very keen on getting this problem of future sea level right. We need to know these numbers."

This work was published Sept. 17 in a special issue of the journal The Cryosphere.

Email Chelsea Gohd at cgohd@space.com or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

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  • Erny_Module
    Reply
  • c1p43r z3r0
    say buh-bye to all those 15 inch high islands out there...
    Reply
  • NewGTGuy
    In 1982 NASA said that Southern California and Florida would be underwater in 30 years. All these so called "climate scientists" have a dreadfully inaccurate record. Fool me once, shame on you. Fool me twice.... you know how it goes... NEXT!
    Reply
  • WKBeaty1
    Well I did the math a few years back when, again, Antarctica was melting out of control. And it showed as the temps warm, the atmosphere (troposphere) will absorb all or most of the water from the melting ice. Could the authors of this study explain how they handled the increased caring capacity of the air as it heats up? Just 1.5 C increase adds a lot of water caring capacity to the atmosphere. Also as cold areas become temperate, plants and bio-activity also absorb a lot of water. More water in the air and maybe deserts become green... We see the "greening" affect already. It is not always the end of the world, just seems to be a group that wants it to be the end of the world.
    Reply
  • Helio
    The news a few years a go that there were over 135 volcanoes found under the ice sheet I trust was in their modeling, but why not mention them or have they been debunked? I need to be convinced that the modeling is solid and that "consensus science" is distinguished from "agenda science", which often has the greater financial rewards. We all are guilty of tending to believe what we want to believe, especially me, admittedly.
    Reply
  • Ranbud
    So tell me this, How much has the ocean risen in the last million or so years as the ice sheets that covered north America have melted, even when there were no humans it seems the earth was getting warmer, How did that happen????
    Reply
  • abrickell
    Admin said:
    A new, international study shows the significant impact that melting ice sheets will have on global sea levels.

    Melting ice sheets will add over 15 inches to global sea level rise by 2100 : Read more
    This article has nothing to do with space. It should be on a climate change website, not space.com. Please stick to your knitting!
    Reply
  • Erny_Module
    Ranbud said:
    So tell me this, How much has the ocean risen in the last million or so years as the ice sheets that covered north America have melted, even when there were no humans it seems the earth was getting warmer, How did that happen????
    Climate scientist: "Oh, that's irrelevant, because reasons! Anyway, by adding "corrections' and 'adjustments' we can easily make all that go away. " Bad humans!
    Reply
  • Sproly
    NewGTGuy said:
    In 1982 NASA said that Southern California and Florida would be underwater in 30 years. All these so called "climate scientists" have a dreadfully inaccurate record. Fool me once, shame on you. Fool me twice.... you know how it goes... NEXT!
    I remember specifically growing up in the 90s that I had old at the time textbooks claiming NYC would be underwater by the year 2000. Then in HS, textbooks claimed the entire eastern seaboard of the US would be underwater by 2020. As I graduated college that date was pushed back to 2050. Now I see it's further pushed back to 2100. The beauty of climate science is that you can just keep pushing the date back indefinitely and nobody can question if your models are at all accurate (as one would in the face of repeated instances of inaccuracy) lest you run the risk of being called a "climate denier". They've got it all figured out. That sweet grant money will always keep rolling in.
    Reply
  • Ken Fabian
    This has brought out the lurking climate science deniers, but I am not impressed. Pseudonymous pseudo-experts verses people and institutions that actually measure and study the questions? There is no competition.

    All the top level science is dismissed because a media article quoted someone who said something that was wrong - but not interested in all that climate science has got right?

    A worst case scenario getting publicised that ended up being closer to the most likely ? When the most likely is about where we are now, ie with every real world measure and indicator showing a warming climate system.

    Global surface temperatures - still rising.
    Ocean Heat content - still rising.
    Global Sea Levels - still rising.
    Sea Surface temperatures - still rising.
    Sea ice extent - still shrinking.
    Sea ice concentration - still decreasing.
    Ice Sheet mass loss - still increasing.
    Global Snow cover - decreasing.
    Etc, Etc - for every change that indicates warming.

    I think the significance of Near Earth Space and satellite technology is profound; beyond Near Earth may have great appeal but it is where the greatest benefits are being realised. All those invaluable satellites that look down are showing that global warming is really happening. Grace, Aqua, Aura, Calypso, Cloudsat, Icesat, Grace, Geocarb etc, etc... all giving data that confirms and informs - and none of them showing climate change is false or insignificant.
    Reply