2017: A year in review

I’ve now been writing this blog for almost 5 years and I still don’t quite know what I’m trying to achieve, if anything. Hopefully a blog that presents a reasonable representation of our current understanding of climate science, while also sometimes presenting my own views about this – and other – topics.

Anyway, I thought I would briefly highlight some of this year’s posts.

January saw an attempt to explain the residual airborne fraction and a guest post by Patrick Brown discussing Pat Frank’s ridiculous claims that propagation of error calculations invalidate climate model projections.

February included an expose about David Rose not understanding baselines, a post about William Happer not even giving physicists a bad name, and a guest post by Zeke Hausfather about baselines and buoys.

March saw posts about Matt Ridley’s response to Tim Palmer’s talk about hoax, catastrophe, or just lukewarm, and a post about a potential feedback paradox (partly motivated by Judith Curry’s continual claims that maybe a large fraction of the observed warming could be natural).

April included posts about David Whitehouse appearing to suggest that it’s okay to lie, a post about Roger Pielke Jr. metaphorically throwing his toys out the pram, and another post about reconciling ECS estimates.

May had a post about our new consensus paper, a suggestion that OMICS will publish anything, and what turned out to be a contentious one about deficit model thinking.

June was a reasonably quiet month with a post about the resurgence of Lukewarmers and a post about the Vostok ice core (motivated by a rather confused post by Eaun Mearns on Energy Matters).

July discussed David Whitehouse’s continued confusion, a guest post by Michael Tobis about the red team, blue team idea (suggesting that the only way not to lose is to play), and a discussion of Warren Pearce, Reiner Grundmann and colleagues’s paper on going beyond climate consensus.

August’s highlight was probably the post discussing Ned Nikolov and Karl Zeller’s paper about pressure determining surface temperatures (it doesn’t), but also included a post about Kevin Anderson’s numbers (which turned out to be more contentious than expected) and a post about STS being all talk and no walk (which discussed a Steve Fuller paper which seemed to suggest that STS should be proud of their role in enabling post-truth).

September saw a retrospective about my time engaging online (motivated by something similar written by Philip Moriarty), a brief memorial to Andy Skuce (who passed away this year), a post about the Global Warming Policy Foundation (GWPF) playing climateball (badly), and a discussion about carbon budgets (motivated by the Millar et al. paper on achieving the 1.5o target).

October had another post about committed warming (one of my themes), a post about a comment we published in response to Hermann Harde’s incorrect paper about the carbon cycle, a post about cloud feedbacks and one I quite liked about the Virial Theorem (also intended as a reponse to Ned Nikolov’s incorrect assertion about how surface temperatures are enhanced).

November had some rather active posts. One of them discussing whether or not Jordan Peterson speaks the truth, a guest post by Karsten Haustein discussing their real time global warming index, a post about Roger Pielke Jr’s rather confused Mertonian norms inferences, and another highlighting Katharine Hayhoe’s presentation in Edinburgh.

December has seemed rather quiet. There has been an active post about Polar Bears and Arctic sea ice (discussing the Harvey et al. paper about some blogs focussing mainly on Susan Crockford’s work), a post discussing arguing about the greenhouse effect (again), and – most recently – a post about Judith Curry’s apparent ability to communicate publicly without advocating.

Well, that’s ended up slightly longer than intended. I don’t know what next year will bring, but probably something similar to this year – I don’t have any plans to make any changes, although I am finding more and more difficult to find things to write about. All I need to do now is wish everyone all the best for the new year.

Posted in Climate change, ClimateBall, Global warming, Greenhouse effect, Personal, physicists, Pseudoscience, Roger Pielke Jr | Tagged , , , , , , , , , , | 30 Comments

Political activism

There’s been a rather lengthy Twitter exchange involving Judith Curry, mostly focusing on whether or not Judith is a political activist. Judith appears to be suggesting that what she does is not political activism, or any form of political advocacy, saying, for example

If one defines political activism as some kind of direct, potentially confrontational, activism in support for, or against, a cause, then this may be true. It would then, however, imply that few are doing so. What most who were engaging with Judith were trying to suggest is that any form of public engagement that could potentially influence policy is a form of activism/advocacy.

