Climate Skeptics: Matt Ridley, Lukewarmers, and Consensus of “Danger”

Many people frame debates over climate science with a false dichotomy. Either you’re a “denier” or an “alarmist”, with us or against us. But there are many people out there that fall into a different category we can call the “lukewarmers“. The lukewarmers are on board with what we have learned from data and theory. They recognize the robust findings that the Earth is warming, and that most of the change can be attributed to CO2 emissions. However, they don’t believe that the consequences of global warming qualify as “dangerous”. In spite of my own feelings on the issue, I find this growing opinion to be a positive development.

I recently came across the blog of a science journalist by the name of Matt Ridley. He writes some really interesting stuff, but I was particularly intrigued by an article about what the climate wars have done to science. I was turned onto this article from a blog that also seems to fall into the lukwarmer category (

Matt Ridley – Science Journalist

Personally, I have many reasons to be concerned about the effects of climate change, ocean acidification being at the top of my list. But I don’t get to decide how we deal with the effects of global warming so I feel pretty good about the rise of the lukewarmers, because it shows that people generally respect and trust the work of climate scientists, which seems to be half of the battle when communicating our work to the public.

In spite of this positivity feeling, I found Ridley’s understanding of climate science to be lacking some very important details. Additionally, I lose some respect for his message when the latter half of his article turns into a rambling list of examples to argue that the field of climate science has changed to reward alarmism and calls to action.

I can tell you first-hand that this is not the case in climate science. Highlighting how humans will feel the effects of global warming might get you more media interviews and people talking about you on the internet, but it doesn’t translate directly into more funding, or easier access to funding for that matter. You still have to write grants that address outstanding questions with novel approaches to get funded.

Ridley displays his ignorance about the state of climate science when he claims that there is no evidence for a positive water vapor feedback, and no evidence for a tropical tropospheric hot-spot.

“…as the air warms there will be an increase in absolute humidity providing “a positive feedback”. That assumption… could be tested. And the tests come back negative again and again. The large positive feedback that can turn a mild warming into a dangerous one just is not there. There is no tropical troposphere hot-spot. “

The water vapor feedback has absolutely been confirmed, and we have also found evidence of the tropical troposphere warming signal that we expect. Another misconception is that he thinks the paleoclimate temperature proxy records should exactly follow CO2:

“Ice cores unambiguously show that temperature can fall while carbon dioxide stays high. “

He doesn’t provide details on why he thinks this is important, but he’s likely forgetting that the reason ice ages come and go is due to fluctuations in Earth’s orbit, which can obviously change the temperature without having a direct impact on CO2. In other words, its no surprise that the past temperature didn’t follow CO2 exactly, no one expects it to when the carbon cycle is functioning as it should.

At one point in his article he argues that scientists can be in agreement about the past and present, but they cannot predict the future:

“Scientists are terrible at making forecasts… and the climate is a chaotic system with multiple influences of which human emissions are just one…”

First of all, climate is not a chaotic system! It’s deterministic, which makes it possible to make climate forecasts. I guess one could argue that the economy is a chaotic system, and so when you are applying a chaotic forcing to a deterministic system, then the climate is arguably somewhat chaotic. But this is why the IPCC uses emissions scenarios. They are not trying to accurately predict the future, but rather provide a range of possible outcomes based on the uncertainty of human actions. This aspect of climate projection seems to confuse those who can’t sort out the difference between “error” and “uncertainty”.

Ridley goes on to point out that this range of possibilities makes it hard to form a consensus on whether global warming will be “dangerous”.

“The IPCC … thinks the world will be between about 1.5 and 4 degrees warmer…, from marginally beneficial to terrifyingly harmful, so it is hardly a consensus of danger…”

He spends a lot of effort downplaying the consequences of scenarios with little warming, as well as saying how unlikely he thinks the warmest scenarios are. He then, ironically, makes his own predictions about the future of energy use and economic growth that he obviously can’t back up. So in the end he exhibits the characteristics of the people he criticizes.

The biggest issue I have with Ridley’s views are that he plays into the myth that scientists are not willing to debate the validity of their findings.

“The big difference is that these scientists who insist that we take their word for it, and who get cross if we don’t, are also asking us to make huge, expensive and risky changes to the world economy and to people’s livelihoods…. Yet they are not prepared to debate the science behind their concern. That seems wrong to me.”

I think there are several reasons why this myth has persisted. One reason is that debating the methods of a study with a non-scientist is very difficult when they don’t understand the higher level math and subtle physics behind the hypothesis. Another reason scientists might be reluctant to debate a climate skeptic is that those conversations are rarely focused on one topic. I’ve encountered this on several occasions where every comment steered the discussion into a new line of inquiry. At the end of such a discussion both parties usually walk away  frustrated and exhausted.

Ideally scientists should always be objective, but realistically they cannot be expected to be objective all the time. At times they have to switch hats and play the role of a concerned citizen, and in the case of global warming it means being a proponent of reducing CO2 emissions. But in either case, the final value judgement about what is “dangerous” and what to do about it lies in the hands of the larger society. So a vocal lukerwarmer movement is a much better way forward despite any concern scientists may have, especially if the alternative is a more denialism.




3 thoughts on “Climate Skeptics: Matt Ridley, Lukewarmers, and Consensus of “Danger”

  1. George Hagstrom

    Excellent article. I was searching for a discussion of lukewarmers and found your article to address the issue quite welll

    One small quibble: chaos is a phenomenon arising in deterministic systems, characterized by bounded trajectories that are locally unstable. The atmosphere, fluid turbulence, and weather are all chaotic. But climate may not be chaotic, though I am unsure how convincing the evidence is for this, and am not qualified to do anything more than speculate. If annual or decadal time scale events like ENSO are governed by low dimensional chaos, couldn’t there also be longer time scale phenomenon that are chaotic but also relevant on the climate time scale?

    1. Walter Post author

      George, the climate system is most definitely deterministic and not chaotic. There is plenty of evidence to prove this. A simple example is to think of ice age cycles, which are controlled purely by energy balance (solar cycles + orbital cycles + atmospheric composition) and there is not a large sensitivity to initial conditions. I would bet that low frequency modes like ENSO and the PDO also have very little sensitivity to initial conditions, but I’m not sure where the literature is on this question. However, even if ENSO or the PDO could be considered partially chaotic, I am certain that the longer timescale climate variations are still controlled by energy balance considerations and therefore would still be considered deterministic. It is very unlikely that there is a yet unidentified non-linear mechanism that would make the opposite conclusion true. Good question though!


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