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« Leavers on the line - Josh 338 | Main | Greenpeace's failed predictions »

Cost of global warming wildly exaggerated

Enthusiasts for a carbon tax tend to lick their lips at the sheer size of the numbers that have been conjured up out of the economic models. They see a door opening to massive economic changes, with societal change on the horizon too.

Today the door has been pushed back somewhat, with a new paper in Energy Economics by a multinational team of authors led by Zuzana Irsova of Charles University in Prague (there is a preprint here). She and her colleagues have been looking into published estimates of the social cost of carbon and find good evidence of a strong publication bias. You can probably guess which direction the bias is in:

The largest corrected mean SCC we get for estimates with uncertainty is USD 134 per ton of carbon at 2010 prices for emission year 2015; because the uncorrected mean of these estimates is 411, our results indicate that the reported estimates of the SCC are exaggerated at least threefold on average because of the selective reporting bias. The largest corrected mean SCC we obtain for study-level estimates with or without uncertainty is 61, which is more than four times less than the overall mean of 290.

These are costs per tonne of carbon. In costs per tonne of carbon dioxide, their results are coming out at $39, so you can see how this is going to dampen the spirits of those, like Ackerman and Stanton, who advocate for a value in excess of $1500.

And with a delightful sting in the tail, they close by suggesting that this may actually mask the true scale of the problem:

[O]ther studies suggest that some of the parameters used for the calibration of integrated assessment models, such as climate sensitivity or the elasticity of intertemporal substitution in consumption, are likely to be exaggerated themselves because of selective reporting...which might further contribute to the exaggeration of the SCC reported in individual studies...


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Reader Comments (71)

It's the name of the game. If they played a straight bat to every supposed problem how would they terrify politicians into action?

'Climate sensitivity to CO2 is marginal and any warming would be net beneficial' doesn't frighten the horses much. It's the most egregiously exaggerated political issue under the sun, bar none.

Aug 21, 2015 at 10:46 AM | Unregistered Commentercheshirered

Publication bias has been shown for many issues, so we should not be surprised to see it in climate research too. It is nice to see it quantified using state-of-the-art statistical methods.

Aug 21, 2015 at 11:03 AM | Unregistered CommenterRichard Tol


booming echo-y voice from behind the clouds - paging Professor Lord Nicholas Stern of Brentford!

Aug 21, 2015 at 11:07 AM | Registered Commentertomo

What does the cost-benefit analysis look like?

Aug 21, 2015 at 11:23 AM | Unregistered CommenterSlywolfe

As has been said elsewhere about "smart meters": (

The team of physicists that [investigated] the massive use of new intelligent power meters [says it was] was:-

“a hasty decision that had been poorly thought through“.

Sounds like it was made the same way as most other decisions about responding to the perceived threat to humanity of anthropogenic forced climate change - wind power, biomass energy, anti- fracking, closure of coal and nuclear fission fired generating capacity, carbon taxes, etc.etc.

Looks like more sheer incompetence from our political class ( not unexpectedly).

Aug 21, 2015 at 11:23 AM | Unregistered CommenterFriend of Botswana

What a complete waste of money and intellectual manpower it all is when it is known that CO2 has an immeasurably small effect on the climate and the economic benefit of increased atmospheric CO2 is massive. There are probably millions of people worldwide wasting time and money on useless climate-related activities, who could (possibly) be employed doing something useful with their lives.

Aug 21, 2015 at 11:37 AM | Registered CommenterPhillip Bratby

At some point political enthusiasm for decarbonising the economy will have to be explained. In the context of long running ideas like AGW, politicians are generally not much more than departmental mouthpieces - the civil servants are pushing the idea. It wouldn't surprise me if civil servants fell for the Peak Oil theory and saw decarbonising as an 'answer' .....if MMGW was the necessary trigger/scare, so be it.....If you can believe in one dud theory why can't you as easily believe in another dud theory? "Civil servants and credulity" - nice title for a thesis.

