Friday, November 18, 2016

When Does Weather Become Climate

By way of the Verge, Eli was lead to a tweet by Zack Labe, one of the folk who hang out at the Arctic Sea Ice Blog, of a figure made by Wipneus of same

So, on the one paw, as far as weather it's pretty clear that you could not get two places much further away from each other than the Arctic and Antarctic, still what that graph is says is that there is a significant Earthball climate driven albedo decrease and a real positive feedback.

For a long time the line has been why worry, be happy, sea ice in the Antarctic is increasing.  Of course, the two poles are like guy and gal.  Antarctic sea ice surrounds a frozen continent, Arctic sea ice fills an enclosed ocean, but ice reflects sunlight, thus energy.

Antarctic sea ice is a consequence of increased snow down there as the oceans warm and absolute humidity increases.  Eli wrote about that in Curry vs. Curry, a wonderful example of how Antarctic sea ice extent encourages cognitive dissonance and cherry picking, but of course increasing Antarctic sea ice is a prime tree that the denialists swing on.  Of course also, it was also obvious to Manabe in the 1990s that as warming increased the snow would turn to rain, sea ice would start to melt and Antarctic sea ice would decrease.  Even Curry signed on to that.  It has, the Arctic sea ice is growing in more slowly and the Earth is warming.

Weather has become climate to our ill fortune.


Jeffrey Davis said...

Tamino points out that that is 6.9 standard deviations from the mean. Which means what?That's rarer than 1 in 100 billion. But what force has been demonstrated?

EliRabett said...

That far out it is not clear that a normal distribution is appropriate. Wings are tricky things.

Sangeetha said...
This comment has been removed by a blog administrator.

Somebody should tell Sangeetha that warming makes it easier for Ice Station Rabbit to aim Bangalore torpedos at spammers in Chennai


Congratulations on your successful fire solution, Eli.

You have already been mentioned in dispatches

E. Swanson said...

After 37 years of lovely squiggles on the graph, it looks like Mother Nature may have finally thrown the switch to start a new regime. The Arctic has been even more interesting lately:

The North Pole is an insane 36 degrees warmer than normal as winter descends

Kevin O'Neill said...

Re: "The North Pole is an insane 36 degrees warmer than normal as winter descends"

This is refelected in the accumulated Freezing Degree Days. I've taken the DMI N80 data and plotted the difference between recent years and the 1958-2002 climatology.

Per climo we should be to date at 1100 FDDs. We're at 500 (-600 FDDs on the graph). Accumulated FDDs can be used to calculate ice thickness growth. As with many arctic metrics we're in unknown territory.

Bryson said...

WRT the standard deviations, it seems to me that the right way to reason about them here is to say that IF conditions were varying randomly in the ways that have been characteristic of the system up to this point, the current state of the system would be hugely improbable. This invites a probabilistic modus tollens: since the outcome is very unlikely to be due to chance variation, it's reasonable to conclude that it isn't, and conclude that something has changed in the system (figuratively speaking, we're not in Kansas anymore). I think we already knew that, but this is a striking confirmation of that conclusion.

barry said...

When Does Weather Become Climate

A few months is seasonal climate change, not global.

Let's not commit the same error as the pausists.

Anonymous said...

"Lifelong interest in science as a layman, work in the arts, bad at math, underqualified in every way to comment but still let myself converse. On the plus side I'm very rational. On the down side, this actually counts for something on science blogs (it should be de rigeur)."

Ok, thanks for your opinion barry, I apologize for rejecting it absolutely, since you never said anything substantive anyways.

barry said...


Having absorbed your comments here and elsewhere, I can assure you that it is impossible for you to offend me. No apology necessary.

Arctic sea ice developed very slowly in November of 2001, very much comparable in progression to what we've seen so far this month - of course, there was more ice 15 years ago. Nov 2016 will end up being the lowest November in the record. It's not a radical departure from what we've come to expect. It almost attains the epithet 'unusual' - if one was not expecting Arctic sea ice to melt over the long term..

Antarctic sea ice is at an all-time low for this time of year, and has been for most of November. It's because of an early start to the melt season and little interruption in melting. October sea ice extent was lower only in 1986.

Sea ice extent at each pole develops independently. The coincidence of 2 record-breaking low sea ice extents in each pole yields that amazing-looking departure from the rest of the yearly contours. It's way too early to say that Antarctic sea ice has turned some kind of corner. While the curve for 2016 seems improbable, it is within the range of possibility (with melting NH and static SH sea ice), and way too early to call some kind of shift. That nay yet be apparent in hindsight. Not now.

The global surface is getting warmer. Global sea ice is melting. Weather is still weather.

barry said...


Anonymous said...

Barry, you will just have to excuse me for not looking at your rant or perusing your supplied link because I have already demonstrated to my satisfaction and conclusively that you are an outright crank. Sorry.