Swallow on a line

swallowIt’s been a really amazing day today, and I’ve been out doing some general sight-seeing with some visitors. One of the visitors was getting rather tired of us pointing out what a nice day it was, but it’s hard not to when you live in Scotland (also, it became something of a joke to do it as often as possible :-) ). I managed to get a really nice shot (well, I was pleased) of a swallow on a telephone line, and so I thought I would take this opportunity to post it here. Maybe I’ll even start a “Photograph of the month” theme, but I may not actually have enough good photographs to do so.

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Watt about Roger’s questions?

I haven’t done a Watt about post for quite some time, so thought I would repeat it just this once. Roger Pielke Sr has guest post on Watts Up With That claiming to present seven very inconvenient questions that Gavin Schmidt is too afraid to answer (yes, I’m going to link to WUWT, deal with it :-) ). I’ll ignore the whole rather bizarre “you’re the head of a publicly funded organisation, therefore you need to respond to these questions” framing, and simply address one of Roger’s questions.

Roger refers to a Climate Etc. post, where he discusses an alternative metric to assess global warming. Basically, he just does a simple energy balance calculation which he casts as

Global annual average radiative imbalance [GAARI] = Global annual average radiative forcing [GAARF] + Global annual average radiative feedbacks [GAARFB] (2)

He uses Levitus et al. (2012) to infer a GAARI, since 1955, of 0.39Wm-2 ± 0.031 Wm-2, which is for the oceans only, so it’s increased by 10% to give 0.43Wm-2 ± 0.031 Wm-2. The radiative forcing (GAARF), since 1750, is 2.29Wm-2 (1.13 to 3.33 Wm-2). Since 1950, this becomes 1.72Wm-2. The radiative feedbacks he essentially takes from Soden et al. (2008) and considers the Planck response, water vapour, clouds, and albedo. Together, they sum to -1.21Wm-2K-1. The change in temperature since 1955 is about 0.6K, which gives a net feedback response of -1.21Wm-2K-1 x 0.6K = -0.73Wm-2.

Therefore we have a GAARF of 1.72Wm-2 and a GAARFB of -0.73Wm-2. If we sum these we get 1.72 – 0.73 = 0.99Wm-2, which Roger points out is about twice as large as the value estimated from Levitus et al. (2012). This was one of the things that Roger highlights and asks for Gavin’s best estimates for these terms.

So, why is there an apparent discrepancy between the system heat uptake rate estimated using an energy balance approach, and that estimated from ocean heat content measurements? Well, Roger appears to have made a number of mistakes in his calculation. Firstly, he did not correct for the fact that the oceans are only 70% of the surface. Secondly, it shouldn’t be the global average radiative imbalance, it should be the change in radiative imbalance over the time interval considered (i.e., the difference between what it is at the end of the time interval, and at the beginning). In the most recent decade, Levitus et al. (2012) suggest a radiative imbalance of 0.7Wm-2 (full surface plus increased by 10%). During the earliest decade (1950s) it was probably about 0.2Wm-2. So, the change is around 0.5Wm-2. Roger also forgot to include lapse rate feedback, which – according to Soden et al. (2008) – is probably around -0.75Wm-2K-1. So the feedback is actually -1.96Wm-2K-1, giving a net feedback response of -1.96 x 0.6 = -1.176Wm-2. Combining that with the change in external forcing gives 1.72 – 1.176 = 0.544Wm-2, pretty much the same as that estimated from Levitus et al. (2012). Of course, I’ve just eyeballed some of the numbers, and there are uncertainties to consider, but it certainly seems as though one can come close to reconciling the model-based estimates, and the observations.

So, I think that clears up one of Roger’s questions. The reason for the discrepancy is – I would suggest – simply because Roger’s calculation isn’t correct, not because there really is some kind of major discrepancy between model estimates and observations. Apologies, of course, to Gavin for butting in :-)

Edit and acknowledgement: I’ve just realised – and Chris Colose has confirmed – that the temperature feedback includes the lapse rate, so Roger’s feeback estimate is about right. However, I still maintain the the correct radiative imbalance is the difference between what it is at the end of the time interval and at the beginning, not the average over the time interval. Hence, the discrepancy is not quite as great as Roger’s calculation suggests.