Aug 21, 2015 at 11:38 AM | Unregistered Commenterbill

Friend of Botswana
I think the whole thing is a good example of "the man who wants something is always in a stronger position than the man who doesn't want him to have it."
What the enviro-activists very actively want is the destruction of "civilisation as we know it" and its replacement with a world-wide peasant society of about half the number of humans there are at the moment (some suggest they will get the latter part of their wish by as early as mid-21st century) living at subsistence levels and ruled benevolently (and if you believe that you'll believe anything) by an élite composed mainly of those self-same activists.
The reason they are "winning" is that no sane human being in any position of power or authority or with the genuine well-being of the people in mind — and I think it's fair to suggest that the majority of politicians across the globe more or less fall into that category — could imagine that anyone could be quite that malevolent, corrupt, stupid, arrogant, uncaring, self-serving and any other adjective you care to come up with.
So nobody takes any action positively to confound any of their knavish tricks until it is (almost, we hope) too late.
And always remember that this has nothing to do with climate change or global warming; that is only the quite specious justification. Any other horse would have done equally well. It's just that this one ran better.

Aug 21, 2015 at 11:46 AM | Registered CommenterMike Jackson

Mike, somewhere in all this is that the forces of decency, civilisation, order etc have STILL not figured out how to deal with negative to cope with the wrecker who is squealing about justice and fairness (when meaning something entirely different.....there has been a huge reluctance to engage intellectually, to treat the wrecking classes as intellectual equals whose arguments can be torn apart just like any other adults...look at what an easy ride eg trade union leaders get on the radio.... .because the wreckers (claim to) speak for the 'oppressed' then they too are part of the oppressed and we must not be beastly to them, given all our advantages....its time to forget that crap and go for their throats

Aug 21, 2015 at 12:14 PM | Unregistered Commenterbill

Another area of bias is in allowance for reality.
Allegedly up to a degree of warming has been human caused so far. Estimates in Stern are based on 4-6 degrees of eventually warming.
Estimated cost functions of cost C against temperature T are at least quadratic. I estimated that behind Stern it was at least a quartic i.e. C=f(T^4).
That is 2 degrees of warming would generate 16 times the cost of 1 degree.
3 degrees of warming would generate 81 times the cost of 1 degree.
4 degrees of warming would generate 256 times the cost of 1 degree. etc.

Given that the predicted short-run signals of impending catastrophism (accelerating sea level rise, increasing droughts and floods, more extreme weather etc. etc.) have been mostly wrong or grossly exaggerated, one would have expected the estimates of the social cost of carbon to have been revised downwards to near zero by now.
Alternatively, one would expect a weighting factor to be added for speculative conjectures.

Aug 21, 2015 at 12:40 PM | Unregistered CommenterKevin Marshall

I'm still not seeing that it's even a cost rather than a benefit.

Aug 21, 2015 at 12:46 PM | Unregistered CommenterJamesG

Paleontology never shows an upper limit to the benefits of warming and always shows the detriments of cooling. A warmer world sustains more total life and more diversity of life.

And the greening? Downright miraculous; the greening alone is feeding a billion people.

Aug 21, 2015 at 12:56 PM | Unregistered Commenterkim

The dismal science continues to be dismal, but somehow continues to grow in influence, prestige and wealth, for the simple reason that there are no headlines, TV interviews, taxpayer funded studies, consultancies, or global meetings without exaggerated alarmism.

Fight The Blob.

Aug 21, 2015 at 1:13 PM | Unregistered CommenterMikky

The same rules in the domain of publication that apply to the evolution of climate models apply to literature that 'assess' the (environmental/financial) impact of warmth. You've skewed the field to favour one kind of outcome; an average of the outcome is therefore only a reflection of the magnitude of the skew.

Aug 21, 2015 at 1:14 PM | Registered Commentershub

I agree with you but most people like to be "nice". (Yes, really). And they prefer to think well of other people just as they want other people to think well of them. Your hard-nosed businessman and his PR department and the activist (political, environmental or whatever) doesn't give a fig what you think of him; he wants his own way.
I've said before that in my days as a journalist (of sorts) my first reaction to a press release was "what are they wanting me to print that I don't want to print?" Mostly PR stuff ended up in the bin. In local papers there used to be more than enough local stuff with photos and local ads to fill the paper anyway but on the rare occasions that I looked for something to fill a gap and looked for a decent PR story I would always contact the organisation concerned and dig, dig, dig.
Occasionally I used to get a better story — and not the one they wanted me to write either!
Unfortunately it seems that modern reporters don't have enough background knowledge (of anything apparently!) or the time/inclination to do a bit of research into what and who they are challenging. So they don't challenge.
Add to that the corporate mindset of whichever news outlet you're talking about and it's hardly surprising that certain sectors will get a free ride.
The cure is good journalists but given the standard of journalism courses these days I shouldn't hold your breath.

