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Antarctica is dropping ice mass to the ocean, contributing to world sea degree rise. However a preferred video misrepresented work centered on Antarctic ice cabinets — which float within the sea on the edges of the continent — to incorrectly recommend that “it’s unclear if Antarctica is dropping any ice on steadiness.”
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The Antarctic ice sheet is an unlimited mass of ice, accumulated over millennia through snowfall, that sits atop bedrock, protecting nearly all of Antarctica. Because the ice spreads outward and meets the ocean, a few of it begins to drift. These floating ice platforms, which surround about three-quarters of Antarctica, are referred to as ice cabinets.
Antarctic land ice loss into the ocean is an increasingly important contributor to world sea level rise. In distinction, ice shelf loss doesn’t directly trigger sea degree rise, because the ice is already floating within the ocean and displacing water. Nevertheless, ice shelf modifications can contribute to land ice loss, as ice cabinets in some areas buttress land ice and gradual its descent into the ocean.
A well-liked video from the Heartland Institute — which has a protracted history of casting doubt on local weather science — minimized the importance of Antarctic ice loss after which questioned whether or not it’s occurring in any respect. “The reality is, it’s unclear if Antarctica is dropping any ice on steadiness or if it’s presently experiencing a web achieve,” the video’s narrator inaccurately mentioned, citing two scientific papers.
“The assertion is fake,” Chad Greene, a glaciologist at NASA’s Jet Propulsion Laboratory, instructed us in an e mail. “Antarctica has been dropping sea ice, grounded ice, and floating ice shelf mass over the previous few a long time. Satellite tv for pc evaluation from NASA teams present traits of ice loss, and the identical traits have been reported by unbiased analysis teams from around the globe.”
We reached out to the Heartland Institute with questions concerning the video however haven’t gotten a reply. The video was initially posted on Facebook and YouTube however is now not accessible on Fb.
The primary paper talked about within the video to again up the declare is a 2015 study by NASA researchers. They discovered that from 1992 to 2001 and 2003 to 2008, Antarctica gained ice mass.
However different research disagree with the discovering that Antarctica was gaining ice, and a NASA press release concerning the research now comprises a message saying, “The findings reported right here battle with over a decade of different measurements, together with earlier NASA research.”
“[M]ore current work exhibits clearly that on steadiness Antarctica is dropping mass,” Jonathan Kingslake, who research ice sheet evolution at Columbia Local weather Faculty’s Lamont-Doherty Earth Observatory, instructed us in an e mail.
In accordance with measurements from NASA satellites, since 2002 Antarctica has been dropping a median of 140 billion metric tons of ice mass per 12 months.
The Heartland Institute video went on to incorrectly state {that a} 2023 paper information from 2009 to 2019 confirmed the 2015 NASA findings. Nevertheless, that paper checked out Antarctic ice shelf space — the floating ice on the edges of the continent, as we defined — and never ice sheet mass general. Saying that the 2023 paper confirmed the sooner NASA findings “is completely deceptive,” Kingslake mentioned.
Moreover, information from an extended time-frame does present lack of Antarctic ice shelf space, Greene mentioned.
The Sixth Evaluation Report from the Intergovernmental Panel on Local weather Change — the most recent report from this United Nations physique — discovered that each the Greenland and the Antarctic ice sheets have been “dropping mass since a minimum of 1990, with the best loss charge throughout 2010–2019” — a press release made with “excessive confidence.” And the ice sheet mass loss is anticipated to proceed.
Antarctic Ice Loss Is Consequential
Earlier within the Heartland Institute video, the narrator did acknowledge Antarctic ice loss however minimized its significance.
“The media claims that Antarctica is dropping ice six or extra instances quicker than it was a couple of a long time in the past,” the video mentioned. “However Antarctica was barely dropping ice again then and it nonetheless is barely dropping ice in comparison with its general ice mass. Some satellite tv for pc measurements estimate that the full ice loss annually from Antarctica is 3/10,000 of 1% of the continent’s ice mass. That’s not a lot.”
Media retailers have reported, primarily based on numerous research, that the Antarctic ice sheet as of the 2010s was melting six instances quicker than within the Nineteen Eighties, or that the Antarctic and Greenland ice sheets combined had been losing ice six instances quicker within the 2010s than within the Nineties.
It’s appropriate that Antarctica “is barely dropping ice in comparison with its general ice mass,” because the video mentioned, on condition that Antarctica’s whole ice mass could be very giant, Helen Amanda Fricker, a professor at UC San Diego’s Scripps Establishment of Oceanography, instructed us in a written response to our questions. However “I might flip this round and say that even a small % of a big quantity is just not inconsequential,” she mentioned. The Antarctic ice sheet comprises sufficient ice — if all of it melted — to lift sea degree by 57 meters, or 187 ft, she mentioned.
Oceanographer Laurence Padman, president and senior scientist at Earth and Area Analysis, a nonprofit analysis institute, instructed us that he couldn’t argue with the fraction of ice misplaced given within the video, primarily based on tough calculations and given variation and uncertainties in annual ice loss. However “the essential quantity is the ocean degree rise, not the fraction of the Antarctic ice sheet that’s misplaced,” he mentioned in a written response to our questions.