Posted in Climate change, Gavin Schmidt, Science, Watts Up With That | Tagged , , , , | 207 Comments

Lukewarmers – a follow up

I was reading (don’t ask me why) Ben Pile’s analysis of this whole Lukewarmer issue. If anyone wants an illustration of why I said things like

Apparently being a Lukewarmer also means that if you can’t actually find an explicit description of someone else’s view, you can just make one up…… Apparently, virtually everyone else is a Green activist….. Lukewarmers also seem to think that “play the ball, not the man” applies only to other people

in my previous post, Ben’s post is a good place to start. I wasn’t going to analyse his post, or discuss what he says – as that would be silly – I was simply going to comment on what Ben says in his update. Roger Pielke Jr appears to have objected to being a labelled a Lukewarmer, and so Ben updates his post with

Roger Pielke Jr. tweets that he rejects the term ‘lukewarmer’, and adds: “Distinguishing political perspectives according to ECS is antithetical to robust policy & inclusive politics”.

I don’t always see eye-to-eye with Roger Pielke Jr, but this is – I think – a very good point, assuming I’ve interpreted it correctly. Fundamentally, the evidence base should be broadly the same. What we decide to do, given that evidence base, is what we should really be discussing. That people seem to be arguing about, or defining themselves according to, something like ECS, rather than about what we should do given the range for ECS, is what lead to me to say

Lukewarmerism appears to be a way of attempting to justify a certain policy position, rather than a genuine attempt to develop a position based on a reasonable interpretation of the available evidence.

To be fair, I would dislike it if someone claimed that my scientific position was motivated by my policy preferences, so the above is – as should be obvious – a general impression, and is not aimed at any specific individual. I also realise that Lukewarmers are more diverse than my simple description might indicate. However, it does seem as though many Lukewarmers do define themselves according to what they think climate sensitivity (ECS) will be, and – typically – choose a likely/probable range that is not consistent with that presented by the IPCC/mainstream science.

Let me clarify a few things, though. Continuing to investigate climate sensitivity and trying to constrain the range more accurately is – of course – a good thing; that’s what science is about. Discussing the strengths and weaknesses of the different lines of evidence is also a perfectly valid thing to do; again this is a fundamental part of science. There is a caveat, though; that’s why you talk to experts, they can tell you about the different lines of evidence and why some might be stronger than others. Also, you don’t simply dismiss – or accept – some evidence just because you can find an expert who supports that view; you typically try to get the views of a sufficiently large group of experts, like – oh, I don’t know – maybe the IPCC?

I’ll finish with a final comment. Richard Betts wrote a guest post here called label the behaviour, not the person. I agree with that general sentiment; discussing a particular viewpoint, or behaviour, is vastly different to labelling some specific individual. However, as Brigitte Nerlich points out, Lukewarmer appears to be a self-label, rather than a label generated by others. This makes it slightly tricky. It’s one thing to label others in a manner that they might find objectionable, but another to use one that they themselves have developed. The current objection seems to be that some – like me – are defining it incorrectly, but I’m still having trouble seeing how, as everything I read seems broadly consistent with my understanding of the general position.

Anyway, I’ll simply reiterate the point I was trying to make here, and which I think Roger Pielke Jr was getting at; we don’t get to choose our own evidence, and defining yourself according to some subset of the evidence is a poor way to ensure robust policy making. One might even argue that the attempt to develop a self-label is inherently political and divisive.

Posted in Climate change, Climate sensitivity, ClimateBall, IPCC, Science | Tagged , , , , , | 90 Comments

Lukewarmers part II

I wrote about Lukewarmers a while back. Idiotracker has also discussed them, and Eli calls them Luckwarmers. Tamsin Edwards’s recent Guardian article has, however, reinvigorated the topic and Brigitte Nerlich has tried to understand the emergence and spread of such labels.

My understanding of the basic Lukewarmer viewpoint is that they regard lower climate sensitivity values as being more likely than the IPCC suggests, and higher one as being less likely. Replace IPCC with mainstream scientists, or whatever other term seems more appropriate, if you wish. Since the impacts probably depend on the temperature change, this means that Lukewarmers presumably think that, for a given future emission pathway, the impacts will probably be less severe than the IPCC suggests. This then means that we potentially have more time to develop sensible policy and technology, and that we can focus on other important things, before focusing on what should be done with regards to climate change. It would seem, though, that Lukewarmers essentially ignore – or downweight – evidence that suggests that their preferred probability distribution function may be incorrect.

