Wednesday, October 09, 2013

Natural Variability Is Local

UPDATE:  C also Fergus

An everygreen in denial land has been that natural variability covers all climate change.  All of those econometrician types,  and some of Eli's favorite crazy aunts are fond of this, but they are lumpers.  There is no single natural variability.

The tropics, of course, are the region with the most species, the most biodiversity, a hell of a lot of people, and an almost unchanging climate.  Why do the bunnies think that the tropics have the most species, the most biodiversity and so many people?  It is a lot easier dealing with a constant climate than one that varies all over the place.  For one thing you don't have to change your fur with the seasons.  The flip side is that nature in the tropics is not so well structured to deal with even small changes.  While variability is low, human climate forcing driving the system beyond its usual local limit is dangerous. 

 Of course, high latitudes are vulnerable exactly because climate variability there is so high.  In that case one worries about damage that is hard to reverse from large excursions (things don't always break the way you want).  If there is a really warm summer, and the permafrost goes really non perm, it's hard to dig the Alaska oil industry out of the muck.

A paper to be published tomorrow in Nature The projected timing of climate departure from recent variability by Camilo Mora and friends at the University of Hawaii that makes an important contribution by recognizing this issue.  Well, it does come from Hawaii, one of the places with the most constant climate on earth.  They examined historic climate using 140 years of data for the past, and Earth System Models for the future (You want data from the future? Sorry, that is not currently available).  They define exceeding natural variability at any position as exceeding the limits of the 140 year data record for various periods of time.  For reference RCP45 is an emissions scenario that brings the CO2 mixing ratio in 2100 to 538 ppmV

Here we present a new index of the year when the projected mean climate of a given location moves to a state continuously outside the bounds of historical variability under alternative greenhouse gas emissions scenarios. Using 1860 to 2005 as the historical period, this index has a global mean of 2069 (+18 years s.d.) for near-surface air temperature under an emissions stabilization scenario and2047 (+14 years s.d.)under a ‘business-as-usual’ scenario. Unprecedented climates will occur earliest in the tropics and among low-income countries, highlighting the vulnerability of global biodiversity and the limited governmental capacity to respond to the impacts of climate change.  Our findings shed light on the urgency of mitigating greenhouse gas emissions if climates potentially harmful to biodiversity and society are to be prevented.
The years when variability will be exceeded forever on an annual basis are shown in a) below, and on a monthly basis in b) below.  Eli directs your attention to the summers in the Indian subcontinent and Southeast Asia.

Mora et al., also looked at evaporation, transpiration, sensible heat flux, precipitation and surface pH of the oceans.
the projected timing of the ocean’s climate departure was pushed forward to this decade when pH was considered alongside sea surface temperature. Global mean ocean pH moved outside its historical variability by 2008 (+3 years s.d.), regardless of the emissions scenario analysed.
Eli wonders if Richard Tol would agree that this paper explicitly endorses the IPCC consensus?


willard said...

Perhaps Richard Tol would have the same answer to your question, dear Eli, than he had to Richard Betts:

> @richardabetts I was distracted by another section (where the authors knowingly misrepresented the literature) @ClimateOfGavin

dbostrom said...

"...authors knowingly misrepresented the literature..."

Right, just like Tol's "Pachauri is a corrupt choo-choo engineer" useless rubbish.

The trouble with no accountability for mistakes is that mistakes keep on being made. Some guileless people are going to read Tol's latest fiction and make the mistake of thinking they should listen to him, that Tol's imagination is reliable.

Andy S said...

Actually, Eli, I would likely have rated the Mora et al abstract as an implicit endorsement only, since it doesn't quite explicitly state that humans are the cause of climate change and there is no quantification of the degree of human contribution to warming.

Yeah, we were conservative. People who have tried to rate the abstracts for themselves probably found that out fairly quickly.

richardtol said...

IPCC WG3 AR4 Chapter 11: Compare the FOD, SOD and published version. Text changes from perhaps positive, to perhaps positive/perhaps negative, to definitely positive.

Then look up the comments. Referees point out that the effect may be positive or negative. Authors agree with referees.

Also note that the IPCC reports that a particular study reports a positive effect whereas it actually reports a negative effect.

dbostrom said...

Tol, you've got a backlog of corrections to make before picky people like me are going to bother reading beyond your name. Credibility is conservative.

As is so often the case, where and when somebody chooses to speak is much more interesting than what they say. Strikingly conspicuous.

a_ray_in_dilbert_space said...

Richard Tol is the name;
Vagueness and ambiguity are the game.

richardtol said...

You suggested I was bluffing so I invited you to call my bluff.

I gave you chapter. You have Google. Apparently, you need verse too. I refer to the impact of induced or endogenous technological change on the costs of greenhouse gas emission reduction.

You can start with the Synthesis Report, where the IPCC draws a conclusion that is at odds with the literature -- and trace it back to the FOD of Ch11 to see how the authors twisted and turned to reach this remarkable finding.

You can also take my word for it.

EliRabett said...

Would you like pancakes with that Richard?

dbostrom said...

Tol: "You suggested I was bluffing so I invited you to call my bluff."

Which bluff? Your Pachauri bluff? I hope so; bluffs are best handled in the order they're delivered.

Which word should I take? Do you mean "Pachauri must go?" Why should he? Is that still an open question?

richardtol said...

I of course referred to "...authors knowingly misrepresented the literature..."

Pachauri is going, which is good. The frontrunner to replace Pachauri is likely to inflict worse damage on the IPCC.

dbostrom said...

"Einstein died, so the Theory of Relativity is wrong."

Serendipitous coincidence isn't a substitute for "sorry, I was hyperventilating over nothing." Pachauri isn't leaving for the reasons that exist between your ears, Dr. Tol.

EliRabett said...

Pachauri is fucking 73 years old, 74 by the time WG3 is published. Rent a clue Dick.

Of course Eli remembers that Bob Watson has never been Tol and Pielke's favorite either.

Jay Alt said...

Dubious squeaks from the dismal science.

dbostrom said...

Very invested in the new whispering campaign, doesn't want to talk about the old one.

richardtol said...

Kindly refresh my memory on my opinion of Bob Watson. Google is of no help.

EliRabett said...

Easily, what you have written is easily the greatest on this laudable topic. Eli will concur with your conclusions and will thirstily look forward to your future updates. Saying thanks will not just be sufficient, for the The Rabett will instantly grab your comments to stay privy of any updates. Solid work and much success in your academic enterprise!

richardtol said...

Seriously. I don't think I've ever written much about Bob Watson. He's one of the smartest, hardest-working, most effective people I know. I disliked his micromanagement, especially after the more laid-back style of Bert Bolin.

The Very Reverend Jebediah Hypotenuse said...

"I don't think..."
"... I know"
"I disliked..."

First-person concerns have hereby been noted.