Writing a blog about a policy relevant topic, as I do, would certainly seem to qualify. I write this because I think this is an important topic that I wish were better understood and better accepted, so that we could make more informed decisions as to what we should, or should not, do. I don’t have strong views as to what we should do specifically, but I think continuing to simply pump CO2 into the atmosphere is a bad idea and that we should find ways to reduce our emissions, eventually getting them to zero. If pressed as to what we should do more specifically, I would say a carbon tax. I’m not convinced that will be enough by itself, but it would certainly seem to be good way to proceed.

Judith also writes a blog about a policy relevant topic, and – in addition – has testified before the US House of Representatives and has authored a report on climate models for a policy foundation. There were also plenty of other examples provided on Twitter. Yet Judith still seems to object to others describing what she does as a form of political activism.

The problem, though, is not that Judith undertakes a form of political advocacy, it’s that she denies it. There’s nothing wrong with engaging in public discourse about a policy relevant topic. However, doing so while suggesting that what one does is not a form of advocacy implies a completely unrealistic sense of objectivity and lack of bias. Anyone who engages publicly will put their own spin on what they present. Ideally, they do so while also doing their best to place it into the overall context; in principle they should acknowledge if what they present is substantively different from a consensus position, if such a position exists. This, in my view, is the real issue with how Judith engages.

It’s pretty clear that Judith holds a position that is at odds with most other experts in the field and presents information that is not consistent with the available evidence. In fact, from what I’ve seen, a great deal of what Judith presents is based more on her opinions, than on any kind robust scientific analysis. To do this, while claiming to not be engaging in policy advocacy, illustrates either a remarkable lack of awareness, or a willful disingenuousness. There is nothing wrong with political advocacy/activism. What is wrong, in my view, is to publicly present a policy relevant, minority view, while claiming that what you’re doing is not activism/advocacy, especially if you also claim that what others are doing is.

Gavin Schmidt on advocacy. (Gavin Schmidt giving the AGU Stephen Schneider lecture).
Science and silence. (A post about some of Judith’s comments on advocacy).
The road to hell. (A post about some of Judith’s comments on Research integrity).
Hearing about climate science and the scientific method. (A post about Judith’s testimony to the US Congress).
I also don’t get Judith’s logic. (A post about Judith’s logic with respect to the IPCC attribution statement).

Posted in advocacy, ClimateBall, Gavin Schmidt, Judith Curry, Policy, Politics | Tagged , , , , | 257 Comments

Merry Christmas, etc

Since it’s now the afternoon of Christmas Eve here, it would seem time to quickly wish everyone a Merry Christmas, or whatever season’s greeting is most suitable. I certainly plan to have a few days relaxing with the family, so don’t plan to write any posts and will endeavour to mostly stay off Twitter. I hope everyone manages to have a pleasant and enjoyable break. I may write a brief post summarising the year, but otherwise I’ll be back in the new year.

Credit : xkcd.

Posted in Personal | Tagged , , | 24 Comments

Galactic cosmic rays

There’s a recent Nature Communications paper by Svensmark et al. called [i]ncreased ionization supports growth of aerosols into cloud condensation nuclei. The basic idea is that cosmic rays (energetic particles typically accelerated by shock waves) can influence the growth of aerosol particles that can then act as cloud nucleation sites. This may, therefore, play some kind of role in climate change.

The problem is that this idea has been around for quite some time and has essentially been pre-bunked. There’s a relevant Realclimate review called a cluttered story of little success. In fact, if you search Realclimate for Svensmark, you get a number of posts that cover this topic.

There have also been recent CERN results which suggest that the Sun-clouds connection takes a beating. The new paper has also not be all that well received.

It did, however, remind of something that I thought I would add here. I used to work with someone called Gary Zank, who was involved in research that was used to suggest that maybe dinosaurs were wiped out by genetic mutations from cosmic rays. The basic idea is that the Sun has a wind that blows a bubble of magnetised plasma – called the Heliosphere – into the interstellar medium. This acts to shield the inner Solar System from galactic cosmic rays.

