PNAS - For Every Degree F In Global Temperature Increase, 4.2 Feet In Long-Term Sea Level Rise

[hatrack]

Measurements tell us that global average sea level is currently rising by about 1 inch per decade. But in an invisible shadow process, our long-term sea level rise commitment or "lock-in" — the sea level rise we don’t see now, but which carbon emissions and warming have locked in for later years — is growing 10 times faster, and this growth rate is accelerating.

An international team of scientists led by Anders Levermann recently published a study that found for every degree Fahrenheit of global warming due to carbon pollution, global average sea level will rise by about 4.2 feet in the long run. When multiplied by the current rate of carbon emissions, and the best estimate of global temperature sensitivity to pollution, this translates to a long-term sea level rise commitment that is now growing at about 1 foot per decade. We have two sea levels: the sea level of today, and the far higher sea level that is already being locked in for some distant tomorrow.

In a new paper published Monday in the Proceedings of the National Academy of Sciences (PNAS), I analyze the growth of the locked-in amount of sea level rise and other implications of Levermann and colleagues’ work. This article and its interactive map are based on this new PNAS paper, and they include extended results.

To begin with, it appears that the amount of carbon pollution to date has already locked in more than 4 feet of sea level rise past today’s levels. That is enough, at high tide, to submerge more than half of today’s population in 316 coastal cities and towns (home to 3.6 million) in the lower 48 states.

EDIT

http://www.climatecentral.org/news/sea-level-rise-locking-in-quickly-cities-threatened-16296

[phantom power]

1. I calculated that you get about 2ft/deg just from thermal expansion

totally ignoring any rise from ice melt

[LouisvilleDem]

3. That doesn't sound right

We've already had nearly 1 degree of warming over the last 100 years, but we haven't seen anything close to a 2 foot rise in sea levels over that period.

How did you come up with the 2ft/deg number?

[phantom power]

4. I should clarify, that was "a uniform 1 degree increase in temp of oceans"

The oceans temps haven't increased nearly as much as the atmosphere (and certainly not uniformly).

I did it by looking up the coefficient of thermal expansion for water, applying the expansion for +1C to the volume of the oceans, and then dividing by surface area.

[pscot]

2. Deltas are intensively farmed

and highly vulnerable to sea level rise. The UN Food and Agricultural Organization notes:

According to Nicholls and Leatherman (1995), a 1m sea-level rise would affect 6 million people in Egypt, with 12% to 15% of agricultural land lost, 13 million in Bangladesh, with 16% of national rice production lost, and 72 million in China and "tens of thousands" of hectares of agricultural land.

http://www.fao.org/nr/climpag/pub/eire0047_en.asp

Fortunately 6 billion people could live in Texas. I know it's true because I read it on the internet.
No worries, eh?

[stuntcat]

5. k & r