A new study combined GPS, satellite data, and numerical modeling. It found ice loss from northeast Greenland could be six times greater by the end of the century than previously thought.
Ice is continuously streaming off Greenland’s melting glaciers at an accelerating rate, dramatically increasing global sea levels. New results published in the journal Nature on November 9 indicate that existing models have underestimated how much ice will be lost during the 21st century. Hence, its contribution to sea-level rise will be significantly higher.
By 2100, the Northeast Greenland Ice Stream will contribute six times as much to the rising sea level as previous models suggested, adding between 13,5 to 15,5 mm (0.53 to 0.61 inches), according to the new study. This is equivalent to the entire Greenland ice sheet’s contribution in the past 50 years. Scientists from Denmark, the United States, France, and Germany carried out the research.
“Our previous projections of ice loss in Greenland until 2100 are vastly underestimated,” said first author Shfaqat Abbas Khan, Professor at the National Space Institute at the Technical University of Denmark (DTU Space).
“Models are mainly tuned to observations at the front of the ice sheet, which is easily accessible, and where, visibly, a lot is happening.”
Animation of modeled frontal positions from 2007 to 2100. A Landsat-8 image from 2017 is used as the background. The color denotes the surface speed. Credit: Animation by Shfaqat Abbas Khan, DTU Space, Denmark
Ice loss occurs more than 200 km inland
The study is partly based on data collected from a network of precise GPS stations reaching as far as 200 km inland on the Northeast Greenland Ice Stream—located behind the Nioghalvfjerdsfjord Gletscher and Zachariae Isstrøm glaciers, one of Earth’s most hostile and remote terrains. The GPS data were combined with surface-elevation data from the CryoSat-2 satellite mission and high-resolution numerical modeling.
“Our data show us that what we see happening at the front reaches far back into the heart of the ice sheet,” said Khan.
“We can see that the entire basin is thinning, and the surface speed is accelerating. Every year the glaciers we’ve studied have retreated further inland, and we predict that this will continue over the coming decades and centuries. Under present-day climate forcing, it is difficult to conceive how this retreat could stop.”
Animation of modeled surface elevation change from 2007 to 2100. A Landsat-8 image from 2017 is used as the background. The colors denote surface elevation change. Negative values denote thinning/surface lowering. Credit: Animation by Shfaqat Abbas Khan, DTU Space, Denmark
Significant contribution to rising sea levels
In 2012, after a decade of melting, the floating extensions of Zachariae Isstrøm collapsed, and the glacier has since retreated inland at an accelerating pace. And though winter 2021 and summer 2022 have been particularly cold, the glaciers keep retreating. Since northeastern Greenland is a so-called Arctic desert – precipitation is as low as 25 mm per year in places – the ice sheet is not regenerating enough to mitigate the melt. However, estimating how much ice is lost and how far into the ice sheet the process occurs is not easy. The ice sheet’s interior, which moves at less than one meter per year, is difficult to monitor, which limits the ability to make accurate projections.
“It is truly amazing that we are able to detect a subtle speed change from high-precision GPS data, which ultimately, when combined with a model of ice flow, inform us on how the glacier slides on its bed,” said coauthor Mathieu Morlighem, a professor of earth sciences at Dartmouth College.
“It is possible that what we find in northeast Greenland may be happening in other sectors of the ice sheet. Many glaciers have been accelerating and thinning near the margin in recent decades. GPS data helps us detect how far this acceleration propagates inland, potentially 200-300 km from the coast. If this is correct, the contribution from ice dynamics to the overall mass loss of Greenland will be larger than what current models suggest.”
The Zachariae Isstrøm was stable until 2004, followed by steadily retreat of the ice front until 2012, when a large portion of the floating sections became disconnected. As more precise observations of change in ice velocity are included in models, it is likely that IPCC’s estimates of 22-98 cm global sea level rise will need to be corrected upwards.
“We foresee profound changes in global sea levels, more than currently projected by existing models,” said coauthor Eric Rignot, professor of Earth system science at the University of California, Irvine.
“Data collected in the vast interior of ice sheets, such as those described herein, help us better represent the physical processes included in numerical models and in turn provide more realistic projections of global sea-level rise.”
Reference: “Extensive inland thinning and speed-up of Northeast Greenland Ice Stream” by Shfaqat A. Khan, Youngmin Choi, Mathieu Morlighem, Eric Rignot, Veit Helm, Angelika Humbert, Jérémie Mouginot, Romain Millan, Kurt H. Kjær and Anders A. Bjørk, 9 November 2022, Nature.
Sounds to me like the researchers need more grant money. Also, there is not a goddam thing you can do about climate change. It took Humans 200 years to create it. You can’t wave your science wand and make it go away. So…stop making us buy your fuking science wands that will never work. Go dig wells in Africa if you want to change the world. Nerds.
