Greenland's glaciers are melting 100 times faster than estimated

In this aerial view, icebergs and meltwater are seen in front of the retreating Russell Glacier on Sept. 8, 2021 near Kangerlussuaq, Greenland.
In this aerial view, icebergs and meltwater are seen in front of the retreating Russell Glacier on Sept. 8, 2021 near Kangerlussuaq, Greenland. (Image credit: Mario Tama/Getty Images)

Greenland's glaciers are melting 100 times faster than previously calculated, according to a new model that takes into account the unique interaction between ice and water at the island's fjords. 

The new mathematical representation of glacial melt factors in the latest observations of how ice gets eaten away from the stark vertical faces at the ends of glaciers in Greenland. Previously, scientists used models developed in Antarctica (opens in new tab), where glacial tongues float on top of seawater — a very different arrangement. 

"For years, people took the melt rate model for Antarctic floating glaciers and applied it to Greenland (opens in new tab)'s vertical glacier fronts," lead author Kirstin Schulz (opens in new tab), a research associate in the Oden Institute for Computational Engineering and Sciences at University of Texas at Austin, said in a statement (opens in new tab). "But there is more and more evidence that the traditional approach produces too low melt rates at Greenland's vertical glacier fronts."

The researchers published their findings in September in the journal Geophysical Research Letters (opens in new tab).

Related: 10 devastating signs of climate change we can see from space

Researchers already knew their Antarctica-based understanding of Arctic glaciers was not a perfect match. But it's hard to get close to the edges of Greenland's glaciers, because they're situated at the ends of fjords — long, narrow inlets of seawater flanked by high cliffs — where warm water undercuts the ice. This leads to dramatic calving events where chunks of ice the size of buildings crumble into the water with little warning, creating mini-tsunamis, according to the researchers. 

Researchers led by physical oceanographer Rebecca Jackson (opens in new tab) of Rutgers University have been using robotic boats to get close to these dangerous ice cliffs and take measurements. They've done this at Alaska's LeConte Glacier as well as Greenland's Kangerlussuup Sermia. (An upcoming mission led by scientists at the University of Texas at Austin will send robotic subs to the faces of three west Greenland glaciers. (opens in new tab)) Jackon's measurements suggest that the Antarctica-based models massively underestimate Arctic glacial melt. LeConte, for example, is disappearing 100 times faster than models predicted. 

The mixture of cold fresh water from the glaciers and warmer seawater drives ocean circulation near the glaciers and farther out in the ocean, meaning the melt has far-reaching implications. The Greenland ice sheet is also important for sea-level rise; Greenland ice holds enough water to raise sea levels by 20 feet (6 meters). 

The new model uses the latest data from near-glacial missions along with a more realistic understanding of how the steep, cliff-like faces of the glaciers impact ice loss. The results are consistent with Jackson's findings, showing 100 times more melt than the old models predicted.

"Ocean climate model results are highly relevant for humankind to predict trends associated with climate change, so you really want to get them right," Schulz said. "This was a very important step for making climate models better."

Originally published on LiveScience.

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.

Stephanie Pappas
Live Science Contributor

Stephanie Pappas is a contributing writer for Space.com sister site Live Science, covering topics ranging from geoscience to archaeology to the human brain and behavior. She was previously a senior writer for Live Science but is now a freelancer based in Denver, Colorado, and regularly contributes to Scientific American and The Monitor, the monthly magazine of the American Psychological Association. Stephanie received a bachelor's degree in psychology from the University of South Carolina and a graduate certificate in science communication from the University of California, Santa Cruz. 

  • Ken Fabian
    The loss of ice mass from Greenland is already staggering; no disputing more ice is being lost there than anywhere else. Grace satellite data shows 280 billion metric tons of ice lost per year over the 2002-2021 period - enough to affect sea levels globally by 0.8mm per year. Local to Greenland the effect is the other way around - sea level has been falling in response to the loss of mass and the reduction in the gravitational pull of Greenland on ocean water.

    No alarmist exaggeration - this will have enormous consequences over the coming decades and centuries, especially if commitment to zero emissions lags or gets abandoned. And then there is Antarctica already losing 150 billion tons a year and getting faster. And then there are potential ice sheet collapses that can rapidly accelerate the ice loss.
    Reply
  • PWB
    Nonsense. The mass and extent are well within the decadenal norms going back 40 years. And the Antarctic is the same. More hysteria based on models rather than observation.
    Reply
  • Ken Fabian
    PWB said:
    Nonsense. The mass and extent are well within the decadenal norms going back 40 years. And the Antarctic is the same. More hysteria based on models rather than observation.
    Not nonsense, not hysteria - based on satellite data -


    It is the claims that global warming and Greenland ice loss are nonsense and hysterical that are nonsense and hysterical.