I have, unfortunately, made the mistake of reading some recent posts by self-professed Lukewarmers. I won’t link to them, but you can probably find them if you want to. It appears that there are some subtleties about Lukewarmers that I may not have appreciated. The range for the scientific view seems quite broad, and appears – in some cases – to essentially include the full IPCC position and – in others – to be verging on outright denial. There are some other subtleties. Lukewarmers apparently regard themselves as being in the sensible middle, between two extremes. This presumably means that everyone else regards themselves as being in one of the ridiculous extremes? Lukewarmers apparently want to do reasonable, good things, as opposed to everyone else who wants to do silly, bad things. Apparently being a Lukewarmer also means that if you can’t actually find an explicit description of someone else’s view, you can just make one up, because it is obvious what it has to be. In addition, if you can find one, you can still say “they might have said this, but it’s clear that they really meant that”. Apparently, virtually everyone else is a Green activist. Lukewarmers also seem to think that “play the ball, not the man” applies only to other people; labels are discouraged, unless you are a self-professed Lukewarmer.

So, all in all, I’ve been rather confused by this whole episode. I think it probably stems from my assuming that the Lukewarmer viewpoint was a scientific viewpoint, rather than a political viewpoint. I suspect that Chris Shaw’s comment on Brigitte Nerlich’s post puts things into the right perspective. Lukewarmerism appears to be a way of attempting to justify a certain policy position, rather than a genuine attempt to develop a position based on a reasonable interpretation of the available evidence. If things go as they have in the recent past, I will be vitriolically told that I’m completely wrong about this, by people who then say things that are entirely consistent with what I’ve just said.

Moderation note: I know my tagline has changed, but civility is still encouraged. Let’s keep comments civil and thoughtful. I’ve also discovered that Lukewarmers tend to be very sensitive. Mild criticism is, according to some Lukewarmers, an attack. As such, I’m going to moderate heavily if necessary; I’m not interested in any attacks on individuals – well, mild criticisms.

Posted in Climate change, Climate sensitivity, ClimateBall, Global warming, IPCC | Tagged , , , | 182 Comments

Tropospheric hot spot?

I think I might just briefly mention the recent Sherwood & Nishant paper, Atmospheric changes through 2012 as shown by iteratively homogenized radiosonde temperature and wind data, which appears to show what some have called a tropospheric hot spot. It’s also been covered elsewhere. As the abstract of the paper says (my bolds)

Temperature trends in the updated data show three noteworthy features. First, tropical warming is equally strong over both the 1959–2012 and 1979–2012 periods, increasing smoothly and almost moist-adiabatically from the surface (where it is roughly 0.14 K/decade) to 300 hPa (where it is about 0.25 K/decade over both periods), a pattern very close to that in climate model predictions. This contradicts suggestions that atmospheric warming has slowed in recent decades or that it has not kept up with that at the surface. Second, as shown in previous studies, tropospheric warming does not reach quite as high in the tropics and subtropics as predicted in typical models. Third, cooling has slackened in the stratosphere such that linear trends since 1979 are about half as strong as reported earlier for shorter periods.

As I understand this, it is indicating the the rate of warming in the troposphere exceeds that at the surface. This is essentially because water vapour does not condense (and release latent heat) equally at all altitudes. It tends to do so more in the at altitudes where the pressure is around 200mb (a few km above the surface) than it does at the surface. This leads to faster warming at these altitudes in the troposphere than at the surface, and produces a negative lapse rate feedback.

Credit : Figure 1 from Sherwood & Nishant (2015)

Credit : Figure 1 from Sherwood & Nishant (2015)


In general, it seems that this result is broadly consistent with climate models, but that there are some differences, such as it not reaching quite as high in the tropics and sub-tropics as predicted. I don’t quite understand the significance of this. I also don’t quite understand the significance of stratospheric trends being about half as strong as reported earlier. Maybe others who do could clarify in the comments. Overall, however, this seems to be an important results which appears to confirm our basic understanding. I’m looking forward to Turbulent Eddie accepting that we now have evidence for a tropospheric hot spot :D

Posted in Climate change, Climate sensitivity, Science | Tagged , , | 77 Comments

Thinking globally

Isaac Held has a recent post called addicted to global mean temperature, that I wanted to highlight. It’s quite relevant to the energy balance models that I’ve dicussed before. You should probably just read Isaac Held’s post, but I thought I would highlight a few things that I found quite illuminating.

One point that the post makes relates to Cowtan & Way (2014) and discusses the implications of undersampling of the temperatures in some regions of the globe. If you try to infill in the undersampled region, you might find that this increases the global temperatures and, consequently, increases estimates of the transient climate response. However, this doesn’t mean that the response to CO2 has increased everywhere, it’s really telling us that

the response to CO2 has a different pattern than what we had thought, not that the response to CO2 is everywhere larger than previously estimated.

