Thursday, May 5, 2016

Southern Louisiana faces existential threat from Global Warming.

Reported in The New Orleans Advocate, Sunday, 1 May, 2016.

Sheets of Runoff fall off the Nansen Ice Shelf in the East End of East Antarctica.
According to Sunday's article, coastal researchers Donald Boesch and Virginia Burkett, known for their expertise on reasons why the state’s coast is being flooded by the Gulf, present new findings on why Global Warming is the key to whether Southern Louisiana can be saved or not. Their findings reveal that humanity, individually and collectively, must "[k]eep global temperatures from rising more than 2 degrees Celsius (3.6 degrees Fahrenheit) by 2100, and little will change in Antarctica, which means sea-level rise could be manageable and Louisiana’s coastal plan might succeed." Ditto for Greenland.

According to the following Advocate Graphic, keeping to the 2016 COP21 Paris Accords' goal of keeping below 2 degrees Celsius would limit sea level rise to one foot above today's level at the end of this Century. With Business As Usual, the SLR will reach 6 feet globally. When you factor in Peak Oil / Natural Gas / Coal and the coming decline in fossil fuel outputs into BAU, we'll likely see somewhere in between -- unless Greenland and West Antarctica collapse rapidly, then we'll get 42 feet of SLR in a short period of time. This could actually happen! At the end of the last Ice-Age, ice melt from Antarctica led to 14½ meters of SLR per Century for about a thousand years. Total SLR then was 400 feet.

If we fail the COP21 goal, "and the result could be a sudden, dramatic melting of ice on Antarctica, adding another 3 feet to the current prediction of a 3.5-foot rise in sea level by 2100 — an event that would swamp most of the southern third of Louisiana, even if the master plan is implemented."

Here is what 6 feet of SLR in Southern Louisiana looks like. Just 1 foot looks almost as bad.

The Advocate reports, and it's basically true except for the West Antarctic which is melting like Greenland, that:
Antarctica has been melting at a drip. Indeed, the melting of the ice fields of Greenland — on the northern end of the planet — has been much faster. Located in a warmer environment, those ice fields and glaciers have been pouring water into the Arctic Ocean at rates alarming climatologists. Computer models show sea levels would rise almost 20 feet if all the ice in Greenland melts.

If all the ice in Antarctica melts, those same models show the oceans would rise 200 feet, meaning Baton Rouge would be on the coast.
But there are two monkey wrenches hidden in the Advocate's article, and one is the fact that East Antarctica is beginning to melt like Greenland did less than a decade ago. The other is the effect of gravity on the sloshing sea water in the coming Global Warming induced SLR. What is gravity's effect on sea-level rise in Southern Louisiana?

From the article (boldface emphasis mine):
Any rise would be even higher on the Louisiana coast because this area would have an increasingly strong gravitational pull as Antarctica lost all that ice, Boesch said.

“So if a certain amount of ice melts and raises global sea level by 1 centimeter, in Louisiana, that rise would be 1.2 or 2.5 centimeters,” he said. “Just another reason why we (in Louisiana) have to be really concerned about these sea-level rise figures.”
So at the maximum translation 1 foot of global sea level rise is 2½ feet, 20 feet of G-SLR is 50 feet, 200 feet, 500 feet. That's a lot of water. At just 12 or 13 feet, with our 32-foot barrier walls and seaward embankments, New Orleans will certainly drown. And Baton Rouge and the rest of the state?

The elevation of Baton Rouge is 83 feet above mean sea level. The elevation of Shreveport, 209 feet above MSL. And the highest point in the state, 535 feet.

Ohhhhh, shit.

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