    From different satellites, measuring sea levels, the effects of those mass losses can be observed - in this case the reduction in local gravity causing sea level fall around Greenland -

    VY_SeZiBcM4
    Reply
  • PWB
    It's the AGW that is nonsense. Climate changes, and it always has. The .8mm per year sea level increase. Perhaps. But that's 8cm per century. A little more that 3 inches. Woopee.
    Reply
  • PWB
    You have your stats, I have mine. Greenland is well within the norm.
    Surface Conditions: Polar Portal
    Reply
  • Helio
    The U of Texas article referenced addresses glacier fronts, and not the entire glacier. They report that the melt rate of the floating portion of Antarctic glaciers was the model used for Greenland fronts and other areas where fiords were too problematic for scientists to study. Now robot craft are beginning to get the job done.

    As I see it, it’s not the glaciers that are melting 100x faster, but the ice that reaches the open water (fronts). A 100x increase in glacier melt — as the misleading headline states (UT as well) — would require the flow rate of the entire glacier to have suddenly increased by 100x. That’s not likely!
    Reply
  • Ken Fabian
    PWB said:
    You have your stats, I have mine. Greenland is well within the norm.
    Surface Conditions: Polar Portal
    But there are all those satellites showing real world changes in keeping with, within the range of what has been predicted. I'll continue to take the top level science based expert advice, including IPCC reports as my principle guide and expect and call on my nation's government to have policies in line with it.

    Sure, the climate has always been changing but this argument doesn't work the way you appear to think; the natural propensity of climate to change is why it is so susceptible to raised CO2 levels from fossil carbon burning. If the climate didn't change then raised CO2 would have no warming impact.

    Evidence of past climate changes tells us how serious it can be - which has included mass extinctions and vast regions becoming uninhabitable to humans, with significant global population reductions during the time humans have been around.

    BTW did you actually read that source you linked to? It shows the same ice mass loss as I cited, from the same primary source (Grace satellites). Nowhere does it say Greenland is "within the norm", but all through it says it undergoing significant change. (I keep getting "Something went wrong" when trying to insert the graph image at the link, but - )

    This data shows that most of the loss of ice occurs along the edge of the ice sheet, where independent observations also indicate that the ice is thinning, that the glacier fronts are retreating in fjords and on land, and that there is a greater degree of melting from the surface of the ice.

    PWB said:
    The .8mm per year sea level increase. Perhaps. But that's 8cm per century. A little more that 3 inches. Woopee.

    It is like the first water getting through an ice dam when the Spring thaw starts - it is only getting started and is observed to be accelerating and will accelerate more and accelerate yet more and continue a lot longer if efforts to reach zero emissions are abandoned. There is a lot of uncertainty, but most of that is uncertainty about tipping points that can greatly accelerate ice loss, not uncertainty that ice loss will continue and grow.

    The contribution of Greenland is in combination with thermal expansion and ice mass loss elsewhere, which is also accelerating. ~1 m of global average sea level rise by 2100 will be a lot more than that in many places, eg the US Gulf Coast, where sea levels are already rising about 2x the global average and it doesn't stop at 2100. It is bit like those - "but if we stop our emissions that's not enough" arguments against reducing emissions, that ignore that it isn't just "our emissions", that a whole lot of nations are trying to stop their emissions too, some of them with a lot more commitment and success.

    Helio said:
    As I see it, it’s not the glaciers that are melting 100x faster, but the ice that reaches the open water (fronts). A 100x increase in glacier melt — as the misleading headline states (UT as well) — would require the flow rate of the entire glacier to have suddenly increased by 100x. That’s not likely!
    It won't take this being correct for global warming and sea level rise to have serious impacts. Like the potential for the West Antarctic Ice Sheet to collapse, it can bring the impacts faster but if it doesn't happen like that the impacts will still happen, just taking longer. And abandoning or downgrading efforts to get zero emissions raises the likelihood and the severity.
    Reply
  • Helio
    Ken Fabian said:
    But there are all those satellites showing real world changes in keeping with, within the range of what has been predicted. I'll continue to take the top level science based expert advice, including IPCC reports as my principle guide and expect and call on my nation's government to have policies in line with it.
    The IPCC had the level at 2 to 5 inches by 2100.

