The point of no return

Thwaites

Thwaites Glacier. Image credit: United States National Aeronautics and Space Administration

What were populations potentially at risk, are now the doomed.

CHRIS WOOD: NATURAL SECURITY
Published May 17, 2014

If there were before some footing left for doubt, narrow and slippery though it might have been, there is none left now. The world as it has been for the entirety of human history is on its way to the exits.

What makes this certain is a pair of studies of the behaviour of a glacier most of us have never given much thought to. The West Antarctic Ice Sheet is a vast ice-scape at the bottom of the world, nearly half again larger than Canada. And it is breaking up.

Indeed, the scientific teams that gathered the evidence of the ice-sheet’s retreat say its collapse is now “irreversible.” Evidently this Antarctic ice sheet—unlike it’s larger eastern counterpart—has been frozen at the bottom to what otherwise would be seabed, below the level of the oceans. What’s happening now is that the gale-force winds in the fabled ‘Roaring Forties’ south latitude, freshened further by climate change, are driving relatively warm liquid seawater between the ice and the bedrock it has been frozen to for millions of years.

This is loosening the ice sheet to the point that while it will take a while, perhaps a few centuries, to collapse entirely and drift away, the clock has been set in motion. “It has passed the point of no return,” as the leader of one of the research teams put it.

The fact that this process won’t be completed by next week shouldn’t lessen the impact of this news. Yes, we all habitually discount future costs compared to the present — especially those likely to occur only after we’re safely dead. But think about this for just a moment.

By the time the ice shelf disintegrates completely, our Earth will be unrecognizable. The map that has described the world’s land masses since the pyramids were a gleam in the Pharaoh’s eye, will be obsolete. Even if nothing else happens to contribute to ocean rise, defrosting ten percent of the world’s ice will redraw coastlines from the greatly expanded Gulf of Mexico (bye-bye Mississippi Delta), to the broad and shallow banks that used to be Bangladesh. The sheet holds enough water to lift sea levels by three meters. At that point, major coastal cities like Shanghai, Mumbai, and New York/Newark, and even lesser ones like Vancouver and Melbourne, will have to choose between living behind walls, relocation in whole or part, and becoming future versions of Venice.

It appears the only question left is how soon these choices will become unavoidable. It will clearly take that much ice some time to melt (Antarctica’s not getting that much warmer). But it may not require much of its ice to liquify, on top of other influences on ocean rise such as thermal expansion of warming seawater, to push us over the current informed guesstimate of about a meter’s worth of average sea level rise in this century 

And that is the good scenario. There is a much more alarming, and increasingly likely one.

First, let’s dwell a moment longer on Antarctica’s soon to be former ice. For its frozen host continent and the world’s climate system, this is a very large change occurring very quickly indeed. It is also a one-way change — ”irreversible.” As the scientists report, there are no mechanisms in physics or climatology to reconstitute a continent of ice once it’s been liquified.

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West Antarctica glaciers studied. Red indicates areas where flow speeds have increased over the past 40 years. The darker the color, the greater the increase. The increases in flow speeds extend hundreds of miles inland. Image credit: NASA: Eric Rignot

We have made a world that soon will no longer contain a West Antarctic Ice Sheet, and we will have no choice but to live in that world.

This is precisely the stuff of climatologists’ nightmares: big pieces of the Rube Goldberg machine that is the planetary climate system lurch of a sudden from one stable state (nicely frozen ice sheet) to another one (open water with seasonal ice cover). The new condition alters everything else to which its connected, rearranging familiar weather patterns of rain and snow and drought all around the globe. And there is no ‘restore’ option.

There are a number of links in the climate system that could ‘tip’ this way. Indian Ocean monsoons, the Atlantic Gulf Stream, and frozen methyl hydrates — ‘ice that burns’ — locked beneath the continental shelves, are three that we know something about. There may be others we haven’t detected.

But ‘tipping’ is an apt term. Even without human assistance, some past shifts of the climate machine’s gears have been accomplished in far less time than the West Antarctic Ice Sheet is projected to take to break up completely. Pollon records show that Canada’s southern Vancouver Island once went abruptly from something like its present humid, temperate conditions to the much drier and more wintry climate found today on high mountain plateaus; it took less than 20 years, and lasted for centuries. If the well-preserved frozen corpses of woolly mammoths discovered in retreating Russian glaciers are any indication, the climate can flip even faster than that.

There is no particular reason to think that Antarctica’s western ice sheet will be the last link in the climate chain to ‘tip’ in the decades just ahead, or the most consequential. To put that only slightly differently: not only is the world for which we have built and adapted our societies, our economies and our cities now irrevocably on its way to becoming someplace else quite different. Further unexpected abrupt system changes may throw it even further out of our familiar ken with very little warning.

“Sustainability” is now a lost cause. Very little will be “sustained” as it was on a planet undergoing such change. We should now be talking instead about survival.

If the threat is not immediate, its scale and certainty would impel a more rational society to begin to prepare. It is now inevitable that the homes of hundreds of millions, if not billions, of people, rich and poor, will disappear or become unaffordable or uninhabitable in this century. What were estimates of populations potentially at risk, are now in many cases descriptions of the certainly doomed. The cascading problems this will cause the non-inundated are only beginning to be grasped.

This imminent reality lends an hallucinatory air to our political and business discourses. For the most part, they carry on as though the historical world will last forever and its biggest problems are superpower jockeying and hedge fund speculators.

That world is breaking up and slipping into the sea.

Copyright © 2014 Chris Wood

Contact: cwood@factsandopinions.com

Further reading:
NASA media release: NASA-UCI Study Indicates Loss of West Antarctic Glaciers Appears Unstoppable
Scientific American: ‘Melt of Key Antarctic Glaciers “Unstoppable
Scientific America: “Methane hydrates – bigger than shale gas, “game over” for the environment?”

 

Hear Chris Wood “talk dirty about water,” when he joins a panel of other authors and thinkers on stage at two events convened in Vancouver and Toronto by The Walrus magazine. Join the ‘Walrus Talks Water’ open discussion on May 22 in Vancouver or May 28 in Toronto. Tickets are available …  

Vancouver link: http://thewalrus.ca/the-walrus-talks-water-vancouver/

Toronto link: http://thewalrus.ca/the-walrus-talks-water-toronto/

 

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