Is Climate ‘Lukewarmism’ Legitimate?

By David Middleton – Re-Blogged From

A very thoughtful column by Ross Pomeroy at Real Clear Science…

Is Climate ‘Lukewarmism’ Legitimate?

By Ross Pomeroy – September 25, 2017

To many, prominent writers Matt Ridley, Ross Douthat, and Oren Cass are a baffling bunch. They are the visible proponents of the position that climate change is real, manmade, and occurring as predicted by the Intergovernmental Panel on Climate Change (IPCC), yet it does not yet constitute a worrying or catastrophic problem. They are “lukewarmers.”

So what do we make of these climate change moderates, who do not hold the invalid, unevidenced opinions of those who deny the scientific consensus, yet at the same time, do not ascribe to the apocalyptic scenarios espoused by climate alarmists and the accompanying solutions to avert them?

As far as I can tell, lukewarmers’ views are legitimate. The mountains of evidence present in the most recent IPCC assessment report, comprising more than 9,200 peer-reviewed studies, cannot simply be cast aside as the product of a conspiracy or a statistical fluke of climate models. If lukewarmers accept the science, they are on solid ground.

To his credit, lukewarm New York Times columnist Ross Douthat agrees. “Every lukewarmer, including especially those in positions of political authority, should be pressed to identify trends that would push them toward greater alarmism and a sharper focus on the issue.”

In other words, they must recognize some level of evidence that will cause them to change their views. If they don’t, they have proven themselves not to be lukewarm moderates but dogmatic deniers.

Full Article on Real Clear Science

“Every lukewarmer, including especially those in positions of political authority, should be pressed to identify trends that would push them toward greater alarmism and a sharper focus on the issue.”

This is not a one-sided question. It should also be asked, “What trends would push a lukewarmer towards lesser alarmism and a sharper focus on the issue.”

For this lukewarmer, there is a level of evidence that would cause me to change my views.  This would be some level of evidence above…

Almost every catastrophic prediction is based on climate models using the RCP 8.5 scenario (RCP = relative concentration pathway) and a far-too high climate sensitivity. RCP 8.5 is not even suitable for bad science fiction. Actual emissions are tracking closer to RCP 6.0. When a realistic transient climate response is applied to RCP 6.0 emissions, the warming tracks RCP 4.5… A scenario which stays below the “2° C limit,” possibly even below 1.5° C.


Ensemble of RCP 4.5 models and observed temperatures ( Zeke Hausfather at Carbon Brief).

Note that the 2σ (95%) range in 2100 is 2° C (± 1° C)… And the model is running a little hot relative to the observations.  The 2016 El Niño should spike toward the top of the 2σ range, not toward the model mean.  I am working on a more detailed post on this and “Gavin’s Twitter Trick,” that I hope to post later this week – So I won’t be responding to comments about the hotness of the models in this thread.

Ross Douthat had an excellent column on this in the New York Times (of all places)…

Neither Hot Nor Cold on Climate

Ross Douthat JUNE 3, 2017

LIKE a lot of conservatives who write about public policy, my views on climate change place me in the ranks of what the British writer Matt Ridley once dubbed the “lukewarmers.”

Lukewarmers accept that the earth is warming and that our civilization’s ample CO2 emissions are a major cause. They doubt, however, that climate change represents a crisis unique among the varied challenges we face, or that the global regulatory schemes advanced to deal with it will work as advertised. And they raise an eyebrow at the contrast between the apocalyptic, absolutist rhetoric with which these schemes are regularly defended and their actual details, which seem mostly designed to enable the globe’s statesmen to greenwash the pursuit of economic and political self-interest.

More specifically, lukewarmers look at the Intergovernmental Panel on Climate Change’s official projections and see a strong likelihood that rising temperatures will drag on G.D.P. without leading to catastrophe. They look at the record of climatological predictions and see a pattern in which observed warming hugs the lower, non-disastrous end of the spectrum of projections. And they look at the substance of the Paris accord, which papered over a failed attempt to set binding emission rules with a set of fine-sounding promises, and see little to justify all the anguish and despair over Donald Trump’s decision to abandon it.


NY Times

Although, I do take issue with is this statement:

Lukewarmers accept that the earth is warming and that our civilization’s ample CO2 emissions are a major cause.

The Earth’s average surface temperature has warmed since the 1600’s and our CO2 emissions have played a role in that warming.  Relative to the total carbon flux, our emissions are hardly “ample” and 20-30% doesn’t strike me as a “major cause.”