I will add, however, that it would seem that improving the sampling would then make it easier to do comparisons with models that do not suffer from this kind of undersampling.

What I found particularly useful was the explanation for why we might expect the feedback response to be non-linear, or – more correctly – not globally constant as we warm.

In models, the effective strength of the radiative restoring is stronger for perturbations in tropical temperatures than for perturbations in high latitude temperatures. In addition, temperature responses are less polar amplified in the initial as compared to the final stages of the approach to a new equilibrium with elevated CO2.

However, as pointed out above, this really means that if we consider the initial period only, we would mostly be underestimating the response in the polar regions.

I’ll just add one more thing that I found interesting and that relates to what I’ve been stressing recently; climate change is essentially irreversible on human timescales. Even if we were to entirely halt emissions, the decay in atmospheric CO2 would largely balance the rise in temperatures, resulting in global temperatures remaining fixed. However, even this is subtler than I had realised

As another example, consider the accumulated emission perspective on long-term climate change after emissions cease, in which slow carbon uptake over centuries compensates approximately for the slow equilibration of the climate to the evolving CO2 levels. The southern ocean plays a leading role for both carbon and heat uptake. And from a global perspective these are competing to change the same global mean temperature. But CO2 is well mixed in the atmosphere on time scales longer than a year or two, so any uptake of carbon affects both hemispheres with roughly equal radiative forcing. But uptake of heat in the Southern Oceans affects the southern more strongly than the northern hemisphere. This distinction can get lost when discussing this accumulated emission perspective.

If I understand this properly (and I may not) what I think it is pointing out is that the northern hemispheres – with more land – equilibrates more rapidly than the Southern Hemisphere. Therefore, what will probably happen is that the NH will rapidly warm towards a higher temperature than the SH, which will maintain an energy imbalance, with most of the energy going into the oceans. The global temperature may be largely fixed, but that doesn’t mean there will be no regional variability, or that there won’t be regional warming/cooling (as the NH and SH equilibrate). At least, I think that is right.

Anyway, those are a few things that I found interesting. You should probably read Isaac Held’s post, as there is more than just this and I may not have quite captured all the subtleties. I think it is quite easy to simply think in terms of globally averaged quantities, while forgetting that there are significant regional variations (both in time and space) and that these can influence what we might infer if we consider globally average quantities only.

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Guest post: Climate variability research: did the sceptics make us do it?

This is a guest post by Prof. Richard Betts, Head of Climate Impacts at the Met Office, about Lewandowsky et al’s forthcoming paper, which suggests that climate skeptics influence climate scientists. The post speaks for itself, so I won’t say anymore. Remember, though, that even though I’ve changed my tagline, civility is still encouraged. Richard’s post starts now.

Stephan Lewandowsky and co-authors have published an Executive Summary oftheir forthcoming paper* Seepage: Climate change denial and its effect on the scientific community. The authors suggest that climate scientists are allowing themselves to be influenced by “contrarian memes” and give too much attention to uncertainty in climate science. They express concern that this would invite inaction in addressing anthropogenic climate change. It’s an intriguing paper, not least because of what it reveals about the authors’ framing of the climate change discourse (they use a clear “us vs. them” framing), their assumptions about the aims and scope of climate science, and their awareness of past research. However, the authors seem unable to offer any real evidence to support their speculation, and I think their conclusions are incorrect.

As their example of scientists apparently giving undue weight to “contrarian memes”, Lewandowsky et al focus on what they describe as the “asymmetry of the scientific response to the so-called Œpause'”. They assert that “on previous occasions when decadal warming was particularly rapid, the scientific community did not give short-term climate variability the attention it has recently received”. They do not specifically identify the “previous occasions when decadal warming was particularly rapid”, but it’s fair to assume that they are referring to the 1990s, probably the period 1992-1998. This was the most recent occasion when global mean temperatures rose rapidly for a few years, and previous such occasions occurred before climate science had become established as a widely-established field of research.

This assertion, however, is incorrect. Short-term climate variability did receive a lot of attention in the 1990s ­ see extensive discussion in the first 3 IPCC Assessment Reports, and brief discussion by Hawkins et al (Nature Climate Change, 2014). One specific example of a high-profile paper on this topic is Sutton & Allen (Nature, 1997), but there are others.

