New research on ice cliff instability and the past speed of calving from Pine Island Glacier during warming is sobering. Fossil fuel subsidies almost guarantee an 11 foot sea level rise by 2100.
... this could play out in a mere 20 to 50 years ...
Instead of a three-foot increase in ocean levels by the end of the century, six feet was more likely, according to DeConto and Pollard’s findings. But if carbon emissions continue to track on something resembling a worst-case scenario, the full 11 feet of ice locked in West Antarctica might be freed up, ...
... in the worst case, if we don’t do the work, pretty much all coastal cities and low lying regions will be inundated starting now and running over a rather short multi decade period (2020 to 2300).
What Robert DeConto did, and what has apparently scared Eric Holthaus so much, was apply a computer model based on observations of Jakobshavn ice sheet collapse to these larger Antarctic ice masses.
NOAA's report in January included an extreme sea-level rise forecast of 10 to 12 feet of sea-level rise by 2100 around the U.S., compared to the previous estimate of about 8 feet.
Climate Central then created images that showed what such extreme water rises would look like.
In New York City, for instance, an average high tide would be 2 feet higher than Hurricane Sandy’s flood level, covering an area inhabited by more than 800,000 residents.
[comment by Wili]
DeConto says that to construct their model, they took the collapse rate of Jakobshavn, cut it in half to be extra conservative, then applied it to Thwaites and Pine Island.
But there’s reason to think Thwaites and Pine Island could go even faster than Jakobshavn. [emphasis mine]
Will Denayer at Flassbeck Economics International points out that while 6 feet of sea level rise would destroy several megacities and create 12 million climate refugees, an 11 foot rise would put so many cities and so much land underwater that political institutions would break down.
Research investigating thousands of marks on the Antarctic seafloor, caused by icebergs breaking off of glaciers around 12 thousand years ago in Pine Island Bay found that rapid and sustained ice sheet retreat didn’t take thousands of years or even several centuries.
Today, as global climate continues to warm, rapid and sustained retreat may be close to happening all over and could trigger runaway ice retreat into the interior of the continent, which in turn would cause sea levels to rise much faster than currently projected. … the message is that it went quick …
... the bottom line: the melt will go fast and we are not preparing. Incredibly, we continue to race towards disaster. Globally, our emissions are rising. Temperature is rising…
Radically insane as it is, the world continues to slash out enormous subsidies for fossil fuel companies.
... nice intentions take nothing away from the essential fact that the G20 countries subsidise fossil fuels by over $ 1.000 per citizen – a figure from the IMF (see here). Globally, fossil fuels are subsidised by $ 10 million every minute. In 2015, the subsidies to the fossil fuel companies were bigger than the health spending of all governments combined (see here), the total amounts to $ 5.3 trillion a year.