And I would also take issue with Mr. Douthat’s answer to his own challenge:

I’ll answer that challenge myself: My own alarm over climate change has gone up modestly since the Obama-era cap-and-trade debates, as the decade or more in which observed warming was slow or even flat — the much-contested warming “pause” — has given way to a clearer rise in global temperatures.

If you chart this spike against the range of climate change projections, it brings the trend up into the middle of climatologists’ scenarios for the first time in some years. Maybe that will be temporary and it will fall back. But the closer the real trend gets to the worst-case projections, the more my lukewarmism will look Pollyannish and require substantial reassessment.

The 2016 El Niño spike didn’t bring “the *trend* up into the middle of climatologists’ scenarios.”  The bottom of the 2σ range is the P97.5 case, 97.5% of the model runs resulted in more warming than P97.5.  The model mean is the P50 case, 50% of the model runs resulted in more warming than P50.  The top of the 2σ range is the P02.5 case, 2.5% of the model runs resulted in more warming than P02.5. A major El Niño spike should spike from P50 toward P02.5, not from P97.5 toward P50.  For a discussion of this nomenclature see The Good, the Bad and the Null Hypothesis.

Lukewarmerism is well-grounded in science and economics.  I suppose it could even be viewed as a climatological version of Pascal’s wager.  Matt Ridley also has an excellent article on Lukewarmerism…


Published on: Tuesday, 20 January, 2015
The polarisation of the climate debate has gone too far

This article appeared in the Times on January 19, 2015:

I am a climate lukewarmer. That means I think recent global warming is real, mostly man-made and will continue but I no longer think it is likely to be dangerous and I think its slow and erratic progress so far is what we should expect in the future. That last year was the warmest yet, in some data sets, but only by a smidgen more than 2005, is precisely in line with such lukewarm thinking.

This view annoys some sceptics who think all climate change is natural or imaginary, but it is even more infuriating to most publicly funded scientists and politicians, who insist climate change is a big risk. My middle-of-the-road position is considered not just wrong, but disgraceful, shameful, verging on scandalous. I am subjected to torrents of online abuse for holding it, very little of it from sceptics.

I was even kept off the shortlist for a part-time, unpaid public-sector appointment in a field unrelated to climate because of having this view, or so the headhunter thought. In the climate debate, paying obeisance to climate scaremongering is about as mandatory for a public appointment, or public funding, as being a Protestant was in 18th-century England.



Marlo Lewis has provided a handy list of the range of opinions that come under the “lukewarmer” label. I subscribe to each of these in some form or to some degree:

“In general, I would describe a ‘lukewarmer’ as someone who:

– Thinks anthropogenic climate change is real but  very far from being a planetary emergency

– Takes due notice of the increasing divergence between climate model predictions and observations and the  growing body of scientific literature challenging IPCC climate sensitivity estimates.

– Regards the usual pastiche of remedies — carbon taxes, cap-and-trade, renewable energy quota, CO2 performance standards – as either an  expensive exercise in futility or a  ‘cure’ worse than the alleged disease (depending how aggressively those policies are implemented).

– Is impressed by — and thankful for — the immense albeit usually unsung benefits of the CO2 fertilization effect on  global agriculture and  green things generally.

– Recognizes that poverty remains the world’s leading cause of  preventable illness and premature death.

– Understands that plentiful, affordable, scalable energy (most of which comes from  CO2-emitting fossil fuels) is essential to poverty eradication and progress towards a  healthier, safer, more prosperous world.”

Update 2:

The main point of my article was to draw attention to how ad-hominem, vicious and personal the attacks on lukewarmers now are from the guardians of the flame of climate alarm. Though I had a huge and overwhelmingly positive response, I could not have wished for a better example of my point than some of the negative reactions to this article. An egregious example was the death threats I received from a Guardian contributor and Greenpeace “translator”, Gary Evans.

On 21 January The Guardian published an article by Dana Nuccitelli, specifically criticizing me. The article was illustrated with a picture of the severed head of a zombie. Beneath the article appeared the following comment from “Bluecloud”:

“Should that not be Ridley’s severed head in the photo?”


The Rational Optimist

Other Lukewarmers like Dr. Pat Michaels, Chip Knappenberger, Dr. Judith Curry, Dr. Roy Spencer and Dr. John Christy are routinely subjected to similar ad hominem attacks from the “guardians of the flame of climate alarm.”

So… If you are a fellow Lukewarmer… What evidence would push you toward alarmism?  What evidence would push you toward rejecting human impacts on the climate as being less than a rounding error? (Note: I view the impacts as only being slightly larger than a rounding error).


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