It is perplexing that Lewandowsky et al do not seem to be aware of this research on short-term climate variability. One explanation may be that there is more effective communication of research. Social media opens up many more channels through which climate scientists can communicate their work, instead of this communication being done by middle-men in the mainstream media or vested-interest organisations such as NGOs as in the 1990s. Those outside of the climate science community are therefore much more likely to be exposed to topics that are of interest to the scientists themselves, rather than just topics which interest newspaper editors or environmental campaigners.

Possibly Lewandowsky et al are wondering why there was not a raft of papers specifically focussing on the observed temperature record between 1992 and 1998. The reason is simple ­ this was not a particularly surprising event. When global temperatures rose rapidly few a few years after 1992, this was very easily explained by the tailing-off of the short-term cooling influence of the Mount Pinatubo eruption. This had cooled the Earth briefly by injecting large quantities of ash into the stratosphere. Indeed this cooling had been successfully predicted by Jim Hansen using a climate model shortly after the eruption. A few years later, 1998 was an exceptionally warm year globally because of a major El Nino event. The fact that these two events were well understood and even partly predicted in advance meant that there was less of a puzzle to be solved, so less motivation for extensive research on the drivers of global temperature over these specific years. In contrast, the trajectory of global temperatures in the last 15 years or so was not specifically predicted in advance. Although global temperatures remain within the envelope of uncertainty implied by multi-model studies, this is not the same as actually predicting it. So this time, there is a interesting puzzle to be investigated.

I have not actually counted or systematically reviewed the papers on variability in the 1990s compared to those in more recent years, so although there was a lot of variability research in the 1990s, it is still possible that there are more variability papers in the latter period. However, even if this is the case, there are other reasons for this. Users of climate information (and hence funding bodies) are increasingly interested in adaptation planning, which tends to require information in the nearer-term when natural variability dominates. More recently this has matured into the agenda of Climate Services, which includes forecasting on seasonal, inter annual and decadal timescales. This has led to the development of new scientific capabilities to address this need, eg. very large ensembles of climate models, initialised forecasting (where models use data assimilation to start from actual present-day data rather than pre-industrial), increased resolution, and greater computing power. So in addition to the scientific motivation to study variability which already existed in the 1990s, there is additional motivation coming from stakeholders and funding bodies, and also more extensive capability for this research.

Lewandowsky at al regard research into natural variability as “entertaining the possibility that a short period of a reduced rate of warming presents a challenge to the fundamentals of greenhouse warming.” Is there any evidence at all of climate scientists actually thinking this? I don’t think so. This indicates a fundamental misconception about the scope and aims of current climate science – the authors seem to assume that climate science is entirely focussed on anthropogenic climate change, and that natural variability is only researched as a supplementary issue in order to support the conclusions regarding anthropogenic influence. However, the truth is very different ­ natural variability was always of interest to scientists as part of understanding how the climate system works, and Climate Services and the ambitions for short­ term forecasting are now major research drivers. It is true that some papers have also used the observational record to try to understand and constrain key quantities of relevant to anthropogenic change, namely equilibrium climate sensitivity and transient climate response, but this is hardly addressing the “fundamentals of greenhouse warming”, ­it is simply trying to reduce uncertainty in one of the key aspects of it. Such studies certainly do not limit themselves purely to the “pause” period ­ instead, they include it in a much longer longer period of many decades, since this is the timescale of relevance to changes in greenhouse forcing. Exclusion of recent years from such studies would lead to misleading results, so of course the “pause” period is going to be included.

So the perceived “asymmetry” can be easily explained purely as an evolution of scientific focus and capability over the last 25 years. Nevertheless, the hypothesis of psychological influences is intriguing. Could it still be happening even though the specific example of increased research on variability can be explained by other factors? Lewandowsky et al suggest three mechanisms by which their proposed “seepage” may occur ­does the evidence support these proposed mechanisms? Here I focus on the situation in the UK, as this is where I am most familiar, and also because this is where a focus on the “pause” is quite common.

