Earth’s Most Famous Climate Scientist Issues Bombshell Sea Level Warning

[GliderGuider]

Earth’s Most Famous Climate Scientist Issues Bombshell Sea Level Warning

The study—written by James Hansen, NASA’s former lead climate scientist, and 16 co-authors, many of whom are considered among the top in their fields—concludes that glaciers in Greenland and Antarctica will melt 10 times faster than previous consensus estimates, resulting in sea level rise of at least 10 feet in as little as 50 years. The study, which has not yet been peer reviewed, brings new importance to a feedback loop in the ocean near Antarctica that results in cooler freshwater from melting glaciers forcing warmer, saltier water underneath the ice sheets, speeding up the melting rate.

Hansen, who is known for being alarmist and also right, acknowledges that his study implies change far beyond previous consensus estimates. In a conference call with reporters, he said he hoped the new findings would be “substantially more persuasive than anything previously published.” I certainly find them to be.

Hansen’s study does not attempt to predict the precise timing of the feedback loop, only that it is “likely” to occur this century. The implications are mindboggling: In the study’s likely scenario, New York City—and every other coastal city on the planet—may only have a few more decades of habitability left. That dire prediction, in Hansen’s view, requires “emergency cooperation among nations.”

The science of ice melt rates is advancing so fast, scientists have generally been reluctant to put a number to what is essentially an unpredictable, non-linear response of ice sheets to a steadily warming ocean. With Hansen’s new study, that changes in a dramatic way. One of the study’s co-authors is Eric Rignot, whose own study last year found that glacial melt from West Antarctica now appears to be “unstoppable.” Chris Mooney, writing for Mother Jones, called that study a “holy shit” moment for the climate.

[phantom power]

1. who could have predicted... FTE

[XemaSab]

19. .

[BillZBubb]

2. A 10 foot sea rise in 50 years would be devastating.

The really sad thing is that it is too late to do anything about it.

[riversedge]

3. In S. Florida they are finally asking--Is it too late?

I read an article a few days ago asking this question. Many saying yes.--too last--prepare to move north---too late for seawalls or other mitigations-which might work for a while but not long term.

[Hortensis]

4. This is sickening, and scary. HOWEVER, last yearI found a study prepared by a commercial group that

estimated how much Florida land would be lost to sea rise (under previous estimates). I searched because we have a waterfront share in a MH coop on a river estuary just off Tampa Bay. At that time the estimate was hardly any, mostly here and there around the mouths of rivers. Oceanfront is very valuable land. Seawalls will be built. People who can't afford it will have to leave the coast for the interior, and people/businesses who can will move in.

That said, I'd really like to see a study based on this new scenario.

[tclambert]

11. Seawalls won't help much in Florida due to the porous bedrock.

The ocean can seep right under seawalls through the rock. Already some wells in Florida have turned briny because seawater has moved into the water table.

[OKIsItJustMe]

13. This map may help you

http://geology.com/sea-level-rise/florida.shtml

[ananda]

7. But for them this is not due to climate change ..

.. because those two words have been expunged from the Florida lexicon.

[OKIsItJustMe]

5. This seems in line with his work from 2007

https://iopscience.iop.org/1748-9326/2/2/024002/fulltext/

[font face=Serif]Environ. Res. Lett. 2 (April-June 2007) 024002
doi:10.1088/1748-9326/2/2/024002
[font size=5]Scientific reticence and sea level rise[/font]

[font size=4]J E Hansen

NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA[/font]

Email: [e-mail]

Received 23 March 2007
Accepted 3 May 2007
Published 24 May 2007

[font size=3]…

The IPCC (2007) midrange projection for sea level rise this century is 20–43 cm (8–17 inches) and its full range is 18–59 cm (7–23 inches). The IPCC notes that they are unable to evaluate possible dynamical responses of the ice sheets, and thus do not include any possible `rapid dynamical changes in ice flow'. Yet the provision of such specific numbers for sea level rise encourages a predictable public response that the projected sea level change is moderate, and smaller than in IPCC (2001). Indeed, there have been numerous media reports of `reduced' sea level rise predictions, and commentators have denigrated suggestions that business-as-usual greenhouse gas emissions may cause a sea level rise of the order of meters.