However, the Solar System actually moves through the interstellar medium. The size of this bubble depends on the density and temperature of the local interstellar medium. Currently we’re in a warm, diffuse region, and so the bubble extends out to well beyond Pluto. However, when we are in a cold, dense region, it may only extend to about the orbit of Jupiter; much smaller than it is today. This would mean that the local cosmic ray flux would be much higher than when the bubble is larger. It is thought that we were in a denser region about 66 million years ago and, hence, maybe the enhance cosmic ray flux wiped out the dinosaurs.

I don’t think that is really regarded as a viable explanation. However, it does suggest that the local cosmic ray flux could vary quite substantially on these timescales. If cosmic rays can play a role in cloud formation, and hence our climate, you might expect to see some kind of signal in our past temperatures. I even found a paper that discusses exactly this, saying

We have demonstrated that the cosmic ray spectra at the Earth, particularly that of anomalous protons can vary by
orders of magnitude even for moderate changes in the interstellar medium……The assumed changes
in the state of the interstellar medium certainly occur along the galactic orbit of the Sun on time scales of a few thousand to a few million years. In conclusion, we state that, on these time scales, if the cosmic ray–climate link will be confirmed, one should consider an effect of interstellar–terrestrial relations on the climate on Earth.

As far as I’m aware, there is no indication of such a signal in our past climate. If, as suggested above, the cosmic ray flux vary by orders of magnitude, you might expect such a signal to be easy to find.

It seems highly unlikely that any cosmic ray effect on clouds (if there even is one) can be large enough to be climatically relevant. As far as I can tell, this recent paper is simply another attempt to suggest that our climate is somehow very sensitive to small changes in something that isn’t CO2 so as to imply that maybe it isn’t sensitive to much larger changes in CO2 itself.

Something I meant to include in the post, but forgot to do, was to point out something odd about Svensmark et als. reference list. This comes from a post by Ari Jokimaki. They do not cite a paper by Kulmala et al. called Atmospheric data over a solar cycle: no connection between galactic cosmic rays and new particle formation , but do cite earlier papers by the same author. As Ari points out, Svensmark et al. seems to ignore a number of recent papers that appear to contradict what they’re suggesting in this new paper.

Posted in Climate change, Climate sensitivity, ClimateBall, Global warming, Science, Sound Science (tm) | Tagged , , , , , , , | 10 Comments

Arguing about the greenhouse effect – again

There’s been a rather lengthy Twitter thread about the greenhouse effect. In particular, focusing on claims that there is no such thing. Of course, engaging in such discussions so as to actually change anyone’s minds is pointless. However, I think there is still merit in pointing out the errors in what some are suggesting (if only for the benefit of some onlookers) and it can be moderately enjoyable (in the sense that you’re forced to think about how to present your arguments, and that can be challenging).

There are, however, a couple of things that I found quite remarkable. One is how comfortable some are in being compared to great scientists of the past who have been instrumental in over-throwing paradigms. They certainly don’t let humility get in the way of progress. The other is how quickly it becomes clear that they’re really arguing against a simplistic caricature of the greenhouse effect. I’ve certainly encountered this on a number of occasions before.

There are many ways to explain the greenhouse effect, but in a simple sense it is simply that the atmosphere is mostly transparent to incoming solar radiation, while being opaque to the outgoing longwavelength radiation coming from the surface. This causes the surface to be warmer than it would otherwise be.

There are a number of basic consequences of the greenhouse effect. One, for example, is that thespectrum we would observe from space has various features associated with the absorption of outgoing radiation. Also, we would expect to see downwelling longwavelength flux at the surface.

What’s remarkable is that these all seem to be things that those who dispute the greenhouse effect accept. However, they don’t seem to regard these as indications of a greenhouse effect. The problem, though, is that if there is no atmospheric greenhouse effect, then the atmosphere should be radiatively inactive and we should not observe any atmospheric absorption in the outgoing spectrum, or any downwelling longwavelength flux. Accepting these observations, while disputing the greenhouse effect, is therefore rather inconsistent.

So, it seems that at least some who dispute the greenhouse effect accept most of the observations that would be regarded as confirming it. I would like to think that this is simply because they’re confused, but I suspect it is strongly influenced by what accepting the greenhouse effect would imply.