The first proposed mechanism is dubbed “Stereotype Threat”. The idea is that climate scientists are worried about being stereotyped as “alarmists”, and react by downplaying the threat. I agree that there may be some evidence for this in the IPCC and the global climate science community – for example, although the Fourth Assessment Report (AR4) included projections based on the high-end A1FI scenario, these were performed with the simpler Integrated Assessment Models rather than full, complex General Circulation Models. Moreover, the media focus on the projections sometimes did overlook the A1FI projection of warming up to 6.4C by 2100. (Indeed I was was told by a long-established and respected environment journalist that the media were very much steered away from the A1FI result when AR4 was published in 2007.) This was indeed one of the motivations for my paper “When could global warming reach 4C?” as felt that the A1FI scenario had not received the attention it warranted. However, despite this possible example of reticence by the IPCC, the UK community does not seem to have followed suit. The A1FI scenario was used in the UKCIP02 and UKCP09 climate projections, and a number of high ­profile UK conferences focussed on the higher-end risks of climate change, eg. “Avoiding Dangerous Climate Change” in Exeter in 2005; and “4 Degrees and Beyond”, Oxford, 2009. UK research institutions are leading two major EU-funded consortia on the impacts of “high-end climate change” (I’m coordinating one of these, HELIX, myself). So while talk of the “pause” is commonplace in the UK climate science community, this does not seem to be accompanied by shying away from discussing projections and risks of higher-end climate change.

The second proposed mechanism is dubbed “Pluralistic Ignorance”, which refers to people thinking that their views are more in the minority than they really are. The authors offer the speculative example of public discourse that IPCC has supposedly exaggerated the threat of climate change. This does not seem to be the case in the UK ­ there is general public acceptance of anthropogenic climate change, and uniquely non-partisan political consensus on taking action on mitigation. For example, a recent article in the Guardian states:

“Britons are more likely to agree the climate is changing than at any time in recent years, with nearly nine in 10 people saying climate change is happening and 84% attributing this somewhat or entirely to human activity, new research has found. Two-thirds say they are concerned by global warming.”

Over the past 25 years, successive UK governments have led the world in supporting climate science and in developing climate policy both at home and internationally. The Conservative Prime Minister Margaret Thatcher personally founded the Met Office Hadley Centre, and at the same time the UK was prominent in establishing the IPCC. For the first 4 IPCC assessment reports, the UK government played a cental role by supporting an IPCC Co-Chair and Technical Support Unit in the Met Office Hadley Centre. The UK has been central to the UN climate negotiations, and under the Labour government of 1997-2010 was the first country to put in place its own legislation on reducing emissions and planning adaptation (the Climate Change Act). In the 2010 election, the Conservative Party manifesto was keen to promote its environmental policies, and prior to the recent election the three main parties signed a statement supporting continuation of the Climate Change Act. Hence, if there is any country in the world where climate scientists can feel that their research is valued by both the public and politicians, it is the UK.

The final proposed mechanisms is dubbed the “Third person effect”, and refers to the idea that someone may think that others are more easily persuaded than they are themselves, and react to this. This seems quite plausible, but I fail to see why this would not apply equally to arguments from activists and politicians aiming to persuade people of the threat of climate change. In fact, given the widespread public and political agreement on anthropogenic climate change in the UK, it seems far more likely that the “Third Person Effect” would apply to being persuaded by arguments in favour of acting on climate change than by those against it.

So overall I do not see that “seepage of contrarian memes” is necessary to explain research on the recent slowdown in global surface warming, nor do I see any evidence that this is likely to be occurring in the UK climate science community where such research is prominent.

There are further intriguing questions arising from the facts that (1) UK scientists discuss the “pause/slowdown”, (2) the UK public acceptance of anthropogenic climate change and (3) successive UK governments have been, and remain, world-leaders in climate policy. If climate scientists have indeed allowed themselves to be influenced by “contrarians”, it would appear that this has not prevented widespread acceptance of anthropogenic climate change or the development and implementation of climate policy. Indeed, if scientific discussion of the “pause/slowdown” is indeed seen by the public and politicians as considering a “contrarian meme”, could it actually be the case that a clear willingness to consider a range of viewpoints could actually enhance the credibility of climate scientists? Therefore could open discussion of the “pause” actually increase the confidence of the public and the government in their advice that climate change is real and man-made? It seems fair to suggest that an intelligent and thoughtful public and politicians would take scientists more seriously if they are seen to be objective ­ indeed some research does support this supposition.

So to conclude, I think Lewandowsky et al are incorrect that scientific research and discussion into the recent climate variability has arisen as a result of the “seepage of contrarian memes”. Variability has always been a key topic in climate research, and if this has become more extensive or visible in this recently, it is simply the result of improved science communication, more specific research questions and evolving capabilities within climate science. The evidence also suggests that even if “seepage” is real, at the very least this seepage has had no influence in watering-down UK public opinion and political action compared to other countries – and that possibly the opposite has occurred because the public are more convinced by seeing scientists being objective.

Footnote:
*it seems they expected the paper to be published at the same time, but it is not yet available. Stephan offers to send the corrected proofs to anyone who emails him – his contact details can be found here.

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