Aug 21, 2015 at 1:31 PM | Registered CommenterMike Jackson

Mike, Yes I understand. But the time surely has come for some at least to stop being 'nice'. I particularly like stories which highlight Progressives hypocrisy, in particular where they send their kids to school. Hypocrisy is so toxic, and its in connection with their children that the Progressives true colours are revealed (ie in general they believe very little of what they spout, dissemble though they might). Thats why Leftists so hate that line of attack, and try to shut it down with the faux-indignant 'leave my kids out of this' cry. No, no, no, lets drag your kids right in, let their shining little faces show you up for the hypocrite and shit you really are....My favourite of this genre is the despicable Diane Abbot, '"Mz Equality, Justice, and anti-Colonialism 1978" (and 79) who not only sent her little soldier to St Pauls, but had the crust to claim it was all his own idea....and no-one has ever asked how someone on an MPs wage could remotely afford St Pauls, even the day boys fees....As you say, journalists don't dig these days

Aug 21, 2015 at 1:51 PM | Unregistered Commenterbill


Your position is echoed by that of blogger Ben Shapiro, when he says:

The left’s arguments are chock full of inconsistencies. Internal inconsistencies – inconsistencies that are inherent to the left’s general worldview. That’s because very few people on the left will acknowledge their actual agenda, which is quite extreme.

The way to debate them, Shapiro suggests, is to expose those extreme positions; they talk about 'regulating carbon polluters' which sounds reasonable, when what they mean is 'dismantling capitalism'. Naomi Klein has come closest to publicly articulating that extreme position.

Aug 21, 2015 at 2:39 PM | Unregistered CommenterRick Bradford

Well this is jolly good news and peer reviewed to boot. I'll buy a Guardian newspaper tomorrow for the front page headline.

Aug 21, 2015 at 2:40 PM | Unregistered Commenterssat

The amount of money spent on trying to assess the cost of an unknown, based on guesswork, multiplied by greed, and goaded by avarice, is wholly disprortionate, to whatever the thingummy might have been in first place.

Aug 21, 2015 at 2:52 PM | Unregistered Commentergolf charlie

Richard Tol, Bjorn Lomborg and the Rogers will appear momentarily

Aug 21, 2015 at 3:00 PM | Unregistered CommenterEli Rabett

Eli it's a pleasant surprise when friends pop in unexpectedly. It's sadly predictable when unwanted guests turn up.

Aug 21, 2015 at 3:12 PM | Unregistered CommenterTinyCO2

Rick yes their language is that of defending the down-trodden when what they mean is f*cking up the middle classes

Aug 21, 2015 at 3:23 PM | Unregistered Commenterbill


you said
"Mike, somewhere in all this is that the forces of decency, civilisation, order etc have STILL not figured out how to deal with negative to cope with the wrecker who is squealing about justice and fairness"
The problem is that our politicians are not part of those forces of decency (with a few notable exceptions). In particular It has been many years since this country had a real leader with the integrity and the intelligence required. With David Cameron we have hit rock bottom.
I was once of the opinion that making any decision was better than not making a decision but Cameron proved me wrong.

Aug 21, 2015 at 4:14 PM | Registered CommenterDung

I was always taught that you do a "cost/benefit analysis".

Aug 21, 2015 at 4:30 PM | Unregistered CommenterJohn Peter

This may be way out, and please excuse my ignorance if it is, but is there any chance that this information could have any impact on the cost-effectiveness/economics of CCS? I still can't believe that otherwise sensible people, particularly engineers, think that CCS is a viable solution.