…

However, Hansen et al (2007) show that the typical ∼ 6 ky timescale for paleoclimate ice sheet disintegration reflects the half-width of the shortest of the weak orbital forcings that drive the climate change, not an inherent timescale of ice sheets for disintegration. Indeed, the paleoclimate record contains numerous examples of ice sheets yielding a sea level rise of several meters per century, with forcings smaller than that of the BAU scenario. The problem with the paleoclimate ice sheet models is that they do not generally contain the physics of ice streams, effects of surface melt descending through crevasses and lubricating basal flow, or realistic interactions with the ocean.

…

An important point is that the nonlinear response could easily run out of control, because of positive feedbacks and system inertias. Ocean warming and thus melting of ice shelves will continue after growth of the forcing stops, because the ocean response time is long and the temperature at depth is far from equilibrium for current forcing. Ice sheets also have inertia and are far from equilibrium: and as ice sheets disintegrate their surface moves lower, where it is warmer, subjecting the ice to additional melt. There is also inertia in energy systems: even if it is decided that changes must be made, it may require decades to replace infrastructure.

The nonlinearity of the ice sheet problem makes it impossible to accurately predict the sea level change on a specific date. However, as a physicist, I find it almost inconceivable that BAU climate change would not yield a sea level change of the order of meters on the century timescale. The threat of a large sea level change is a principal element in our argument (Hansen et al 2006a, 2006b, 2007) that the global community must aim to keep additional global warming less than 1 °C above the 2000 temperature, and even 1 °C may be too great. In turn, this implies a CO₂ limit of about 450 ppm, or less. Such scenarios are dramatically different than BAU, requiring almost immediate changes to get on a fundamentally different energy and greenhouse gas emissions path.

…[/font][/font]

[dixiegrrrrl]

6. The one definite fact about climate change issues is

sooner than later the reports contain the words " much sooner than expected/predicted".

And we have had quite a few "holy shit" moments about the inevitable change.

My holy shit moment was when I heard the words " A person has already been born who will die of catastrophic failure of the planet"

here:

[moniss]

14. Indeed

I also remember seeing this and just sinking in to my chair. I'm afraid that what Hansen and company are trying to tell us is we are f...cked. Since we cannot get our government to even agree on how to pay for our roads it is virtually unthinkable that they will coordinate with the rest of the world on a plan for this. Truly it may be that the last best time for action was back when all of us dirty hippies were trying to get things to change in the 60's and 70's. The mass migration inward along with population growth will prove unsustainable on our available agricultural land. The dwindling fresh water resources etc. will cause countries to war. They can't even share resources peacefully now let alone under major upheaval.

[dixiegrrrrl]

16. Well put...sadly tis true.

Welcome to DU

[Boxturtle]

8. Here is an interactive map for sea level rise:

http://flood.firetree.net/

[GliderGuider]

9. Also consider storm surges

This sea level rise will be occurring in a context of more drastic weather extremes - meaning much higher, more frequent storm surges. Add maybe another 5 meters (?) to the sea level rise to get the "safe zone" on a coast.

And how's that El Nino doing?

[Helen Borg]

10. Just build sea dams!

[blackspade]

12. We have been in a 'holy shit' moment for decades.

But due to inaction from our 'leaders' we now have to endure the consequences.

[Ghost Dog]

18. You have no 'leaders'

when those in such positions are only looking out for themselves (and they are blind).

Imaginative alternatives will arise.

[itsrobert]

15. I think more warming will put more water into the air

making conditions of more rainy seasons. I would not be surprised to see some deserts turning tropical/or jungle like with the added water content in the air.

[OKIsItJustMe]

17. Well, yes and no…

Warmer air can hold more water, so, when it does rain, rainfalls may be more extreme. However, when the air is evaporating water, it can evaporate more.

So, South West US is expected to be drier, while rainfall in the North East is expected to be heavier.