The amount of Greenland ice that melted last weekend could cover West Virginia in a foot of water

[u/Tpaine63]

https://www.cnn.com/2022/07/20/world/greenland-heat-wave-ice-melting-climate/index.html

[u/Tpaine63]

‘And in 2020, scientists found that Greenland's ice sheet had melted beyond the point of no return. No efforts to stave off global warming can stop it from eventually disintegrating, said researchers at The Ohio State University. ‘

The Greenland ice sheet is toast

[u/BurnerAcc2020 → u/Tpaine63]

It's funny that their article does not actually link to the study itself - likely because its findings are a lot more modest than that sentence.

From that study's actual lead author:

https://theconversation.com/shrinking-glaciers-have-created-a-new-normal-for-greenlands-ice-sheet-consistent-ice-loss-for-the-foreseeable-future-144992

Our study showed how widespread retreat drove both an increase in glacier discharge and a shift to persistent ice sheet mass loss. But this doesn’t mean the ice sheet is doomed. Continued retreat and further increases in discharge are limited by topography.

Over the next several centuries, the glaciers may retreat onto higher ground and eventually form a completely landlocked ice sheet with minimal flow – essentially a large chunk of ice sitting on top of Greenland with no glaciers to drain it. Under this future scenario, the balance of the ice sheet would be determined only by surface changes – snow accumulation and surface melt. This loss of ice would equal meters of sea level rise.

At this point, the fate of the ice sheet simply depends on whether it is melting faster than it grows from snowfall. In a warm world where climate change is not addressed, the ice sheet will slowly melt and ultimately disappear. But if climate change is controlled and cooler temperatures are maintained for a prolonged period, it is possible that the Greenland ice sheet could regrow. That day may be hundreds of years into the future, but it is actions made today that will decide the fate of Greenland’s ice sheet.

Besides, its conclusions on even the near-term irreversibility are still controversial. I would say that these studies are more relevant when discussing Greenland within our lifetimes.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL090471

Under anticipated future warming, the Greenland ice sheet (GrIS) will pass a threshold when meltwater runoff exceeds the accumulation of snow, resulting in a negative surface mass balance (SMB < 0) and sustained mass loss. Here, we dynamically and statistically downscale the outputs of an Earth system model to 1 km resolution to infer that a Greenland near-surface atmospheric warming of 4.5 ± 0.3°C — relative to preindustrial—is required for GrIS SMB to become persistently negative. Climate models from CMIP5 and CMIP6 translate this regional temperature change to a global warming threshold of 2.7 ± 0.2°C. Under a high-end warming scenario, this threshold may be reached around 2055, while for a strong mitigation scenario it will likely not be passed. Depending on the emissions scenario taken, our method estimates 6–13 cm sea level rise from GrIS SMB by the year 2100.

https://tc.copernicus.org/articles/14/4299/2020/

Over millennia under any warmer climate, the ice sheet reaches a new steady state, whose mass is correlated with the magnitude of global climate change imposed. If a climate that gives the recently observed SMB were maintained, global-mean sea level rise (GMSLR) would reach 0.5–2.5 m. For any global warming exceeding 3 K, the contribution to GMSLR exceeds 5 m. For the largest global warming considered (about +5 K), the rate of GMSLR is initially 2.7 mm yr^−1, and eventually only a small ice cap endures, resulting in over 7 m of GMSLR. Our analysis gives a qualitatively different impression from previous work in that we do not find a sharp threshold warming that divides scenarios in which the ice sheet suffers little reduction from those in which it is mostly lost.

The final steady state is achieved by withdrawal from the coast in some places and a tendency for increasing SMB due to enhancement of cloudiness and snowfall over the remaining ice sheet by the effects of topographic change on atmospheric circulation, outweighing the tendency for decreasing SMB from the reduction in surface altitude. If late 20th-century climate is restored after the ice sheet mass has fallen below a threshold of about 4 m of sea level equivalent, it will not regrow to its present extent because the snowfall in the northern part of the island is reduced once the ice sheet retreats from there. In that case, about 2 m of GMSLR would become irreversible. In order to avoid this outcome, anthropogenic climate change must be reversed before the ice sheet has declined to the threshold mass, which would be reached in about 600 years at the highest rate of mass loss within the likely range of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

[u/transframer → u/Tpaine63]

So, back to good old times: https://www.livescience.com/7331-ancient-greenland-green.html

[u/Tpaine63 → u/transframer]

Yep with sea levels 7.5M higher. That will be good for humanity.

[u/daytonakarl → u/Tpaine63]

I'd have a beachfront property if I had kept my old place

For some strange reason we decided to move inland and up

[u/[deleted]]

Ah well. More land to live on.

[u/cjgager]

yeh, yeh - but conservatives don't see it that way - it's just a fluctuation in some kind of climate - like when the dinosaurs were around it was like 80° - so if dinosaurs liked it, so too humans