2018-07-16

Unmasking the negative greenhouse effect over the Antarctic Plateau

It's "new", it's exciting, it's in Nature. Woo. Or at least that one is, by Sergio A. Sejas, Patrick C. Taylor & Ming Cai. But there's also Antarctic Specific Features of the Greenhouse Effect: A Radiative Analysis Using Measurements and Models by Holger Schmith├╝sen (via RR on Twatter). Are they related? I don't know. But this certainly isn't new; S had How increasing CO2 leads to an increased negative greenhouse effect in Antarctica in 2015.

CIP posted about this back in 2016 and we had a "discussion" there.

As you'd hope, the Watties have manged to mangle it: "it also implies that the EAIS is enormously stable with respect to higher CO2 levels". But that's not true. This only gets you an anti-GHE in midwinter, when it's too cold to melt anyway, and it wasn't about to melt in the interior anyway. For stability the edges, and summer, and the ocean are more interesting, as is polewards-advected heat.

Refs


* Town bumps starts tomorrow!

13 comments:

CapitalistImperialistPig said...

Not sure why you quoted the word "discussion." I think we were both civil and addressed relevant points.

However, you did say: ""I never really understood the true reason why +GHG leads to upper cooling in general."

My version of the answer: The stratosphere tends to lack sufficient emissivity in the relevant temperature regimes. That's why it's mostly transparent to IR. On the other hand, it's not transparent to UV, which is why it's warm, though not warm enough to radiate in the UV. More CO2 increases the IR emissivity and allows it to cool more efficiently.

William Connolley said...

I could have left off the quotes; they aren't there for civility, more that we talked past each other somewhat.

Your answer is my answer, which Gavin has nearly convinced me is wrong; in the sense of not being most of the explanation.

CapitalistImperialistPig said...

So what does Gavin say and where?

CapitalistImperialistPig said...

OK, I've now read the discussion between you and Gavin at RealClimate, and I think that you are right and Gavin is nuts. The mean radiating level is not a fixed level in the atmosphere, it's approximately where radiative transport becomes more efficient than convective transport. That level changes when the atmospheric opacity increases. The temperature at that level does not increase, in fact it very slightly cools, since the radiating sphere gets larger. The mumbo jumbo about a "pivot" sure doesn't sound like physics to me.

CapitalistImperialistPig said...

Also, it looks to me like the IPCC summary agrees with us, with a few more details.

MarkR said...

Been a while since I ran the numbers but I always remembered it as being about profitable trade.

More GHG with a hotter side pointing to high emissivity and you warm. More GHG when the hotter side points to a zero emissivity boundary and you cool.

Atmospheric layers trade IR through their top & bottom boundaries. If your top is hotter than your bottom, then more GHG means more trade with space, which doesn't send anything back so you lose. But if your bottom is hotter than your top then more GHG means more trade with the surface, which is happy to do deals and send it all back.

Of course the real answer means solving equations.

Phil Hays said...

How warm will the Arctic get?

https://doi.org/10.1016/j.epsl.2017.03.006

crandles said...

>"It's "new", it's exciting, it's in Nature. Woo. "

better applied to "Global surface warming enhanced by weak Atlantic overturning circulation" ?

crandles said...

I see Realclimate got there
http://www.realclimate.org/index.php/archives/2018/07/does-a-slow-amoc-increase-the-rate-of-global-warming/

Everett F Sargent said...

WMC,

Here's one for you titled .... NYC Bites The Big Grea-z-z-z-z-z-z-z-y Apple? ...
https://www.desmogblog.com/2018/07/20/big-apple-loses-big-oil-judge-dismisses-climate-liability-suit

The money quote?
"The city had argued that the defendants ― Chevron, ConocoPhillips, ExxonMobil, BP and Royal Dutch Shell ― had known about the risks posed by burning fossil fuels since the 1950s and had “engaged in an overt public relations campaign intended to cast doubt on climate science,” an argument Keenan acknowledged in his decision."

The 1950's?

"New York sued in January, claiming the five oil companies are responsible for more than 11% of all the atmospheric carbon and methane pollution since the Industrial Revolution."

WOW!!! 11% SINCE the Industrial Revolution ...

"The Industrial Revolution was the transition to new manufacturing processes in the period from about 1760 to sometime between 1820 and 1840."

Who knew? A 1760 gas pump must be worth a small fortune today.

I think the shities would have a better chance suing India, or China or several countries in the Middle East.

God begat Man. And God proclaimed "Go Sue Thyself."

Everett F Sargent said...

Case 1:18-cv-00182-JFK Document 1 Filed 01/09/18 Page 1 of 67
https://www1.nyc.gov/assets/home/downloads/pdf/press-releases/2018/complaint-filed-8031957-20180109.pdf

The 1950's would appear to be a bit of a stre-e-e-e-e-e-e-e-tch. In NYC, they all lie, just like Baby Trump. API 1951 is not ever referenced. The 1st observational CO2 data paper by SIO appeared post 1960.

Why aren't these people suing coal and natural gas companies and nation state FF companies? Oh wait, it's because the states/cities are all ignorant a$$holes.

William Connolley said...

> you are right and Gavin is nuts

I stuck with that for a while, because I do like the reasoning behind my/your version. However eventually I realised Gavin knows this stuff better than me so I kinda gave in, though without ever quite understanding his version.

> big-apple-loses-big-oil-judge-dismisses-climate-liability-suit

Thanks; blog in progress.

All: apologies for ignoring comments here for a while. I keep forgetting that blogger doesn't mail me any more, and it's been the bumps.

Everett F Sargent said...

so, if you are at the bumps with your moobs will you get a case of the mumps, the boobs or bombs?

I'd go with a case of bombs because you never know when you might want to sink the opposition.