Worse than previously thought: Arctic has lost 95% of its oldest, thickest ice and now the formerly stable East Antarctica is melting too
New data shows that over the past three decades, the Arctic has lost 95 percent of its oldest, thickest ice. (Photo: Christopher Michel/Flickr/cc)
As the Trump administration tries to undermine the COP 24 climate talks in Poland, new U.S. government data shows that ice melt at both of the planet’s poles—driven by rising air and ocean temperatures resulting from human-caused global warming—is worse than previously thought.
“The Arctic is an indication of what’s coming to the rest of the globe.”
—Walt Meier, NSCDI
The latest annual Arctic Report Card from National Oceanic and Atmospheric Administration (NOAA) found that over the past three decades, a “stunning” 95 percent of northern region’s the oldest, thickest ice has disappeared.
As the Washington Post reported:
The finding suggests that the sea at the top of the world has already morphed into a new and very different state, with major implications not only for creatures such as walruses and polar bears but, in the long term, perhaps for the pace of global warming itself.
The oldest ice can be thought of as a kind of glue that holds the Arctic together and, through its relative permanence, helps keep the Arctic cold even in long summers…
If the Arctic begins to experience entirely ice-free summers, scientists say, the planet will warm even more, as the dark ocean water absorbs large amounts of solar heating that used to be deflected by the cover of ice.
“The Arctic is an indication of what’s coming to the rest of the globe,” noted Walt Meier, a sea ice expert at the National Snow and Ice Data Center (NSIDC). And while the timeline is uncertain, the region appears on-track to experience an ice-free summer.
“In the Arctic Ocean, a difference of 2 degrees can be huge. If it goes from 31 Fahrenheit to 33 Fahrenheit, you’re going from ice skating to swimming,” Meier told the Post. “Looking down from the North Pole from above, for all intents and purposes, you’re going to see a blue Arctic Ocean.”
If ice-free summers become the Arctic’s new normal, it would be an “unmitigated disaster,” concluded Veerabhadran Ramanathan, a climate expert at the Scripps Institution of Oceanography. Such conditions, he warned, could add another half-degree Celsius (0.9 degrees Fahrenheit) to the already-alarming rates of global temperature rise.
Meanwhile, at the world’s southern pole, as the Guardian reported, NASA researchers have discovered that “a group of glaciers spanning an eighth of the East Antarctica coastline are being melted by the warming seas.” This region, the newspaper noted, “stores a vast amount of ice, which, if lost, would in the long-term raise global sea level by tens of meters and drown coastal settlements around the world.”
East Antarctica is relatively unstudied compared with West Antarctica, where “utterly terrifying” findings have fueled demands for urgent action worldwide to dramatically cut planet-warming emissions. (Editor’s note: Ice scientist Eric Rignot has said we must return to the temperatures of the 1970s; i.e., get off of fossil fuels pronto and back to longterm CO2 levels to reattain stability). For this study, NASA researchers used satellites to analyze ice movements and heights, and measured ocean temperature over time by tagging seals.
The ice retreat they saw, “doesn’t seem random, it looks systematic,” explained NASA’s Alex Gardner. “That hints at underlying ocean influences that have been incredibly strong in West Antarctica.” While the observations have experts worried, Gardner said they indicate a need for more research to determine “whether these glaciers will enter a phase of rapid retreat or stabilize.”
BBC: NASA says it has detected the first signs of significant melting in a swathe of glaciers in East Antarctica.
The region has long been considered stable and unaffected by some of the more dramatic changes occurring elsewhere on the continent.
But satellites have now shown that ice streams running into the ocean along one-eighth of the eastern coastline have thinned and sped up.
If this trend continues, it has consequences for future sea levels.
There is enough ice in the drainage basins in this sector of Antarctica to raise the height of the global oceans by 28m – if it were all to melt out.
“That’s the water equivalent to four Greenlands of ice,” said Catherine Walker from NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
The glaciologist has been detailing her work here at the Fall Meeting of the American Geophysical Union (AGU).
Image copyrightNASADr Walker has been making the most of a new initiative at the agency to process huge numbers of satellite images to get a more resolved and more timely view of what is happening in East Antarctica.
Previously, scientists had been aware that the region’s Totten Glacier was experiencing melting, most probably as a result of its terminus being affronted by warm water coming up from the deep ocean. Pretty much everything else in that part of the continent was considered stagnant, however.
The new satellite elevation and velocity maps change this view. They make it clear that nearby glaciers to Totten are also starting to respond in a similar way.
Marked change is detected in the Vincennes Bay and Denman areas just to the west, and in Porpoise Bay and on the George VI coast to the east.
Vincennes Bay – which includes the Underwood, Bond, Adams, and Vanderford glaciers – has the most pronounced loss in ice mass. Elevation is dropping at five times the rate it was in 2008 – with a total fall in height over the period of almost 3m.
“They’ve also sped up about 3% from their 2008 velocity, which sounds small but is significant enough to change the flux coming out of those glaciers because they are very deep,” said Dr Walker.
Image copyrightNASAOnce again the melting culprit is likely to be warm water that is being pulled up from the deep by shifting sea-ice and wind patterns in the region.
The changes that are occurring are still quite subtle, and they are only really discernible because of the new automated computer tools that will search through the millions of satellite images taken of Antarctica.
NASA is about to widen access to these tools through a project called Inter-mission Time Series of Land Ice Velocity and Elevation, or ITS_LIVE.
“I think we can anticipate that over the next five to 10 years, we’re going to have a lot of observationally driven discoveries, such as what Catherine is making, because of the new data that’s coming online,” said Alex Gardner, a glaciologist (cryospheric scientist)