Monday, March 03, 2014

A Different Climate Risk

Current controversies involve a series of claims about climate known with decreasing levels of certainty. The first is that, for about the past century, global temperature has been trending up. So far as I can tell, that is well established. The second is that one cause of that increase is increased CO2 in the atmosphere due to human activity. That seems plausible as a mechanism and fits the rough pattern of what has happened. 

A third claim is that human activity is the main cause of current changes in earth's climate. The support for that is less clear. There have been two periods during the past century when the level of CO2 in the atmosphere has continued to rise for over a decade but surface temperatures have been close to constant. The first was from about 1940 to 1975; we are currently in the second. That suggests that there are causes sufficiently powerful, when they happen to be pushing in the other direction, to balance the effect on global temperature of increasing CO2 . The failure of global climate models to predict the current pause implies that such causes were not adequately taken account of in those models.

Anthropogenic global warming is a scientific theory but it is also a publicity campaign. Central to that campaign is the claim that the science is entirely settled, hence that anyone who rejects any part of the conclusion is either ignorant or corrupt. The rhetorical strategy that supports that claim, one example of which was discussed in a previous post, consists of blurring the distinctions among the claims used to support the conclusion that unless something is done to sharply reduce world output of CO2, very bad things will happen. Anyone who criticizes any link in the chain is labeled a "denier," with the implication that he denies one or both of the most solidly supported claims—that temperatures are trending up or that humans are in part responsible.

In past posts I have criticized what I regard as the weakest part of the argument, the claim that warming on the scale suggested by the IPCC models would produce large net negative effects. This post deals with a risk if the step before that is seriously wrong, if the models turn out to be much less reliable than their proponents claim.

Suppose the current pause in warming continues for another twenty years. I do not believe that the attempts to explain away the current mismatch between theory and data can be successfully maintained for that long a period. If the publicity campaign to convince the public that all scientists agree with the IPCC version of truth is successful and it then becomes clear that that version was false, it will become considerably harder to persuade the public to take seriously scientific opinion in other fields.

15 Comments:

At 8:51 AM, March 04, 2014, Anonymous Max said...

If the publicity campaign to convince the public that all scientists agree with the IPCC version of truth is successful and it then becomes clear that that version was false, it will become considerably harder to persuade the public to take seriously scientific opinion in other fields.

If only! I fear I'm not quite so optimistic. The Cathedral is a hydra - cut off one head, and two more sprout in its place. The "scientific community" (read: the priesthood) has produced more insane/crazy/obviously wrong theories than this, and yet it retains power and influence. This is because power and influence as a scientist are no longer obtained by making accurate predictions. What matters more is the degree to which one's predictions provide a plausible excuse for increasing and expanding the power of those who already hold it.

Science died an ignoble death a long time ago; its body is rotting in a ditch. Very little that's now called "science" deserves to bear the label.

http://unqualified-reservations.blogspot.com/2009/01/gentle-introduction-to-unqualified_22.html

 
At 9:12 AM, March 04, 2014, Anonymous martin said...

The second is that one cause of that increase is increased CO2 in the atmosphere due to human activity. That seems plausible as a mechanism and fits the rough pattern of what has happened.

A third claim is that human activity is the main cause of current changes in earth's climate. The support for that is less clear. There have been two periods during the past century when the level of CO2 in the atmosphere has continued to rise for over a decade but surface temperatures have been close to constant.


If that's a problem for the third claim, it's a problem for the second claim also.

 
At 9:41 AM, March 04, 2014, Anonymous Daublin said...

"If the publicity campaign to convince the public that all scientists agree with the IPCC version of truth is successful and it then becomes clear that that version was false, it will become considerably harder to persuade the public to take seriously scientific opinion in other fields."

I mostly agree, but would push on the concept of what "scientists agree with".

In the public eye these days, it is taken to be results that have passed academic peer review. I believe this type of review deserves to be down-played as a good way to find the truth.

All academic peer review means is that one academic proposed something, and 2-3 other ones approved it. That's a very low bar for someone who has made friends in the academy. It's also not particularly tied to scientific reasoning; it's only scientific to the point that the peer reviewers actually insist on it, and what's to force them to do so?

Instead, scientific support should consist of replicable experiments, successful predictions, and survival against scrutiny. You don't have to be an academic to do scientific experiments or to critique it.

Running a poorly written Matlab program with badly designed statistics doesn't become science just because you're a professor.

 
At 9:53 AM, March 04, 2014, Blogger David Friedman said...

