David Whitehouse is very confused

David Whitehouse, who is Science editor for the Global Warming Policy Foundation, has an article in the The Spectator, apparently presenting the truth about the global warming pause. It is, to be polite, very confused. For starters, it defines the pause as being a period over which the trend was no longer statistically significant.

Well, this is silly, because (as this post higlights) the intrinsic variability means that there will always be a period over which the trend will not be statistically significant (defined as the uncertainty in the trend being large enough that you can’t rule out that the trend is 0). If you give yourself the freedom to change the start point of your trend calculation, then you can always claim to be in period where warming has paused. This is essentially what Skeptical Science’s Escalator was developed to illustrate. Even though there are likely to be periods when surface warming is slow does not mean that there is not some long-term surface warming trend. Just to be clear, the long-term trend is just over 0.18oC per decade, and there are no indications that this is slowing.

What’s slightly worse, is that to supposedly illustrate his point, David Whitehouse showed two graphs of global surface temperatures; one from January 1997 to December 2014, and the other from January 2015 to May 2017. However, what he didn’t make clear is that the y-axis scale on the latter graph was not the same as that on the former graph. Hence, his presentation (as Roger Jones pointed out) hid the incline. His two graphs made it appear (as was clearly his intent) that there had been little warming between January 1997 and December 2014, and that there was then a rise, and a comparable drop, between January 2015 and May 2017 (i.e., little warming overall).

However, if you look at the figure on the right (which shows both periods on the same graph) it’s clear that there has been warming, and if you use the Skeptical Science Trend Calculator, it is statistically significant (i.e., it is almost certainly not 0). Furthermore, HadCRUT4 shows less warming than all the other surface temperature datasets (it suffers from coverage bias). Berkeley Earth, GISTEMP, and HadCRUT4 with kriging all show warming of around 0.18K/decade, while NOAA suggests around 0.17K/decade. So, it’s clear that even though surface warming may have been slower than was expected over the last decade or so, there is still a long-term warming trend and there is no real indication that it is slowing overall.

This whole the pause may not be over argument is extremely disingenuous. If we continue to pump CO2 into the atmosphere, it will continue to accumulate. If the surface doesn’t warm, or warms slowly, then we will build an increasing planetary energy imbalance. As the Ocean Heat Content indicates, the system continued to accrue energy even during the period when surface warming was slower than had been expected. The only way the system can return to energy equilibrium is through surface warming. The only way that it can be suggested that we may be returning to a pause/hiatus is by changing the start point of the trend estimation.

When it was clear that 2015/2016 were likely to be record warms years, many mocked organisations like the Global Warming Policy Foundation by suggesting that they will start to promote a narrative that there had been no warming since 2015/2016. Even I thought that this was so ridiculous that not even the Global Warming Policy Foundation would be silly enough to go ahead with such a strategy. Of course, nothing really surprises me anymore, so I should probably not be surprised that they are choosing this strategy, even though it is patently nonsensical. It’s almost as if they don’t even listen to their Academic Advisors. Hold on, maybe I have that the wrong way around?


As Magma points out in this comment, Whitehouse’s article claims that

for the past decade or so, although average global ocean temperatures have slightly increased, the oceans of the northern hemisphere and indeed most of the southern hemisphere have not warmed at all.

Credit: Wang et al. (2017)

The Figure on the right is from Wang et al. (2017) and shows Ocean Heat Content trends for the different oceans, for different time periods, and for different datasets. Although there are some differences between the different datasets (which is partly what the Wang et al. paper was addressing), they all show warming for the period 1998-2012.

Posted in Climate change, Climate sensitivity, ClimateBall, Global warming | Tagged , , , , , , , , | 59 Comments

Meeting people

I was away all of last week on a mini UK-research tour. I had some work to do with people in Leicester, including with somone who has just finished doing a PhD with me and who has a couple of really interesting projects that we’re trying to finish (if they read this, I promise I’ll send that info tomorrow 🙂 ). After a few days in Leicester, I headed down to Exeter as I also had some work to do with someone there (we got an amazing amount done in a couple of days) and I also gave a seminar to their Astronomy group.

I also got a chance to visit the UK Met Office, which is based in Exeter. Mark McCarthy, who is science manager of the National Climate Information Centre, invited me to visit for a bit of a tour. It was very interesting; I’d just finished reading This Thing of Darkness, a novel about Charles Darwin and Robert Fitzroy, the captain of the Beagle. Apart from the author thinking highly of Piers Corbyn, it’s really excellent. The Met Office started as a department under Robert Fitzroy, and he spent a lot of his own money on barometers, that he designed and distributed. They had an example of one of his barometers in the library.

