Tamino is writing about this subject, too. That entirely makes complete sense as it is the biggest geophysical and environmental story out there right now. I’ve included an update at this post’s end discussing the possible economic impacts.

It’s been known for a couple of years that the West Antarctic ice sheet was destabilizing and that this would result in appreciable sea-level rise. What wasn’t known was how widespread this was in Anarctica, and how fast this might proceed.

Well, we’re beginning to find out, and the news isn’t good.

Data below from “Mass balance of the Antarctic ice sheet from 1992 to 2017”, The IMBIE Team, Nature, 2018, 558, 219-222.

Abstract

The Antarctic Ice Sheet is an important indicator of climate change and driver of sea-level rise. Here we combine satellite observations of its changing volume, flow and gravitational attraction with modelling of its surface mass balance to show that it lost 2,720 ± 1,390 billion tonnes of ice between 1992 and 2017, which corresponds to an increase in mean sea level of 7.6 ± 3.9 millimetres (errors are one standard deviation). Over this period, ocean-driven melting has caused rates of ice loss from West Antarctica to increase from 53 ± 29 billion to 159 ± 26 billion tonnes per year; ice-shelf collapse has increased the rate of ice loss from the Antarctic Peninsula from 7 ± 13 billion to 33 ± 16 billion tonnes per year. We find large variations in and among model estimates of surface mass balance and glacial isostatic adjustment for East Antarctica, with its average rate of mass gain over the period 1992–2017 (5 ± 46 billion tonnes per year) being the least certain.

For every centimeter [of sea-level rise] from West Antarctica, Boston feels one and a quarter centimeters. And that extends down the East Coast.

— Professor Robert M DeConto, University of Massachusetts, Amherst, Geosciences, as quoted in The Atlantic, 13^th June 2018, “After decades of losing ice, Antarctica is now hemorrhaging it”.

See also

S. Kruel, “The impacts of sea-level rise on tidal flooding in Boston, Massachusetts”, Journal of Coastal Research, 2016, 32(6), 1302-1309.

which I have already written about here.

It is important to understand that it is too late to stop this part of the effects of climate change: Boston and coasts will flood. We can hope that by the world cutting back on emissions it might slow. But reversing it is out of the question. And, to the degree the world is not keeping on schedule, even the slowing looks out of reach.

But, seriously, it’s unrealistic to think anything else. We have important groups of people (like those who elect Congress and the President) who don’t consider these risks serious, even doubt them, or think that Archangel Michael will come riding down on a big white horse and save us collectively because of Manifest Destiny or some other pious rubbish.

Unfortunately, we did not fund the research to ascertain how fast this could go until late, and we’ve done essentially nothing so far on a serious scale to try to stop it, setting the impossible condition of having to maintain an American economic boom. That might prove to be the most expensive economic expansion the world has ever seen.

Update, 2018-06-17

Beyond the geophysical impact of impending ice sheet collapse, there’s the economic one: If insurance prices don’t head upwards quickly, and real estate prices for expensive homes on the coasts don’t come under downward pressure, the only reason can be is that they expect the U.S. federal government to continue to fund their rebuilding through the Biggert-Waters Act (2012), the Homeowner Flood Insurance Affordability Act (2014), the Stafford isaster Relief and Emergency Assistance Act (1988), the Disaster Mitigation Act (2000), and the Pets Evacuation and Transportation Standards Act (2006). The wisdom of continuing these in the face of increasing storm costs is being questioned with greater ferocity. (See also.) It’s not difficult to see why:

And, courtesy of the New York Times:

And, courtesy of NOAA:

While some critics (e.g., Pielke, et al, “Normalized hurricane damage in the United States — 1900-2005”) have claimed the increases in losses is because there is more expensive property being damaged by otherwise ordinary storms, correction of losses by the Consumer Price Index (CPI) controls for some of that, and the rates of inflation in damage exceed rates of even the most appreciating real estate values. Moreover, if that’s the reason for the losses, nothing is being done to discourage the practice. Sure, inflation might not be able to be controlled, but (a) it has been very low in recent years and, (b), the CPI-adjusted values from NOAA show that’s not the explanation. The amount loss to disasters is climbing and the claim that’s all it’s about is disingenuous at best.

At some point the federal government will stop or significantly limit and curtail bailouts of rebuilds, like the affluent homes on Alabama’s Dauphin Island. At that point the value of coastal real estate will crest, and it may possibly plummet: A classic Minsky moment. It would be inadvisable to own coastal real estimate when that happens, particularly in towns like Falmouth, Massachusetts. See an article from Forbes which reports climate change is already depressing coastal real estate values by 7%.