Posted in Climate change, ClimateBall, Greenhouse effect, Science | Tagged , , , | 76 Comments

What if global warming ends up being greater than we thought?

I recently wrote a post about the Brown & Caldeira paper which suggests that climate sensitivity may be on the high side of the range. Rather predictably, Nic Lewis has a guest post on Climate Etc in which he looks at the Brown & Caldeira analysis and claims that global warming will not be greater than we thought.

I think this claim is simply wrong. Even if he has found some issue with the analysis in Brown & Caldeira, that still would not justify a claim that global warming will not be greater than we thought. At a basic level, all that the Brown & Caldeira paper is suggesting is that the models that most closely match some observed properties of the climate system tend to have climate sensitivities on the high side of the range. This also isn’t the first time this has been suggested.

One could argue that there are also studies that suggest that climate sensitivity could be on the low side of the range. Also, as Ray Pierrehumbert says in this comment, it’s not necessarily the case that models that do best at representing short-term fluctuations will also do best when it comes to the feedbacks that determine ECS. One might then argue that we should really just stick with something like the IPCC range for climate sensitivity; it is almost certainly a reasonable representation of what is likely.

The debate, in my view, therefore should not really be about whether climate sensitivity could be high, or low, but what we should do in case it is high (which, to be clear, is not to say that people shouldn’t study this). The impact of climate change almost certainly increases with warming and, if we can quantify this impact, probably increases non-linearly. In other words, the impact of 3oC of warming is likely to be more than twice as great as the impact of 1.5oC. If addressing climate change carried more risks than the risks associated with climate sensitivity being high, then maybe we would do nothing and hope it was low. This, however, seems very unlikely.

One of the key things is simply to emit less CO2 into the atmosphere than we could, and this seems quite possible, if maybe not easy. There are many possible ways to do so and if one is concerned about big government and too much regulation, then just promote something like a carbon tax. Even if you’re not particularly concerned, one could still consider that an economically optimal pathway suggests peaking emissions by about 2040 and not increasing them much between now and then (see Figure 2).

Unless one assumes that climate sensitivity is very low and ocean acidification will have no adverse impacts (and there’s a word for those who think this), I can’t see a scenario under which we shouldn’t be thinking about how reduce our emission of CO2 into the atmosphere. The irony, I think, is that what probably leads people to avoid considering ways to reduce our emissions (big government, too much regulation, interfering in the market,….) is precisely what we will get if climate sensitivity does turn out to be high and we decide, in the future, that we need to rapidly reduce our emissions. This doesn’t seem very sensible.

Posted in Climate change, Climate sensitivity, ClimateBall, Global warming, GRRRROWTH, Science | Tagged , , , , , , | 71 Comments

More about Equilibrium Climate Sensitivity

It’s currently the AGU Fall Meeting and there was a session on Climate sensitivity and feedbacks. It included talks by Kate Marvel and Kyle Armour, and I noticed that the Convener, Andrew Dessler, had tweeted

This is something I’ve written about a number of times and it does now seem that there is mostly agreement that the observationally-based estimates are not really indicative of a lower equilibrium climate sensitivity (ECS). There are a number of reasons (that I try to elaborate in some of my earlier posts) but as Kate Marvel says in her summary it’s essentially that

You might think we could estimate this from observations: we’ve emitted carbon dioxide, and the temperature has risen. But the future may differ from the past, and there’s reason to think that the warming we’ve experienced so far is different from the warming to come.

An additional factor can also be the method, in particular the choice of prior. James Annan has a recent post in which he uses a different prior to that used in some of the other analyses. It produces a 5-95% range of 1.2oC – 4.8oC, which seems mostly consistent with the IPCC range of 1.5oC – 4.5oC (which is – I think – more properly a 17-83% range). The best estimate is 2.1oC, which is maybe still a bit lower than other estimates, but still seems reasonable.

Maybe I’ll finish this post by also mentioning the recent Royal Society report which also says

value below 2oC for the lower end of the likely range of equilibrium climate sensitivity now seems less plausible.

Posted in Climate sensitivity, Global warming, IPCC, Science, The scientific method | Tagged , , , , , , | 33 Comments