As of 2018, the worldwide common sea degree had risen by 7 to fifteen centimeters (nearly 3 to six inches) since 1971, in line with the most recent IPCC report, and was projected to rise by 10 to 25 centimeters (about 4 to 10 inches) extra by 2050, even when greenhouse fuel emissions are diminished. Melting of the Antarctic ice sheet brought on 7% of sea degree rise between 1971 and 2018, however its contribution to sea degree rise has elevated and can proceed to extend.
Since 2016, the Antarctic ice sheet has been chargeable for 14% of sea degree rise, in line with the IPCC report. In a low-emissions situation, the Antarctic ice sheet might contribute to greater than 20% of sea degree rise by 2100, in line with a graphic within the report’s FAQ part.
Lizz Ultee, a glaciologist at Middlebury School, defined that sea degree rise is driven by two foremost processes: ocean water growth because it will get hotter and melting of ice into the ocean.
Mountain glaciers soften extra shortly as a consequence of warming temperatures than ice sheets as a result of mountain glaciers are smaller, Ultee defined. However the Greenland and Antarctic ice sheets are taking part in an increasing function in sea degree rise.
At the moment, Greenland, which has a smaller ice sheet than Antarctica, is dropping ice mass at a faster charge, however in the long run, Antarctica “has probably the most potential to contribute to very giant sea degree modifications,” Ultee mentioned.
Antarctic ice sheet loss will in all probability result in as much as about 0.3 meters, or almost 1 foot, of sea degree rise by 2100, she mentioned, and whole sea degree rise could be about half a meter to a meter (1.6 to three.3 ft) by that point. Even when people had been to cease contributing to local weather change by 2100, she mentioned, Antarctica would proceed to lose ice mass and contribute to sea degree rise for hundreds of years.
A few meter of sea degree rise in 2100 would flood the properties of about 4 million people within the U.S., Ultee mentioned, an estimate that doesn’t embody individuals who could be in danger from larger storm surges or extra frequent tidal flooding, or who could be reduce off from important companies.
The Japanese Gulf of Mexico — from the Mississippi Delta to Florida — has already skilled a few of the quickest charges of native sea degree rise within the U.S., according to the Nationwide Oceanic and Atmospheric Administration.
The Vital Position of Ice Cabinets
As we’ve mentioned, the Heartland Institute video additionally misrepresented information on ice cabinets, incorrectly claiming a 2023 paper confirmed that the Antarctic ice sheet is gaining mass.
The 2023 paper, printed within the Cryosphere, used satellite tv for pc information to investigate the world of Antarctic ice cabinets between 2009 and 2019, discovering that 16 ice cabinets grew in space and 18 acquired smaller. This translated to a web achieve of 5,305 sq. kilometers in whole ice shelf space, representing a rise of 0.4%.
However “this paper is about Antarctic ice cabinets, that are solely the floating parts of the ice in Antarctica,” Ultee mentioned. Ice cabinets are made up of ice that has flowed from the continent outward to the ocean and is floating. (Sea ice, which varieties seasonally from the ocean and in addition floats, is distinct from ice cabinets.)
The work “doesn’t assist the assertion that the Antarctic ice sheet is just not dropping mass,” Ultee mentioned.
Padman additionally mentioned that the Cryosphere paper checked out one particular time interval that doesn’t symbolize the complete historical past of Antarctic ice shelf loss. Prior work, published in Nature in 2022, confirmed that Antarctic ice cabinets misplaced 35,000 sq. kilometers of space between 1997 and 2004. The Cryosphere paper confirmed the ice cabinets regaining “solely about 15% of the sooner loss,” he mentioned.
Greene, the NASA scientist, co-authored the Nature paper. In that research, “we used an extended, 24 12 months baseline and located overwhelming lack of ice shelf space since 1997,” he mentioned. “We then regarded on the calving historical past of the largest ice cabinets and located that they’re all on observe for main calving occasions within the subsequent 10 or 15 years … which means Antarctica as an entire is dropping ice shelf mass general.” (Ice shelf calving happens when chunks of ice break off into the ocean.)
Moreover, ice shelf loss in particular areas is important and not directly influences sea degree rise, consultants instructed us.
“Ice cabinets don’t instantly contribute to sea degree rise once they soften however somewhat, they act like buttresses to glaciers, preserving the ice from merely sliding into the ocean,” Greene mentioned.
Padman added that “some areas of ice cabinets have an effect on ‘buttressing’ of grounded ice, whereas different areas don’t.” The ice cabinets proven to be dropping ice within the Cryosphere paper — many in West Antarctica — are typically extra essential for buttressing the ice sheet than the ice cabinets which can be gaining ice.
“Even when East Antarctic ice cabinets are gaining space and the West Antarctic is dropping space, we nonetheless actually care concerning the West Antarctic ice shelf space,” Ultee mentioned.
Editor’s be aware: SciCheck’s articles offering correct well being info and correcting well being misinformation are made attainable by a grant from the Robert Wooden Johnson Basis. The muse has no control over FactCheck.org’s editorial selections, and the views expressed in our articles don’t essentially mirror the views of the inspiration.
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