I also got a chance to have a chat with John Kennedy, who maintains the sea surface temperature record, and Tyrone Dunbar, who had spent time seconded to the Department of Energy and Climate Change. I didn’t get a chance to meet Richard Betts, as he was busy rocking Glastonbury 😉 . We mostly chatted about climate communication. I’m not sure that we came to any strong conclusions; I think it’s very difficult and I don’t have any great insights. Do your best; be honest; try to be nice (I don’t always succeed, but I’m trying to do better); it’s probably more difficult than you can imagine; it’s important; maybe we should endeavour to be supportive of those who do so. Anything else?

One issue with blogging and tweeting, is that you’re somewhat isolated; you don’t always get a sense of how it’s being received and it’s sometimes hard to interpret tone from what others say online. It’s therefore nice to actually meet people and have a chance to have a proper conversation. In the context of my blogging, I’ve only done it a few times, but it’s always been pleasant, I’ve always learned something, and it’s always helped to clarify things. Of course, there may be some for whom this would not be the case.

Posted in Climate change, ClimateBall, Science | Tagged , , , , , , , | 17 Comments

The Science Police

Keith Kloor has an article in Issues in Science and Technology called The Science Police. I became aware of it because he linked to one of my posts so as to highlight a comment by Michael Tobis. I tried to leave a comment, but it hasn’t appeared, so thought I’d write this instead.

The general gist of these science police type arguments is that there is some group of people who police what it is acceptable to say and who do their utmost to prevent those, who don’t toe the line, from speaking publicly. It will typically involve examples of supposedly biased reviews (of papers or grant proposals), difficulty getting a place to speak at meetings, and criticism that supposedly crosses some line.

Some of these may well be examples of poor practice, but sometimes (often?) not. Sometimes reviews can be justifiably negative and sometimes you just don’t get selected to speak at meetings. It doesn’t necessarily imply some kind of insidious attempt to silence those who might present alternative views; it could simply be that the person’s work isn’t very interesting/good, rather than because it challenges the orthodoxy (I would argue that the former is much more likely than the latter).

However, a big part of Keith Kloor’s article covered the conflict between Realclimate and Roger Pielke Jr. As an example, he highlights a comment by Roger Pielke Jr on this post in which Roger says:

My objection with RC is not that you guys act politically, but that you act politically but claim not to be. This mismatch is what I have argued is a factor that contributes to the politicization of science.

It seems Keith Kloor might have a point, but not in the way he intended. There do appear to be people who try to police science, but they’re people like Roger Pielke Jr who think that they get to define what is acceptable public behaviour by scientists. The above not only accuses the Realclimate contributors of being dishonest (not acknowledging their political activities) but that their activities contribute to the politicization of science; their activities are damaging science and, hence, they should behave differently.

Roger’s overall argument appears to be that as soon as a scientific topic becomes politically relevant, any public engagement related to that topic is immediately political. Most scientists would argue, however, that informing the public about a scientific topic is not inherently political, at least not in the sense of it being a form of advocacy; that would require having an explicit policy preference. In fact, most scientists would argue that it’s crucial that scientists engage publicly so that the public and policy makers can be suitably informed about a topic.

Of course, scientists who engage publicly should be clear about the role that they regard themselves as playing. There’s nothing wrong with a scientist advocating for something specific as long as they make clear that they’re presenting their own views about a topic, rather than presenting some kind of summary of our scientific understanding.

So, my general view of these science police type arguments is that they almost do what they claim others are doing; rather than engaging with one’s critics, it’s an attempt to deligitimise them by suggesting that they’re trying to close down/control the discussion. It’s unfortunate, because some of those being criticised do cover topics that are worth discussing, and do have some interesting views. However, rather than considering what their critics are saying, they seem to prefer spending their time complaining about how they’re being treated, while appearing to avoid considering that maybe the responsibility lies mostly with them. If your critics are having success, yet you regard what you’re saying as consistent with the evidence, then maybe you need to find a way of saying it that is still consistent with the evidence, but that is harder to criticise?

Posted in Climate change, ClimateBall, Research, Roger Pielke Jr, Science, Scientists, The philosophy of science, The scientific method | Tagged , , , , , | 57 Comments


I’ve been away for a week (more about this later, maybe), so haven’t had a chance to post anything. It has been a fairly warm week here in the UK, so it’s seem worth mentioning a recent paper about the global risk of deadly heat. It’s been covered already by Carbon Brief, so I don’t need to say much (I’ll probably fail).

