A change is gonna come: no Arctic sea ice and our planet with a different climate

by Gareth on August 24, 2012

The crunch is coming. Before the end of this month, or very soon after, the Arctic sea ice will set a new record summer minimum for area and extent, by any measure. The only question remaining is by how much 2007′s record will be beaten. For the rest of the world, those of us who aren’t habitually glued to the Arctic Sea Ice Blog (where Neven’s counting the dominoes as they fall — one, two, three, four, five, six so far), or who aren’t checking the wonderful images from space that NASA assembles into an Arctic mosaic, or in the Greenpeace team hanging on to a Russian oil drilling rig, we have a simple lesson to learn. The climate of the northern hemisphere has changed, and with it the climate of the planet. And we have precious little idea of how that change is going to affect all of our futures.

Here’s the University of Bremen’s map of the Arctic sea ice today. You might want to commit it to memory, because in years to come this will look like a bumper year…

Bremen20120823

I’ve discussed what this means for the climate of the northern hemisphere before — in fact, I’ve been banging on about it more or less since 2007′s record loss of ice — but Joe Romm at Climate Progress provides a handy summary of why the weather patterns of the northern hemisphere are going to feel the impact of less ice.

Let’s put it simply. When all that blue ocean in the picture above starts to freeze, it is going to give up heat to the atmosphere. A lot of heat. An enormous amount of heat. A decade ago, that didn’t happen to anything like the same extent. That heat has to go somewhere, and it goes into changing the way the atmosphere moves around the northern hemisphere. Look out for interesting winters in Russia, Europe and north America this year and in years to come.

So where do we go from here? I’m on record as projecting that within a decade — perhaps only five years — we will have an Arctic Ocean effectively ice-free in late summer. A few decades later we may see the Arctic ice free in winter. That’s bad news, but the big changes are already with us, and already locked in. They fall within the “climate commitment” — the thirty years or so it takes the atmosphere and oceans to “catch up” with the heat being trapped by any given level of greenhouse gases. Even if we could wave Harry Potter’s wand and magically hold atmospheric CO2 to today’s levels, the warming will continue and the ice will disappear. There is no way back from where we’re going. It’s inevitable, and it’s scary.

To make matters worse, we have next to no idea what this means for the climate of the northern hemisphere, and therefore for the planet as a whole. Take a look at this graph, from the NSIDC’s August 6th sea ice report. It’s a comparison of what climate models project might happen to the Arctic sea ice, and what has actually happened. I’ve been surprised that very few people seem to have picked up on the real import of this graph.

NSIDCmodelobs

The blue line and shading is what the ensemble of models used in the last IPCC report were suggesting might happen. The red line is the multi-model mean for the projections in the next IPCC report, and the pink shading covers the full range of individual model runs. The black line is what’s actually happened so far — not including this year. It’s one run on the real thing. Reality biting. You may safely assume that this years minimum is going to keep that black line bumping along at or below the lowest individual model runs compiled for the next IPCC assessment, which will therefore be out of date before it’s published.

We’ve known since 2007 that the AR4 modelling wasn’t capturing what was happening in the Arctic. It’s now obvious that the latest modelling isn’t capturing it either. A quick eyeball estimate suggests that this year’s minimum shouldn’t be happening for another 10 or 20 years. Some individual model runs might be capturing some of the dynamics of the ice loss, but on average, they’re underestimating it badly. And if they can’t get the sea ice right, then they can’t — because of all that heat being released to the atmosphere every autumn and winter — get the climate of the northern hemisphere right.

We are, not to put too fine a point on it, up shit creek without a paddle, with mud spattered spectacles and no map. This is not good news. It’s all over bar the shouting, of which you may expect plenty. But nothing’s going to change the direction we’re heading. From here on in, it’s damage control only.

[Otis Redding]

{ 12 comments… read them below or add one }

Eli Rabett August 25, 2012 at 12:04 am

let us see, adaptation only, that should make Ethon’s friend Roger very happy. Hope he and his live to enjoy it.