Wow you are an angry little bitch.
We will adapt, innovate and survive. All of the freaking out won’t change anything. It is here and all of the options provided by 10 yr old emotional level evironmentalists(?) won’t change a thing now or later. Mother Nature rules, always has, always will. Earth will be fine, man will also, although his numbers will be thankfully greatly reduced.
Is is sad that the angry and hostile person identified as “The 10th Man”, likely a Trump supporter, feels compelled to made derisive comments regarding climate scientists, whose work they cannot possibly understand.
In all the comments that he has written in any of these bulletins, on any subject – he particularly hates NASA – he has never once written anything complimentary or positive. He only says what he says to get attention – which he now has, so I guess we have made him happy.
What this and other similar “studies” tells us is that model forecasts are not the “settled science” we have relied on to make “urgent” cuts in our CO2 emissions. There is little to nothing that can possibly be done to have any effect on sea levels or global temp[ertures. We should give up on those grandiose and costly schemes and start developing better infrastructures to deal with extreme weather…hot or cold. It will have to be done anyhow.
Build dams a certain height, move crops and people elsewhere… if we don’t decarbonize, chances are the climate will only keep getting worse/crazier, and no solutions will last more a few decades. It’s an unfathomable cost.
The math presented is useless as it tries to compare lad areas that are not defined, so how is a reader supposed to understand what the quantities referenced mean? If the Northern Ice sheet (its previous 50 years contribution unstated) will add .5 to .6 Inches in the next 78 years (by 2100), how are we supposed to relate that to the claim that it is equal to what the whole Greenland sheet melted in the past 50 years. Please, provide data that can be understood.
So the sea level rise is up to 1m over the next hundred years. Oh no, the world is going to end. Just like it ended when the sea level rose 1 meter over the last 200 years.
“Future Sea-Level Rise May Be Much Higher Than Thought”
The words “may” and “thought” are the issue. If climate change needs hundreds of trillions of dollars to alleviate, there needs to be six-sigma-level-certainty before taking money from everyone on the planet. This headline/story sounds like “Economic model correctly predicted nine of the last five recessions”.
This “10th Manchild” fellow sounds like a happy, well adjusted true academic, which is exactly why he is here contributing to a science based discussion. He cares so much about climatology that he uses reverse psychology in a transparent attempt to drum up support for further funding of future studies. I’m sure he’d be the first to admit that it is the progression of science which allows him access to online content with his electronic devices (while in Africa digging wells).
I think it is important to note that the abstract for the article says, “Whether continuing increased ice loss will accelerate further, and by how much, remains contentious.”
Apparently, “A notable change occurred in 2012, when the ice shelf collapsed and the ice flow accelerated.” If the ice shelf was grounded, it would have impeded forward motion. The subsequent thinning can be explained by the ice increasing in velocity with consequent thinning. In fact, they note, “We found that the friction laws that are almost plastic are able to reproduce deep inland acceleration and thinning with remarkably good agreement (Fig. 2d,e), as well as reproducing the observed mass loss from 2011 to 2021 (Fig. 4).” An alternative working hypothesis is that this is a transitory adjustment resulting from structural changes, rather than just melting.
The point of the research is to try to predict future sea level rise. Where is the evidence that the changes over the last decade have increased sea level? If that evidence is not available, then it calls into question the veracity of predictions decades into the future.
By 2100 … adding between 13,5 to 15,5 mm (0.53 to 0.61 inches)
Seems to me one-half inch over the next 80-years is minuscule in the grand scheme of things. Or am I missing something?
I was thinking the same thing! But farther down the same article postulates bigger rises–22 to 98 cm. But the range is extreme- by a factor of five, so the model is not very predictive.
Thanks, but it’s still not clear to me. 22-98 cm + 13,5 to 15,5 mm, still is only a slight increase in the model. In terms of overall volume that’s a huge number, but in terms of elevation, not so much.
Better for the fishies!
Ok, so the ice is melting and sea levels are rising. On land we have periods – sometimes extended periods of drought.
So, the question becomes wh6y are we not talking about desalination? Why are we having conversations about global warming, yet ignoring the opportunity that the process may afford us? We use millions of gallons of fresh water daily, it is essential to our survival.
We know that the oceans are filling up, and land is threatened. So the question becomes why are we not talking about large scale desalination?
Israel probably leads the entire world in desalination, they went from a shortage of fresh water supply to an excess supply of water – in large part because they developed numerous desalination plants.
Seems to me, instead of all these global climate conferences that involve a lot of hand wringing and conversations about stopping climate change, and that is important, BUT, it seems we are missing an opportunity to capitalize on the consequences of global warming.
Build enough desalination plants, such the water out of the oceans, and work on mitigating sea level rise by turning sea water into useable fresh water.
