Red
Well-Known Member
Check this out. That statement does not appear to be true at all. How can anyone refute this latest study? How?
https://www.inverse.com/article/55134-greenland-ice-sheet-climate-change
Previous research demonstrated that, in 2012, the annual ice loss was already nearly four times the rate it was in 2003. What Rignot and his team found in the new study was alarming: The Greenland Ice Sheet has undergone rapid and irreversible change, and they can pinpoint exactly when the climate of the planet took a terrible turn.
“Going from a 20-year-long record to a 40-year-long record shows us a transition from a climate dominated by natural variability to a climate dominated by climate warming from human emissions of greenhouse gases,” Rignot says. “Over that time period, the mass loss increased sixfold.”
To come to this conclusion, they evaluated 46 years worth of data documenting the ice velocity, thickness, and surface elevation of 260 glacial drainage basins. They plugged this data into advanced atmospheric climate models that allowed them to estimate rates of ice accumulation, sublimation, melting at the glacier surface, and the velocity and thickness of ice discharge into the ocean.
The data show that in the ‘70s, the Greenland Ice Sheet gained an average of 47 gigatonnes of ice per year. But by the 1980s, it was losing an average of 50 gigatonnes of ice annually. Rignot explains that this is the time when “the climate of the planet drifted off its natural variability to become dominated by warming from human activity.”
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And here is the actual study. Note that over the 46 year period, the Jakobshavn glacier was actually one of the glaciers actually leading the ice loss:
https://www.pnas.org/content/early/2019/04/16/1904242116
In 2000–2012, half of the cumulative loss was from four glaciers, (i) Jakobshavn Isbræ, (ii) Kangerlussuaq, (iii) Køge Bugt, and (iv) Ikertivaq S (4), but, between 1972 and 2018, Ikertivaq S gained 26 ± 15 Gt. Over 46 years, the conclusions are different. The largest losses are from (i) Jakobshavn Isbræ (327 ± 40 Gt), (ii) Steenstrup-Dietrichson in NW (219 ± 11 Gt), (iii) Kangerlussuaq in CE (158 ± 51 Gt), (iv) Humboldt in NO (152 ± 7 Gt), (v) Midgårdgletscher in SE (138 ± 5 Gt), and (vi) Køge Bugt C in SE (119 ± 37 Gt), hence highlighting glaciers that are seldom mentioned in the literature. Steenstrup-Dietrichson, Humboldt, and Midgårdgletscher contributed to the mass loss during the entire period, versus only after year 2000 for Jakobshavn, Kangerlussuaq, and Helheimgletscher. This result illustrates the risk of summarizing the ice sheet loss on the basis of the fate of a few glaciers.
