Ice loss from Antarctica has sextupled since the 1970s, new research finds
An alarming study shows massive East Antarctic ice sheet already is a significant contributor to sea-level rise
Chris Mooney and Brady Dennis
January 14 at 3:00 PM (Washington Post)
Antarctic glaciers have been melting at an accelerating pace over the past four decades thanks to an influx of warm ocean water — a startling new finding that researchers say could mean sea levels are poised to rise more quickly than predicted in coming decades.
The Antarctic lost 40 billion tons of melting ice to the ocean each year from 1979 to 1989. That figure rose to 252 billion tons lost per year beginning in 2009, according to a study published Monday in the Proceedings of the National Academy of Sciences. That means the region is losing six times as much ice as it was four decades ago, an unprecedented pace in the era of modern measurements. (It takes about 360 billion tons of ice to produce one millimeter of global sea-level rise.)
“I don’t want to be alarmist,” said Eric Rignot, an Earth-systems scientist for the University of California at Irvine and NASA who led the work. But he said the weaknesses that researchers have detected in East Antarctica — home to the largest ice sheet on the planet — deserve deeper study.
“The places undergoing changes in Antarctica are not limited to just a couple places,” Rignot said. “They seem to be more extensive than what we thought. That, to me, seems to be reason for concern.”
The findings are the latest sign that the world could face catastrophic consequences if climate change continues unabated. In addition to more-frequent droughts, heat waves, severe storms and other extreme weather that could come with a continually warming Earth, scientists already have predicted that seas could rise nearly three feet globally by 2100 if the world does not sharply decrease its carbon output. But in recent years, there has been growing concern that the Antarctic could push that even higher.
That kind of sea-level rise would result in the inundation of island communities around the globe, devastating wildlife habitats and threatening drinking-water supplies. Global sea levels have already risen seven to eight inches since 1900.
The full drivel here
Why do I call it “drivel”? Three reasons:
1. Anything Chris Mooney writes about climate is automatically in that category, because he can’t separate his fear of doom from his writing.
2. The math doesn’t work in the context of the subheadline. Alarming? Read on.
3. Data back to 1972…where?
First, let’s get some data. Wikipedia, while biased towards alarmism in this reference, at least has the basic data.
It covers an area of almost 14 million square kilometres (5.4 million square miles) and contains 26.5 million cubic kilometres (6,400,000 cubic miles) of ice.A cubic kilometer of ice weighs approximately one metric gigaton, meaning that the ice sheet weighs 26,500,000 gigatons.
Now for the math.
So, if the Antarctic ice sheet weighs 26,500,000 gigatonnes or 26500000000000000 tonnes
252 billion tonnes is 252 gigatonnes
Really simple math says: 252gt/26,500,000gt x 100 = 9.509433962264151e-4 or 0.00095% change per year
But this is such a tiny loss in comparison to the total mass of the ice sheet, it’s microscopic…statistically insignificant.
In the email thread that preceded this story (h/t to Marc Morano) I asked people to check my work. Willis Eschenbach responded, corrected an extra zero, and pointed this out:
Thanks, Anthony. One small issue. You’ve got an extra zero in your percentage, should be 0.00095% per year loss.
Which means that the last ice will melt in the year 3079 …
I would also note that 250 billion tonnes of ice is 250 billion cubic meters. Spread out over the ocean, that adds about 0.7 mm/year to the sea level … that’s about 3 inches (7 cm) per century.
As you said … microscopic.
Paul Homewood noted in the email thread:
Ice losses from Antarctica have tripled since 2012, increasing global sea levels by 0.12 inch (3 millimeters) in that timeframe alone, according to a major new international climate assessment funded by NASA and ESA (European Space Agency).
0.5mm per year.
Not a lot to worry about.
“They attribute the threefold increase in ice loss from the continent since 2012 to a combination of increased rates of ice melt in West Antarctica and the Antarctic Peninsula, and reduced growth of the East Antarctic ice sheet.”
Translation: The volcano riddled West/Peninsula is melting bit more and the Eastern Sheet is growing a little less than usual.
Paul Homewood adds on his website:
Firstly, according to NASA’s own press release, the study only looks at data since 1992. The Mail’s headline (Taken from the Washington Post – Anthony) that “Antarctica is losing SIX TIMES more ice a year than it was in the 1970s “ is totally fake, as there is no data for the 1970s. Any estimates of ice loss in the 1970s and 80s are pure guesswork, and have never been part of this NASA IMBIE study, or previous ones.
Secondly, the period since 1992 is a ridiculously short period on which to base any meaningful conclusions at all. Changes over the period may well be due to natural, short term fluctuations, for instance ocean cycles. We know, as the NASA study states, that ice loss in West Antarctica is mainly due to the inflow of warmer seas.
The eruption of Pinatubo in 1991 is another factor. Global temperatures fell during the next five years, and may well have slowed down ice melt.
Either way, Pinkstone’s claim that the ice loss is due to global warming is fake. It is a change in ocean current that is responsible, and nothing to do with global warming.
Then there is his pathetic claim that “Antarctica is shedding ice at a staggering rate”. Alarmist scientists, and gullible reporters, love to quote impressive sounding numbers, like 252 gigatons a year. In fact, as NASA point out, the effect on sea level rise since 1992 is a mere 7.6mm, equivalent to 30mm/century.
Given that global sea levels have risen no faster since 1992 than they did in the mid 20thC, there is no evidence that Antarctica is losing ice any faster than then. To call it staggering is infantile.
NASA also reckon that ice losses from Antarctica between 2012 and 2017 increased sea levels by 3mm, equivalent to 60mm/century. Again hardly a scary figure. But again we must be very careful about drawing conclusions from such a short period of time. Since 2012, we have had a record 2-year long El Nino. What effect has this had?
But back to that previous NASA study, carried out by Jay Zwally in 2015, which found:
A new NASA study says that an increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers.
The research challenges the conclusions of other studies, including the Intergovernmental Panel on Climate Change’s (IPCC) 2013 report, which says that Antarctica is overall losing land ice.
According to the new analysis of satellite data, the Antarctic ice sheet showed a net gain of 112 billion tons of ice a year from 1992 to 2001. That net gain slowed to 82 billion tons of ice per year between 2003 and 2008.
Far from losing ice, as the new study thinks, Zwally’s 2015 analysis found the opposite, that the ice sheet was growing.
OK, Zwally’s data only went up to 2008, but there are still huge differences. Whereas Zwally estimates ice gain of between 82 and 112 billion tonnes a year between 1992 and 2008, the new effort guesses at a loss of 83 billion tonnes a year.
It is worth pointing out that Zwally’s comment about the IPCC 2013 report refers to the 2012 IMBIE report, which was the forerunner to the new study, the 2018 IMBIE.
Quite simply, nobody has the faintest idea whether the ice cap is growing or shrinking, never mind by how much, as the error margins and uncertainties are so huge.
The best guide to such matters comes from tide gauges around the world. And these continue to show that sea levels are rising no faster then mid 20thC, and at a rate of around 8 inches per century.