    see this Smithsonian article."The new 10-inch metric, which represents about 3.3 percent of Greenland’s total ice, is a higher figure than sea-level rise estimates in other recent forecasts. Last year’s Intergovernmental Panel on Climate Change (IPCC) report, for example, only predicted that Greenland’s melting ice would cause 2 to 5 inches of global sea-level rise by 2100,"
    Regarding satellite data...."This new paper may have come up with a higher number for a few reasons. For one, it relied on satellite measurements instead of the computer modeling that past research used, which are "not up to the task,"

    Reliance on satellite data will change in time, no doubt. Or, they may find the model needs tweaking more than the data. As usual, "More science is needed."

    There is also the question as to when we will see a 10", or more, sea level rise.
    "But Ted Scambos, an ice sheet expert at the University of Colorado Boulder who did not contribute to the study, tells the Post that a longer timescale is probably more accurate: “A lot of the change they forecast would happen in this century, but to get would require several centuries, more perhaps.”

    Others disagree, of course.

    Sure, the climate has always been changing but this argument doesn't work the way you appear to think; the natural propensity of climate to change is why it is so susceptible to raised CO2 levels from fossil carbon burning.
    This is the big question that has yet to be answered. Just how sensitive is our climate to CO2 and many of the other more important variables. How many variables are there? I suspect I could quickly spit out 20, but it may be a hundred more. These variables aren't all independent on a net temperature derivation, they will produce feedback (positive and negative) effects on some of the other variables. It's not just complicated, it's super complicated.

    If the climate didn't change then raised CO2 would have no warming impact.
    Water vapor, methane, etc. also play a roll, thus complicating the ability of modeling.

    Perhaps even more important is understanding the levels of natural variability. The first two assessments from the IPCC favored natural variability as the key to climate change, reportedly.

    Evidence of past climate changes tells us how serious it can be - which has included mass extinctions and vast regions becoming uninhabitable to humans, with significant global population reductions during the time humans have been around.
    It also, at times, allowed huge improvement to the flourishing of thousands of species. What is the ideal temperature for these flourishings?

    We need to transition to better energy sources, but we shouldn't ignore the cost of excessive transitioning at the cost of poor people's lives.

    It is like the first water getting through an ice dam when the Spring thaw starts - it is only getting started and is observed to be accelerating and will accelerate more and accelerate yet more and continue a lot longer if efforts to reach zero emissions are abandoned.
    I'd like to understand, because I lack the knowledge, of what role calfing has on melt rates. From what little I've read, the issue of the ice-ground boundary layer is a big deal, but very complicated.

    It seems clear that zero emissions will likely still give us about 10 inches, at some point. You can't come out of an ice age without melting.
    Reply
  • Ken Fabian
    Helio, would it be fair to say that until you are personally convinced you are not going to support net zero commitments? And that you are not convinced? And that it doesn't move you any closer to being convinced by knowing every science agency that studies climate, every peak science body as well as every IPCC report for more than 30 years says it is real and very serious?

    I think you have every right to hold that position - people who have no specific responsibility around it should be free to think what they like, but I don't think people who do hold relevant posts of high trust and responsibility should have that freedom to pass over the expert advice - which governments have called for and commissioned for the very purpose of informing their decisions. I think governments have a duty of care to seek out the best available expert advice and take it seriously and I think the IPCC reports are representative of that advice, being a summary of and essentially the same as what every science agency and institution doing climate research says.


    We can discuss different aspects and cite various sources and expert opinions back and forth here, as well as our personal ones but I don't expect to convince you that changing the planet's climate is an extremely dangerous and irresponsible thing to do and worth serious effort to limit. If 3 decades of every top level science agencies and their advice saying it is real and serious won't convince you nothing I say here is likely to move you. On the other hand you can't expect to convince me making serious commitments based on that advice is a premature and dangerous thing to do - let alone more dangerous than treating it seriously will be.