Martin:

The existence of a pause isn't a problem for the second claim, for the reason suggested in the post. If increasing CO2 is one cause of increasing temperatures but there is at least one other thing that causes temperatures to go up or down by similar amounts, then if CO2 is pushing up and the other thing—say changes in the behavior of the sun—is pushing down, the two cancel.

 
At 2:07 PM, March 04, 2014, Anonymous Laird said...

Max beat me to the punch. The general public (notably the American public) has a strong propensity to believe anything written by someone with a string of letters after his name. Probably because our mainstream media is so uncritical (indeed, is probably incapable of critical thought) of supposedly scientific pronouncements.

"Running a poorly written Matlab program with badly designed statistics doesn't become science just because you're a professor." Well said, sir!

 
At 3:14 PM, March 04, 2014, Blogger jimbino said...


The big question in "climate change" is Who the hell cares?

The answer is: the Breeders.

I have long voted by pecker not to breed and I leave it to the breeders to secure the future of their brood. Whenever they agree to buy my faster cars, younger women and older whiskey, I will agree to support the future for their brats.

 
At 4:23 PM, March 04, 2014, Anonymous Peter Donis said...

Adam Frank had a op-ed in the New York Times a few months back bemoaning the fact that the public doesn't trust science as much as it should. That prompted a response from me along similar lines to yours at the end of this post. As long as scientists are willing to misrepresent science when it suits their ideology, science will continue to lose the public's trust.

 
At 12:38 AM, March 05, 2014, Anonymous RKN said...

All academic peer review means is that one academic proposed something, and 2-3 other ones approved it.

On what basis did you reach this conclusion?

In the scientific area where I've published over the past 5-6 years, anonymous peer-review was anything but a rubber stamp. And as a reviewer I've probably rejected more papers than I've passed, several of which were conditional, where I, and in certain cases my co-reviewers, insisted the paper be revised for reconsideration.

 
At 10:11 AM, March 05, 2014, Blogger Ken Burnside said...

David, the increase in CO2 percentage in the atmosphere is almost entirely made up of "fossil" carbon with different Carbon-14/Carbon-12 ratios, so it's nearly a dead certainty that the increase is man-made.

Where I find problems with the AGW hypothesis is two-fold.

1) The models are closed, finicky and neither verifiable nor falsifiable. In 1999, Reid Bryson and I looked at the models used for the Third Assessment Report.

Incomplete data sets.
Malformed data sets that wouldn't load properly into the models.
Incompatible (and contradictory) data sets.
Models that, when we finally did get a data set to load, and run, would give different results from identical runs.
Models that, when we attempted to change one constant (Solar Input Constant) just to see if we could get an error in a predictable direction, did not do so.

I no more trust the models here than I trust the models that say Credit Default Swaps were sound investments with no moral hazard.

2) Data integrity. I touched on this up above. There is no unified data set. Every single one of the research institutes treats their secret recipe of meteorological data as the rheingeld. Sometimes they claim the data is bought from sources that demand it be proprietary.

All three of the major sources (HabCRUt, UAB, and NASA/GISS) use different data sets; these data sets aren't compatible, or independently verifiable.

Merely asking to see the data gets you painted as a denier.

You can prove anything you like if you can doctor your data enough.

I'm not even certain, based on climatestation.org, that the data is even being collected or tabulated properly.

 
At 10:15 AM, March 05, 2014, Blogger AMac said...

At the climate blog The Blackboard, posts and comment threads cover the contributions of different factors to the historical warming trend, the concordance of climate models with the temperature record (recent pause included), and the question of whether climate science is politicized* and how this might affect public opinion.

To fully follow many discussions, a fair degree of scientific literacy and familiarity with background material are helpful.

(I have commented there about the case of Mann et al (PNAS, 2008), an important Hockey Stick paper. Certain of its key conclusions are clearly wrong, but this goes unrecognized by the paleoclimate community. For instance, John Cook uses one of its Hockey Stick graphs to teach about AGW at his "Skeptical Science" website.)

- - - -

* it is.

 
At 11:02 AM, March 05, 2014, Blogger David Friedman said...

RKN:

I don't see any inconsistency between your description of peer review and Daublin's. I have sometimes rejected a paper or suggested changes. But it's still true that "All academic peer review means is that one academic proposed something, and 2-3 other ones approved it."

Those 2-3 being the reviewers. Sometimes they don't approve it.