Credit: Mora et al. (2017)

A key point is illustrated in the figure on the right, which shows temperature and relative humidity. The black crosses shows temperature and relative humidity during events that were lethal. The blue line shows the likely boundary between lethal and non-lethal events, and the red line is a 95% probability threshold (which, I think, means almost certainly deadly). Our body (in fact, any mammal’s body) generates heat, and the ability to transfer that heat away depends on temperature and relative humidity, and there is a combination of temperature and relative humidity above which it is no longers possible to do so. As the paper says

The fact that temperature and relative humidity best predict times when climatic conditions become deadly is consistent with human thermal physiology, as they are both directly related to body heat exchange. First, the combination of an optimum body core temperature (that is, ~37<supoC), the fact that our metabolism generates heat (~100 W at rest) and that an object cannot dissipate heat to an environment with equal or higher temperature (that is, the second law of thermodynamics), dictates that any ambient temperature above 37oC should result in body heat accumulation and a dangerous exceedance of the optimum body core temperature (hyperthermia). Second, sweating, the main process by which the body dissipates heat, becomes ineffective at high relative humidity (that is, air saturated with water vapour prevents evaporation of sweat); therefore, body heat accumulation can occur at temperatures lower than the optimum body core temperature in environments of high relative humidity.

The Carbon Brief article does highlight some criticisms of this study (the available data did not cover all parts of the world, for example). However, it does seem clear that if we continue to emit CO2 into the atmosphere, we will continue to warm and a larger fraction of the world (and a larger fraction of the world’s population) will experience heatwave conditions (combinations of temperature and relative humidity) that could be deadly.

This is a key point, though. How these conditions will change in the future will depend on what emission (and, hence, concentation) pathway we actually follow. Climate change isn’t guaranteed to lead to a substantial increase in the probability of these conditions occuring; it largely depends on what we choose to do, or not do.

An adaptability limit to climate change due to heat stress (Sherwood & Huber 2009).

Posted in Climate change, Global warming, Science, Severe Events | Tagged , , , , , | 211 Comments

What does the Vostok ice core tell us?

Euan Mearns, who runs a blog called Energy Matters, had a post in 2014 about The Vostok ice core: Temperature CO2 and CH4. This post has apparently had 8000 reads, is probably one of the most read texts on the subject, and yet, according to this post,

the Climate Science community continues to ignore the fairly profound implications of what the data actually shows.

The key issue appears to be a lag between temperature changes and CO2/CH4 changes that led Eaun to conclude that

variations in CO2 and CH4 are both caused by global temperature change and freeze thaw cycles at high latitudes. These natural geochemical cycles makes it inevitable that CO2 and CH4 will correlate with temperature. It is therefore totally invalid to use this relationship as evidence for CO2 forcing of climate, especially since during the onset of glaciations, there is no correlation at all.


CO2 in the past played a negligible role. It simply responded to bio-geochemical process caused by changing temperature and ice cover.

I left a couple of comments, but only one has appeared, so I thought I would quickly write this post. The reason why the climate science community has probably ignored the profound implications in Euan’s posts is – I think – because they’re not really very profound. Firstly, this is data from a single site (Vostok). Even though greenhouse gases may be well-mixed, the temperature is not. You need to be a little careful when using this single site to infer something about global temperatures, and the relationship between temperature changes and CO2/CH4 changes. Maybe more importantly, though, what the data indicates is not really all that surprising.

It is certainly not the case that CO2 is the main driver of the glacial cycles. The trigger for the glacial cycles is probably orbital variations, in particular large changes in solar insolation at high northern latitudes. However, the net change in solar insolation (globally) is small, so it cannot – by itself – produce much in the way of warming/cooling. What is thought to happen is that these changes trigger either ice sheet retreat, or ice sheet advance (depending on whether we’re moving into a glacial, or out of a glacial). This changes the planetary albedo which produces either warming (ice sheet retreat) or cooling (ice sheet advance).

This warming/cooling then results in the release/uptake of CO2 from the oceans, and also influences vegetation (which itself produces an albedo change and releases, or takes up, CO2). The change in atmospheric CO2 (and CH4) then produces more warming/cooling, causes further retreat/advance of the ice sheets, and further changes in vegetation. These different processes (albedo changes and changes in atmospheric CO2/CH4) then together produce the temperature changes that move us into, or out of, a glacial period.

