Jason Box: Global Ice Loss Far Faster Than Projections: "I'd Say We're In For More Surprises"

[hatrack]

EDIT

Somehow all marine-terminating glaciers across the southern half of Greenland doubled in speed simultaneously between 2000 and 2005. [Readers, this news is what caused me to begin this blog -- I had the one and only epiphany in my life when I read about this.] We didn't yet know why.

In the meantime, scientists tried defining a plausible upper limit for the contribution to sea level rise from Greenland's ice. That was at a time when surging glacier speeds -- ice flow -- was thought to be the dominant conveyer of ice loss, and would be for the foreseeable future. Well, surprise! It became clear that for six years in a row, starting in 2007, ice loss from surface meltwater runoff took over the lead position in the competition for biggest loser. [This was something I thought privately at the time -- that this must occur eventually, but I did not imagine that it would occur so soon. I never bought into the idea that the topography was a limit on glacial outflow and thus would restrain Greenland's contribution to sea level rise.] From 2007 to 2012, nearly each summer set higher and higher melt records, owing to persistent and unforeseen weather that by 2012 would become a signature of climate change.

The competition between how much ice is lost through glacier flows into fjords versus meltwater runoff is intimately synergistic with meltwater interacting with ice flow all along the way. Increasing melt sends more water down through the ice sheet, softening the ice so it flows faster. Once at the bed the water lubricates flow. Squirting out the front of glaciers into the sea, the meltwater drives a heat exchange that undercuts glaciers, promoting calving, loss of flow resistance and faster flow. Put it this way: in Washington, DC, to know what's happening, you follow the money; in Greenland you follow the meltwater.

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Will there be some saving self-regulation of human-induced climate warming and its melting land ice consequences? The enormous increase of heat in our oceans, from past decades of enhanced greenhouse effect, negates any hope that negative feedbacks or even solar output will prevent a much warmer world. The few negative feedbacks we have found for ice -- like more snow as a result of a warming climate, more reflective frost, more efficient sub-glacial water transmission -- are clearly being outdone. And at the global scale, despite some negative feedbacks like more clouds, clearly we are not seeing net cooling. Feedbacks, whether positive or negative, only do their thing after the initial effect. Negative feedbacks don't reverse the perturbation. Seemingly the biggest issue with abrupt sea level rise comes from the now-unstoppable loss of key sectors of West Antarctic ice and the discovery of more marine instability than we thought elsewhere. Like glaciers thinning rapidly in East Antarctica. Or in Greenland, where improved bedrock maps reveal a marine connection an average of 40 kilometers further inland than previously thought. Or like how new fjord underwater mapping reveals greater fjord depths, increasing the odds that deep warm ocean water can communicate with more Greenland glaciers than previously thought. Surprise, surprise, surprise.

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http://climatechangepsychology.blogspot.com/2015/09/jason-box-earths-ice-is-melting-much.html

[gregcrawford]

1. Hmmm... how long can you tread water?

[Bill USA]

2. I'm thinking for all practical purposes any opportunity to slow GW to a stasis has been lost.

Even if we were to begin aggressive investment in Green technologies it couldn't occur fast enough. Best we can hope for now is amelioration - to the degree that that is actually possible. I'm doubtful we will keep GW from getting to the point that it will keep increasing in speed on it's own. At some point even if we took our GHG output to zero it won't even matter. It will be going on it's own. Extractive industries and their pawns the GOP have managed to pretty much stop any serious progress in this regard.

...how did that Woody Guthrie song go: "So long, it's been good to know ya"

[hunter]

3. How do we engineer an organized retreat from the coasts?

It would be best to move or tear down and recycle structures, restore these places to a "natural" state as wetlands, dunes, or barrier islands, and re-establish entire human communities on higher ground ahead of the next super high tide and storm surge.

Or we can just wait until the ocean grinds human infrastructure into a toxic mess, and people who are not wealthy are dispersed as climate change refugees.

There's a right way to face this, and a wrong way.

[hatrack]

4. What will we do? My money's on the latter - the wrong way

Waiting means additional profitable quarters, and growing population means greater numbers of suckers wanting to enjoy the "amenities" of a coastal lifestyle.

[XemaSab]

5. .

.