Aug 21, 2015 at 4:30 PM | Unregistered CommenterIan P

From the paper

In contrast, Tol (2011) finds that newer studies tend to report smaller estimates of the SCC. Our results are different because we include new studies published between 2012 and 2014; these studies often report large estimates of the SCC as they try to incorporate potential catastrophic outcomes of climate change.
So as the pause continued the researchers started imagining even worse scenarios. Hmm.

In other words, the science is getting more and more divorced form the observations. It's no surprise that they get the social cost of CO2 wrong then.
They are getting worse at this science thing.

Aug 21, 2015 at 4:33 PM | Registered CommenterM Courtney

I'm not that confident this is going to make a difference.

When the EPA can run an economic benefit analysis out 300 years just to get the answer they want. When the President can claim lowering CO2 will benefit asthma sufferers or that sea level rise is threatening our security while he purchases a house on the beach and not be ridiculed in the MSM. When politicians can repeatedly refer to "carbon pollution" as if it is a real thing and people accept it, then the battle appears lost.

Aug 21, 2015 at 5:00 PM | Unregistered Commentertimg56

Ian P

CCS is in la-la land. No project has ever demonstrated that it works on the scale that would be required.

Aug 21, 2015 at 5:50 PM | Registered CommenterDung

The first and foremost way to change tack as a nation is to re-classify the supposed experts that publish politically entrenched scientific advice designed to force governments into a course of action beneficial for minority groups and against the direction that the majority have democratically voted for.

The Marxist terrorists Greenpeace are starting to be recognised for who they really are by nations and WWF are increasingly being condemned by other environmental groups for sucking up to multi national corporations for their ten pieces of silver instead of defending indigenous cultures.

Aug 21, 2015 at 6:10 PM | Unregistered CommenterLord Beaverbrook

"With David Cameron we have hit rock bottom."

I think that's unfair on Blair and Brown. They led us full steam ahead into the 2008 crash (spiralling house prices are a good thing!). Doubled down on tory policies they previous laughed at and brought in a new era of style over substance politics and cynical manipulation. A good day to bury bad news. No wonder Blair regretted the freedom of information act. It was a weapon against tory sleaze that showed what miserable hypocrites they were.

Aug 21, 2015 at 6:44 PM | Unregistered CommenterDaveJR


I never look at some research and wonder whether it will make a difference or not, I ask myself "is it true/right?" or "is it wrong?"

Aug 21, 2015 at 6:45 PM | Registered CommenterDung

Dave JR

I agree with the things you said about Blair and Brown but I think Cameron decided to out do Blair. Blair was at least consistent, when he told a lie he stuck with it.
Cameron has no idea what his beliefs are until someone tells him.

Aug 21, 2015 at 6:50 PM | Registered CommenterDung

The fact that this is all predicated on the revenues raised being used to mitigate climate change....... as if.

Aug 21, 2015 at 7:47 PM | Unregistered CommenterDave_G

If they are going to put Massive Taxes on Fossil Fuels to discourage people from using them knowing full well Fossil Fuels are a necessity will they reduce Taxation and VAT on everything else.

Aug 21, 2015 at 8:02 PM | Unregistered Commenterjamspid

and then again any future government can use the revenue from Carbon Taxes to fund another illegal invasion in the Middle East to secure Western Oil Supplies.Then set up a Public Inquiry and sit on the report that comes out about it for a few more years.Hoping it will be eventually forgotten about.

Aug 21, 2015 at 8:09 PM | Unregistered Commenterjamspid

Mikky writes:
The dismal science continues to be dismal, but somehow continues to grow in influence...

In view of Banksy's 'dismaland' in Western-super-Mare, any chance he could do something about the current state of 'climate science'?

Aug 21, 2015 at 8:44 PM | Unregistered CommenterPhilip Foster

@ Aug 21, 2015 at 12:14 PM | Bill

Exactly. The smart axiom for discourse and intellectual engagement (SADIE), "Do unto others as they would do unto you."

Aug 21, 2015 at 10:05 PM | Unregistered CommenterManfred

Eli 3.00pm, another climate science prediction gone wrong.