    I notice you have clear preference for the lowball estimates and for seeking out and citing reasons to maintain your doubts and oppose zero emissions commitment: finding a ice sheet expert who thinks Greenland ice loss will be a lot slower than the ones that think it is being underestimated: wondering if maybe warming after the last glacial maximum is a cause of sea level rise ("can't come out of an ice age without melting") - nonsense of course; temperature and sea level rise from that topped out 6,000 years ago, which you could look up. You suggest climate change extinctions will end up being a good thing (seriously?). You express concerns that the transition to low emission could hurt the poor - more than unaddressed global warming can - as if this isn't something that climate policy makers haven't been obsessing over all along. Simply your arguments don't sound compelling.

    It seems to me that you will always prefer to find cause to set the mainstream advice aside, just as you make counter arguments to each point I have made, even falling back on ones that are easily shown to be wrong. I don't think you are open to being convinced, I think you are already convinced - that it is overstated ie the expert advice is wrong. That you are optimistic about very little harm from global warming and pessimistic about serious economic harm from zero emissions commitments seems clear. Whereas I am inclined to pessimism about the extent of climate impacts and optimism about the efficacy of solutions.

    I admit to a personal inclination to pessimism but that is not the principle reason I am more inclined to be moved by the higher end projections. In part it is basic risk management - to prepare for the worse case no matter the hope that it doesn't happen.

    But the largest part of my expectation we will remain on a high emissions pathway (and reason I get moved by considering the worse outcomes) is the widespread popularity of views such as PWB's and yours - lots of people that not only don't support strong action to reach zero emissions but lots of people - and political parties and leaders of commerce and industry - who steadfastly oppose it.
    Reply
  • Unclear Engineer
    Ken, While I generally agree with you that global warming has some strong inputs from human activity and that we need to seriously reduce those inputs (and not just CO2 emissions), I think you are hurting your cause in a couple of ways with the rhetoric you are using.

    First, on the science level, there is no ability to claim that "temperature and sea level rise from topped out 6,000 years ago." Actually, looking back at the geological indications of climate over the previous million years, there isn't any sort of "smooth curve" in ice coverage or sea level that one might expect from instantaneous effects from the Milankovitch cycles. There are all sorts of steps and peaks in just one ~100,000 year ice age cycle. Based on geologic evidence, there is no good reason to expect sea level in this particular interglacial period to top out where it stands today. In the previous interglacial period, about 120,000 years ago, sea level topped out about 25' higher than it is, today. So, there is no good evidence that we can actually control sea level so it will stay where it is, right now. The real issue is how fast it might rise in the near future. That is one of the main effects on human well being because of its effects on the infrastructure that support us at this high population density. So, while we do need to work to get our CO2 emissions down, we also need to pull our heads out of the sand and start thinking about how we are going to deal with a sea level rise that we have no hope of preventing, and are having a very hard time figuring out how to even slow down. If you look at the geological records of how fast sea level has risen in the past, naturally, the peak rates are much faster than even the IPCC worst cases. So, reality does not look very convenient.

    Now to the politics. Whenever something like this comes up scientifically, the activists and politicians jump on it to make arguments for their own pre-existing agendas. They tend to distort and even completely misrepresent the science and its implications - usually in both directions. The general public is used to that, and takes government and activist pronouncements with more than the proverbial grain (1/7000 of a pound) of salt. So, my suggestion for maximizing your credibility, and thus your ability to be influential, is never blow smoke about the science! There is too much political talk today about "preventing" or "stopping" sea level rise, when the scientists are actually saying that it is already happening and is going to keep happening at an increasing rate even if we could somehow completely stop emitting CO2 right now.

    The reality is that climate should be expected to change, and if humans had never done anything to affect climate, we could be looking at the beginning of an ice age about now (or 20,000 years from now). We would not like that, either. Humans have used the latest of the rather brief warm periods that have been coming between much longer cold periods to greatly expand our population. What we are enjoying right now is representative of only about 10% of the climate conditions over the last few million years. So, demanding that things be kept as-is is probably well beyond our capabilities.

    But I am not saying that humans can't mess up the climate (and the rest of our environment) to the point that it could be extremely detrimental to us as well as most of the other living inhabitants of our biosphere. I do think we are messing it up to a dangerous level. And, looking at the population dynamics of other species that have had sudden population spikes, those spikes usually end with a crash that takes out the majority of the expanded population - often due to the deleterious effects of the over-population on the environmental factors that allowed for the population explosion to begin.

    So, to me, the real question is whether humans are sufficiently smarter than the other species to foresee the trends and deal with them effectively in time. Frankly, I am not betting on us. But, that doesn't mean I am not rooting for us.
    Reply