Two new satellite images remind us that Earth's ice sheets are losing so much mass it's becoming obvious from space.
In the vivid new maps published as part of an April 30 study in the journal Science, researchers illustrated 16 years of ice loss in Greenland and Antarctica as seen by a laser-emitting NASA satellite. The images paint a picture of rapid melt around the coasts of both regions (shown in red and purple in the maps), far outweighing modest ice-mass gains (shown in light blue) farther inland.
Greenland's ice sheet lost an average of 200 gigatons of ice per year, while Antarctica's ice sheet lost an average of 118 gigatons per year; for reference, a single gigaton of ice is enough to fill 400,000 Olympic-sized swimming pools, the researchers said in a statement.
All that melting ice was responsible for a total 0.55 inches (14 millimeters) of sea-level rise between 2003 and 2019, the researchers found. That rise puts Earth on track for the worst-case climate warming scenario laid out in the Intergovernmental Panel on Climate Change's (IPCC) latest report, previous research found. That scenario would put hundreds of millions of people living in coastal communities at risk of losing their homes — or their lives — to flooding.
For the new study, the researchers used the newest data from NASA's ICESat-2 satellite, which launched in 2018 to monitor elevation changes on land (and ice) around the world by bathing the planet in laser beams. The team compared 2019 elevation levels with data recorded by the satellite's predecessor — named simply ICESat — between 2003 and 2009. At thousands of locations where the two datasets overlapped, the team could see precisely how much ice had vanished from Greenland and Antarctica between 2003 and 2019.
Ice shelves — enormous ledges of ice floating over the ocean at the edges of Greenland and Antarctica — lost the most mass by far in both regions, the researchers said. While ice shelves are already partially submerged in water and therefore do not actively raise sea levels when they melt, they provide a structural integrity to glaciers that prevents ice farther inland from gushing into the sea.
"It's like an architectural buttress that holds up a cathedral," study co-author Helen Amanda Fricker, a glaciologist at Scripps Institution of Oceanography at the University of California, San Diego, said in the statement. "The ice shelves hold the ice sheet up. If you take away the ice shelves, or even if you thin them, you're reducing that buttressing force, so the grounded ice can flow faster."
Predictably, the new research shows, as the ice shelves surrounding Antarctica and Greenland have thinned and melted over the last two decades, grounded ice farther inland has thinned and melted too.
The new analysis reveals, with unprecedented detail, the response of these ice sheets to changes in climate, "revealing clues as to why and how the ice sheets are reacting the way they are," study co-author Alex Gardner, a glaciologist at NASA's Jet Propulsion Laboratory in Pasadena, California, said in the statement.
- Images of melt: Earth's vanishing ice
- The reality of climate change: 10 myths busted
- Top 10 ways to destroy Earth
Originally published on Live Science.
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Brandon is the space/physics editor at Live Science. His writing has appeared in The Washington Post, Reader's Digest, CBS.com, the Richard Dawkins Foundation website and other outlets. He holds a bachelor's degree in creative writing from the University of Arizona, with minors in journalism and media arts. He enjoys writing most about space, geoscience and the mysteries of the universe.
Anyone paying attention to NO sunspots and shift of the magnetic pole... hmmmmm.Reply
Why are we so determined that Antarctica should not melt? It's a useless hunk of ice now. Anyway how can two years worth of laser scanning amount to any conclusions regarding the history of Antarctica's ice sheet? It's just a blink of an an eye in time. The reason they don't use the term global warming anymore is because it isn't and wasn't warming. So lets not give up our uninformed speculations (which means without facts) and come up with a whole bunch more speculation and call it climate change. Nothing new there, that's the way the world works we just don't know why. For example:Reply
What caused the ice ages and subsequent melting, repeated multiple times? To cause an ice age what was the source of the enormous heat required? Yes, I wrote heat. Where did the heat come from to evaporate multi cubic miles of ocean water to then snow heavily on land. Paradoxically, to make an ice age requires a huge amount of heat because you cannot evaporate enough water from a cold ocean to make miles thick ice. Northern Canada is cold enough now for an ice age if it snowed. Subsequently, many thousands of years later we need a large amount of excess heat to melt the ice. Where did that come from? Since this just does not figure we obviously don't understand it. If we don't understand ice ages, which actually happened, how can we claim to understand "climate change" which has not happened. I therefore assume our understanding of the role of minute quantities of CO2 in the atmosphere is equally flawed. Which means we do not understand climate but we tax people anyway (who can't do anything about it but freeze) for using carbon bearing fuel. In Ontario Canada I am paying a carbon tax on the oil I use to heat my house and domestic hot water. I can't switch to a low or no carbon fuel (what would that be?) and the cost of heating with electricity here is murderous. We have to pay for the huge mistake of putting up thousands of windmills, the power from which costs about 10x that of our nuclear. Stupid! Somebody's ripping us off big time here, twice ---- first the fake science then the stupid politicians who believe it.
It is clear that you have a few misconceptions concerning global warming (and no it has not changed to climate change - climate change is a consequence of global warming in a cause effect relationship. The term climate change was popularized by the Bush administration). First, if global temperatures are constant, then the Antarctic Ice sheet remains constant. Since we have 13 years of direct measurements of ice mass showing increasing loss, this is strong evidence that temperatures in Antarctica are increasing (although there is some increase in air temperature, most of the extra heat is comes in from the adjacent Antarctic Ocean). Yes, Antarctica has lost and gained mass before but there is no indication it has done so since the last glacial period of the current ice age.Reply
Interesting that it requires heat for an ice age - energy is required for evaporation. In fact, while lots of heat is required, there certainly is a lot less heat during to create and during a glacial period. It is fairly easy to figure this out as a glacial period is difficult to trigger without a significant decrease in solar input (about a 20-30% drop in incoming solar radiation is required).
Northern Canada is not cold enough to accumulate snowfall enough to lead to an ice age. This has not been the case in the last 10,000 years when summer heat is sufficient to remove any snow accumulated during the winter months. However, over the last 40 years, the increased heat has led to significant continental ice losses and also explains why the permafrost zone has moved significantly northwards.
Finally, I am somewhat curious why you write why we don't understand global warming (climate change) when it is more truthful to suggest that 'you' don't understand global warming. Simple enough to ask if you don't understand something and seems less appropriate because you don't know something to claim it is fake science.