A key point is that CO2 does indeed respond to temperature changes (through ocean outgassing/uptake and changes in vegetation) and – in the context of the glacial cycles – is more properly a feedback, than a forcing. This, however, does not mean that it is not a greenhouse gas and that changes in its concentration in the atmosphere will not influence global temperatures (it clearly does). We really cannot explain the glacial cycle without including the influence of changes in greenhouse gas concentrations in the atmosphere.

This paper by James Hansen and Makiko Sato provides a nice explanation of the process and indicates that changes in atmospheric greenhouse gas concentrations (mainly CO2 and CH4) is responsible for about half of the glacial cycle temperature changes and that this is consistent with an equilibrium climate sensitivity of about 3oC ± 1oC. There are also a couple of nice Skeptical Science posts that discuss the whole CO2 lags temperature issue.

Of course, I’m not an expert on this, so may not have explained this as well as I could have. Also, maybe I have missed something and maybe what Euan Mearns has presented is indeed profound and should not be ignored by the climate science community. However, if I have learned something in my years as a research scientist; when you think you’ve discovered something profound and everyone else ignores it, maybe it really isn’t as profound as you initially thought.


Through the beauty of Twitter, people have provided some relevant references. Gavin Foster suggests that the newer West Antarctic Ice Sheet Divide Ice Core resolves some of the age issues. He also highlights this paper, the abstract of which says:

We show that although low-frequency CO2 variations parallel changes in Antarctic temperature, abrupt CO2 changes occur that have a clear relationship with abrupt climate changes in the Northern Hemisphere. …..We suggest that processes operating on centennial timescales, probably involving the Atlantic meridional overturning circulation, seem to be influencing global carbon-cycle dynamics and are at present not widely considered in Earth system models.

and this paper (which is discussed – I think – in the Skeptical Science posts I highlighted), the abstract of which says:

Differences between the respective temperature changes of the Northern Hemisphere and Southern Hemisphere parallel variations in the strength of the Atlantic meridional overturning circulation recorded in marine sediments. These observations, together with transient global climate model simulations, support the conclusion that an antiphased hemispheric temperature response to ocean circulation changes superimposed on globally in-phase warming driven by increasing CO2 concentrations is an explanation for much of the temperature change at the end of the most recent ice age.

Steve Forden also highlighted a paper that says:

The robust lead of Antarctic temperature over CO2 concentration during several recent glacial–interglacial transitions inferred from the Antarctic ice cores apparently contradicts the concept of CO2-driven climate change and still remains unexplained……….our results provide an explanation for the observed Antarctic temperature lead over CO2 concentration. It is shown that the interhemispheric oceanic heat transport provides a crucial link between the two hemispheres. We demonstrate that temporal variations of the oceanic heat transport strongly contribute to the observed phase relationship between polar temperature records in both hemispheres……Based on our results, we argue that the analysis of leads and lags alone, without a comprehensive understanding and an adequate model of all relevant climate processes, cannot provide direct information about causal relationships in the climate system.

And another couple of papers, thanks to Twitter. Does seem as though this isn’t really being ignored.

Eric Steig (who is one of the PIs of the WAIS Divide Ice Core) has highlighted a couple of other papers in this comment. In particular, Pedro et al. (2012), which says:

we show that the increase in CO2 likely lagged the increase in regional Antarctic temperature by less than 400 yr and that even a short lead of CO2 over temperature cannot be excluded. This result, consistent for both CO2 records, implies a faster coupling between temperature and CO2 than previous estimates, which had permitted up to millennial-scale lags.

There are also two Realclimate posts that cover this issue, and another Skeptical Science post.

Posted in Climate change, Climate sensitivity, ClimateBall, Global warming, Greenhouse effect, Pseudoscience, Research, Science | Tagged , , , , , | 72 Comments


Peddling is arguably the most favorite way for contrarians to lob factoids behind enemy lines. Once a door opens, peddlers block it with their foot and dispatch their sale pitches. Peddled talking points seldom matter to the topic at hand, i.e. they’re red herrings, or as I prefer to call them squirrels, because “look, squirrel!,” because the verb squirreling,  and because Rachel.

Responding to the peddler’s talking point only opens other doors. A flurry of squirrels get thrown on the field, exchanges go in many directions at the same time. At best we get constructive brainstorming, at worse a food fight. In any event, the Gods of ClimateBall (tm) rejoice.