Aug 21, 2015 at 10:32 PM | Unregistered Commentergolf charlie

It is estimated that 337 billion tonnes of carbon (dioxide) has been released into the atmosphere since 1750 (
Even at the modest estimated cost of $39 per tonne the social cost of industrialisation so far has been over $13,000,000,000,000.

Aug 21, 2015 at 11:18 PM | Unregistered CommenterChris Hanley

@ bill

I certainly understand your frustration, I've been of that mind on occasion too

But the idea of being "rude" to them - children's stuff, I'm afraid

You may have seen a comment in this thread from the Eli of Wabbett. A comment typical of him, playing the ad hom. Now try to be rude to him - he doesn't give a flying f8&k what you think, you will make no headway at all. Tis the power of Noble Cause Corruption, you see

The *only* way to upset these people is to garner MSM publicity adverse to them. That really does upset them, no end, since they are of the (accurate) view that their biggest achievement by several orders of magnitude is to have a majority (bare majority, perhaps) of the populace believing them, so any threat to that is fiercely fearful for them. Most anxious-making, as it were

And the issue with that line of attack is that the MSM in their vanity believe that they have the unfettered power to decide the public agenda, not you or I or I anyone else

Aug 21, 2015 at 11:28 PM | Unregistered Commenterianl8888

The taxes on gasoline in the UK ARE huge.

Aug 21, 2015 at 11:52 PM | Unregistered CommenterEli Rabett

What does the cost-benefit analysis look like?

At 1kg/km of CO2 and average 5km trip in an ambulance, that's 200 lives/tonne at $1,000,000/life = $200M
Looks like a net benefit to me.
You can do similar calculations for heating, refrigeration, lighting - even financial transactions can save lives.
Remember too, that the left also loves the "If it saves one life, it's worth it" line - time to throw that back at them.

Aug 21, 2015 at 11:53 PM | Unregistered CommenterKneel

To be clear Tol, Lomborg and Pielke Jr. have set the social cost of carbon very low compared to what others think optimal. How is this any different?

Aug 21, 2015 at 11:54 PM | Unregistered CommenterEli Rabett

the greening of the Saharah makes of course many people migrate: these people are used to dry climate so they will move to Londonistan which is famous for dry Martinis or so the avg Guardianista will tell you if she can keep her nonsense job a bit longer with that, off our back

Aug 22, 2015 at 1:07 AM | Unregistered CommenterVenusNotWarmerDueToCO2

The EPA uses about $9.1M as the value of one human life.
Increases your estimated benefit by almost a factor of ten.
If anthro CO2 is feeding 1 billion, the EPA says it is worth $9100 trillion.
$9100 trillion divided by 0.337 trillion tons gives about $27000 per ton Social Benefit of Carbon.

Aug 22, 2015 at 4:55 AM | Unregistered CommenterChris y

Surely, the “cost” of global warming has to be negative, when you take into account all the benefits we have received, so far, and continue to receive? The costs being incurred are in attempts to negate these benefits, or to counter falsely-perceived threats. It is akin, you might argue, to charging for the fuel used in burning vast amounts of crops merely so that you can claim a crop shortage, then charge for the concrete to lay over the once-productive ground.

Aug 22, 2015 at 6:29 AM | Registered CommenterRadical Rodent


Laughing at the opposition can be pretty effective too- many of them are not noted for their sense of humour

Aug 22, 2015 at 7:43 AM | Unregistered CommenterMessenger

Not so.

Pielke Jr and Lomborg have never published an estimate of the social cost of carbon, not high, not low, not anything.

My published estimates span the range: I've published some of the lowest estimates and some of the highest, but most of my estimates are somewhere in the middle.

Aug 22, 2015 at 8:30 AM | Unregistered CommenterRichard Tol

This is the grand illusion; it is a benefit, not a cost. Economists will eventually figure out what Gaia already has.

Aug 22, 2015 at 9:33 AM | Unregistered Commenterkim

The title of this thread allows me to dust the cobwebs off my AGW beliefs once more ^.^
There is no cost of any kind involved with the emission of CO2 in any quantities, however large because additional CO2 does not cause additional warming at 400 ppm.
Our host does not approve of this view but it IS relevant to the thread.

Aug 22, 2015 at 11:12 AM | Registered CommenterDung

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