Byron Smith August 25, 2012 at 2:19 am

“it’s damage control only”
I’m not sure this means adaptation only, since mitigation remains the best way to reduce future damage. But maybe I’m missing a joke…

Gareth August 25, 2012 at 8:59 am

Well, perhaps “only” is overstating things a tad. Of course, we should mitigate as much as we can, for the sake of future generations, but we need to be rid of the casual assumption that we have time to play with, and that we might be able to stop it getting too bad. We’re already unavoidably committed to bad, and we can’t stop it getting much worse. We might be able to stop it getting catastrophic if we quit treating the atmosphere as a sewer, but we’re going to have to be lucky.

Byron Smith August 25, 2012 at 9:47 am

Agreed.

David Lewis August 25, 2012 at 5:11 pm

I’m rooting for Hurricane Isaac to take out the Republican Convention.

If enough people contribute, I’ll be able to pour a few pots of boiling water into the Gulf in front of the hurricane to help it build up its power a tad higher.

There was one that came through the Gulf that hit the Loop Current of deep warm water just right and traveled along on top of it, so instead of churning up cooler water from deeper down and limiting its own ultimate power, all that came up as the storm churned was more warm water that kept intensifying the storm. When this thing made landfall it destroyed all the measuring devices that were supposed to tell us how powerful it was. The estimate was 190 mph winds.

That was Camille. We could use something packing a bit more, say 250 mph, that they’d have to invent a new category to describe, say Category 6, that takes out something sizable, like Tampa and the surrounding region, and see what that would do to the mindset of these moron deniers.

As the oceans warm, if hurricanes still form, there isn’t much doubt that they’ll be more powerful. One could come along any time. The oceans are warmer.

The Arctic is just one place where really major changes are underway.

Byron Smith August 25, 2012 at 10:41 pm

As much as the Republican Convention is likely the largest gathering of climate deniers on the planet, I wish all the residents of Tampa (and Haiti!) well and have no desire to see the (relatively) innocent suffer in the hope that it might teach the most obstinately contrarian some kind of lesson they are almost certain to miss.

Gareth August 25, 2012 at 10:59 pm

Thanks Byron. I agree completely.

Macro August 26, 2012 at 4:32 pm

I see they have canceled the first day at least. I wonder if it would ever occur to them why??

Byron Smith August 26, 2012 at 11:28 pm

The first day of the 2008 Rep Conv was also cancelled due to a hurricane (Gustav). So perhaps they put it down to tradition.

Thomas August 27, 2012 at 5:15 pm

Seems that Hurricane Isaac is now aiming smack central for New Orleans once more! This is not good and my heart goes out to those who have perhaps just recovered from the horrors of Katrina.

http://www.nhc.noaa.gov/refresh/graphics_at4+shtml/031346.shtml?tswind120?large#contents

Byron Smith August 28, 2012 at 1:48 am

But due to much cooler Gulf waters than in 2005, likely as “only” a category 1.

bill August 25, 2012 at 5:53 pm

This animation on Neven’s blog really gives the story!

What I want to know is what sort of idiot looks at charts like the ones above and doesn’t think ‘uh-oh!’?

It’s notable that if you go to the intellectual creche Watts runs and that nest of dingbats andy’s so fond of it’s still 2009 and they’re still banging on about the hockey-stick and climategate. And having yet another full-on 5 minute hate of Mike Mann – has there ever been such a grotesque, coordinated and vindictive personal vendetta in the history of science?

Oh, and splitting hairs about recent US temp records and how warm the Antarctic peninsula might have been 11,000 years ago! And generally wittering away with toxic squirrel after toxic squirrel…

To think that an arrogant, ill-informed, strident, hysterical, conspiracy-mongering rabble has helped bring about a situation where we’re watching this unfold but still doing virtually nothing about it is maddening!

But you can see why they wouldn’t want to be contending with reality anymore…

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