If all the fresh water is extracted from the ocean water, how do you dispose of the remaining mix of salts? If only some fresh water is removed, the remaining brine will undoubtedly be toxic to every living thing in the ocean locally, if dumped in the ocean. What do you propose to do about that?
Don’t dump the remaining brine in the ocean.
Instead, allow all the water to evaporate away leaving the solid salt behind. Put it into crates and ship them to the highest bidder.
Both salt and fresh water are products that can be sold. Nothing needs to be dumped back into the ocean.
It isn’t that simple. In commercial operations, the salt water is placed in temporary holding ponds that allows the least soluble minerals, such as gypsum, to crystalize out. The concentrated brine is then moved to different ponds where the sodium and potassium chlorides are precipitated. That material is then re-dissolved to eliminate dirt, dust, and other organic impurities (such as dead algae), and re-precipitated. Those are energy using operations. There is no such thing as as a free lunch.
Sure, it makes sense that desalination steps, like pumping water between ponds, would be energy-using operations. (I do hope the energy used would come from renewable sources like wind or solar, so as not to contribute to climate change.)
But at the end of this energy-using process, there’s a leftover toxic brine. Apparently some desalination plants dump this toxic brine back into the ocean, and that has given desalination a bad name. Well, they shouldn’t do that!
Instead, the end of this energy-using process should be a final step that gets rid of all the water, leaving only solids, to be shipped AWAY from the ocean instead of towards it. That can’t be impossible.
(It might be expensive, but then desalinated water is expensive. No-one expected it to be cheap. Perhaps over time, technological improvements will make it cheaper, as has happened with solar panels.)
The remaining salt solids can be used to treat our roads, driveways, sidewalks etc… during the winter or possibly used as sea salt for cooking if pure enough.. Brine may slso contain unanium which could be extracted and sold off setting the costs of building and operating desalination plants. The remaining brine can be sent to New Jersey where the Governor is proud of his use of brine to pre-treat roads prior to winter snow and ice storms. Other states could adopt New Jersey’s brine processes as well.
Captain Obvious, you remarked, “It might be expensive, but then …” What “expensive” means is that it is another demand for energy.
Ric, the use of salt or brine is not without its environmental impacts, not to mention what it does to cars.
The 10th man wow ur an asshole and an idiot thanks to these extraordinary people we have cures for covid 19 AIDS Etc. And global warming is f****** real remember that ….
Hurricanes, cyclones, high heat- all increasingly strong due in part to abrupt climate change. Assuming we are helpless in the face of increasingly harsh weather, yearly, practical answers require practical science. Electric airplanes, battery driven solar building generators and HVAC as well as EV vehicles still contribute to comparatively lower heating levels on Earth compared to internal combustion engines. But new architecture and also… water reclamation…are of extreme importance in coming generations. Prayer, and teaching new ways to accomplish what is forecast to be a new set of Earth realities has helped humankind through eons of evolution. Our time period might seem different than the past, but if humans are as resilient-and practical- as the proto-humans who preceded homo sapiens, then we stand a true chance at both survival and…..human evolution as well-even if we have to do things somewhat differently and…..dig wells as 10 said, in Africa…..
“practical answers require practical science.” There are no practical and realistic ways to keep the global temperature from rising even if if you believe that CO2 is the “control knob” Using all of our resources to adapt is the only practical way forward. Continuing to believe in the dire forecasts of climate models should be left to academics and their lattes in the faculty lounges.
The last Ice Age started melting 10-12 thousand years ago. The ice covered Canada and maybe 30 percent or more of the northern US of America. Earlier ice ages have been documented, as well as the planet’s pollution this planet creates its self-volcanoes, lightning-caused forest fires, methane vents from the ocean floor and only God knows what else, other than human-caused forest/buildings and fossil fuels consumption/garbage dumps and deforestation (less trees-less lightning-caused forest fires), the people on this planet may have increased global warming, and maybe not. Who was here at the 2nd, or any previous Ice Age? What starts an ice age. This planet is a living,breathing entity, all it’s own. We don’t understand the oceans other than garbage sucks let alone the cosmos or anything in between. We don’t understand our purpose here or much of anything. Hell, maybe God’s stop watch is on count down. Has anyone ever noticed the ice cubes in a cooler melt faster(exponentially) the less there are. How about the way people try to control people based on fear? This last political session should confirm that. We don’t even understand why (as a whole) like each other.
Seems kinda weird to me. We are in droughts in many places. In fact some areas are vastly dry to the point where you can see the foundations of structures built more then 30 feet below the water level. So if the glaciers melt, doesn’t it just replenish what we have lost? It would level out and later the glacier grow again and it does it over and over. The earth was build by a perfect creator to be forever, just wait till he fixes the people on it, then everything will go back into balance