Since language is a martial art, peddling can start anywhere and about anything. I recently experienced one with Freedom Fernando, after I dared to retweet a tweet telling that that some were burning food in Brazil. Fernando’s peddling move was his famous “but Venezuela”:

My response abides by the principle: A Squirrel for a Squirrel.  It also conveys that I don’t mind discussing the historical reasons why many South American countries became allergic to the Washington Consensus. I could have pointed out that famines correlated more with mismanagement and political conflicts than ideology, but baiting Fernando with a Marxian source was too tempting. At least twenty-seven tweets followed. There could have been more, but I decided to write this instead.

Fernando doubled-down his peddling by denying that Venezuela had economic sanctions. In return, I cited an official webpage of the US Government describing these. Then it got interesting.

A Think Tank Tie (see the mug face below) chimed in to say that the sanctions did not target Venezuela per se, but individuals. My first response recalled that this point was an ignoratio elenchi:

As if warning against doing business in Venezuela wasn’t a most effective way to put economic pressure on a country. (Many hold that official sanctions are inefficient at best.) As if the Iran sanctions couldn’t affect Venezuela. As if there wasn’t any underhanded ways to expand one’s country’s influence. As if any of this was relevant to my point anyway.

Then it gets surreal: Fernando accuses me of backing up a genocide. A genocide, no less. Qui ne dit mot consent, I suppose, so I reject his accusation and call him on his peddling. Instead of owning it, Fernando doubles down by blaming me for having provoked his peddling!

To show Fernando that I could not care less about ideology, I showed him the historical prices of oil between 2008 and 2014. The correlation between low oil prices and increase in Venezuelian suffering should be obvious to anyone. Our Think Tank Tie resurfaces, moving the goalpost using a “what about question.” I remind him of whataboutism while clarifying that the chart wasn’t meant as an explanation of the crisis:

Our Think Tank Tie then gets personal, which backfires quite quickly since he can’t commit to the crap his think tank peddles. Nevertheless, Fernando’s peddling succeeded. Squirrels were thrown. Nothing got resolved. Everybody left happy.

THE END? No, not at all. Like auditing, peddling never ends.

Posted in ClimateBall, Freedom Fighters | Tagged , , | 58 Comments

Climate communication

Doug McNeall recently gave a talk about surviving the climate communication environment, which he discusses in this post. A lightly edited version of the slides are available here. The slides, of course, don’t tell you precisely what was said in the talk, but I find little to disagree with. The environment can be difficult and challenging; we should try to say interesting things but also be careful of what we say; it should be relevant but not too complex; we should know the audience, and we should repeat the message.

One thing I will say is that Doug’s slides illustrate the apparent conflict between the deficit model and the cultural congnition model. I think such a conflict does exist, but I’ve never been sure why it needs to exist. It seems that there are some who are pre-disposed to reject certain information and that it’s extremely difficult to communicate effectively with such people if they don’t identify with you in some way. Therefore, some people (Katherine Hayhoe, for example) can be more effective communicators in some situations, and we should – in my opinion – encourage and support those who are capable of reaching people who might preferentially reject the information that’s being presented. However, this doesn’t mean that there is no place for those who simply see themselves as presenting information, rather then explicitly trying to reach certain groups. I don’t see a good reason why the deficit model and cultural congnition couldn’t be seen as complementary, rather than in conflict.

However, Doug’s post highlighted that some (mainly female scientists) are choosing to no longer engage on social media because of the harassment that they receive. This isn’t simply it being unpleasant, but is a level of harassment that is genuinely disturbing and that noone should be expected to endure. Doug asks what can be done about this, and I don’t have any good answers; it’s something that really shouldn’t happen, but clearly does. I also find it difficult to comment on something I’ve never experienced, and almost certainly will never experience.

All I can think of suggesting is based partly on a series of tweets from Jacquelyn Gill. Maybe we should try to continually remind ourselves that science communication can be difficult, that we can all do better, but that we should also try to support those who are engaging publicly and – when appropriate – promote what they’re doing. This doesn’t mean not correcting people when they make a mistake, or not suggesting ways in which they could do better; we just need to try and be constructive, and positive, when we do so (and, similarly, responding positively when people provide constructive criticism).

I really don’t have any suggestions as to how to deal with the harassment that some experience, but maybe we do need to try and remember how isolating social media can be and try to be more supportive of those who are engaging publicly. It won’t somehow negate the appalling harassment that some experience, but at least it shouldn’t make it worse. I know it’s not enough, and maybe it’s not even really a start, but it’s all that I can think of and it’s all that I think I can do. Maybe others, however, have better suggestions.

Posted in Climate change, ClimateBall | Tagged , , , , , , | 96 Comments