It doesn't follow that it's a rubber stamp. But neither is it anything close to a guarantee of quality.

And while reviewers are not selected by the author of the paper, there are a variety of ways in which he can influence who reviews it, starting by the decision of what journal to submit to. As a friend with a background in astrophysics recently pointed out, you can eliminate anyone you don't want as a reviewer by including him in your acknowledgements. And, judging by my experience, you can increase the chance someone will be asked to review your paper by including something of his in your references.

 
At 1:19 PM, March 05, 2014, Anonymous RKN said...

@David,

As written, yes, you're right, what I said is not inconsistent with the specific sentence of his (?) I quoted.

However, read in context with the rest of his post (e.g. "a low bar for people who have made friends in the academy"), it sounded to me as though he believes that publishing scientific papers only requires you've made the right friends in academia (thus my "rubber stamp" comment). In my experience there is no basis for reaching this conclusion, thus my question back to him.

As a friend with a background in astrophysics recently pointed out, you can eliminate anyone you don't want as a reviewer by including him in your acknowledgements.

Acknowledgements or references? They're separate and different in the papers I've written & reviewed.

In any case, I can't speak for astrophysics, it's not my area, but I knew of no such strategy to select or deselect who'd review my papers or those of my colleagues. Some journals ask you to suggest reviewers when you submit a paper for publication, but anonymous peer-review means you can never know for sure.

And, judging by my experience, you can increase the chance someone will be asked to review your paper by including something of his in your references.

Maybe. I and my co-authors sometimes speculated on who wrote this or that review of our work, but mostly we were just guessing.

The poster said that instead of peer-review "scientific support" should be found in repeatable experiments, successful predictions, and survival against scrutiny. Except that's precisely what competent peer-review involves, without being perfect of course.

 
At 2:07 PM, March 05, 2014, Anonymous martin said...

David,

I see now I read a bit too fast. I thought the difference between claim 2 and claim 3 was CO2 (in general) vs. (CO2 as a result of) human activity, but the difference is one cause vs the main cause.

 
At 8:30 PM, March 07, 2014, Anonymous Mark Bahner said...

Hi David,

You write, "In past posts I have criticized what I regard as the weakest part of the argument, the claim that warming on the scale suggested by the IPCC models would produce large net negative effects. This post deals with a risk if the step before that is seriously wrong, if the models turn out to be much less reliable than their proponents claim."

One thing you may be missing is that the IPCC's models rely on inputs. Right now, this is in the form of Representative Concentration Pathways. This website has a decent explanation of them:

RCP Guide

There are four basic scenarios. The CO2 concentrations and average temperature anomaly in 2081-2100 (relative to 1850-1900) are:

RCP2.6, 421 ppm, 1.6 deg. C.
RCP4.5, 538 ppm, 2.4 deg. C.
RCP6.0, 670 ppm, 2.8 deg. C.
RCP8.5, 936 ppm, 4.3 deg. C.

Since the warming since 1850-1900 is already a little over 0.8 deg. C., the only scenario with warming over 2 deg. C. is RCP8.5.

However, RCP8.5 has completely unrealistic emissions, especially with regard to emissions from coal, which in RCP8.5 is projected to be almost 10x greater in the year 2100 than in the year 2000. Nobody who knows anything about the subject thinks that's realistic:

Presentation by Dave Rutledge at Caltech on coal consumption in RCP 8.5

The conclusions on page 28 state:

"Coal dominates future fossil-fuel CO2 emissions in RCP 8.5—65%"

"The long-term coal production in RCP 8.5 is 6.6Tt"

"9x the projection for ultimate coal production"

"5x reserves plus cumulative production"

"This is completely contrary to the historical experience—RCP 8.5 should not be used for any purpose"

So the only IPCC scenario with really significant warming is based on completely unrealistic CO2 emissions from coal.

 
At 8:16 AM, March 08, 2014, Anonymous Mark Bahner said...

Hi,

I see that I made a comment that could easily be misunderstood in my last comments. I wrote:

"However, RCP8.5 has completely unrealistic emissions, especially with regard to emissions from coal, which in RCP8.5 is projected to be almost 10x greater in the year 2100 than in the year 2000."

It's the coal *consumption* (tonnes per year) in 2100 that is projected to be 10 times as great in 2100 than in 2000. The CO2 emissions from coal are projected to be much less than 10x as great, because carbon capture and sequestration (CCS) is expected to be widespread in 2100, under the RCP 8.5 scenario.

 

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