Addicted to Watt!

Despite my rather unpleasant encounter with another commentator on the Watts Up With That site, I find myself slightly addicted to going back and checking for new posts and comments. It’s not because I enjoy it. I think it’s because I’m still slightly shocked about the encounter I had a few days ago and just wanted to see if such encounters are common or not. I didn’t search very hard, but I did find a number of fairly aggressive exchanges between some commentators.

What I found most “interesting” is the style of the rhetoric. Quite a few posts were extremely condescending and regularly seem to contain things like “couldn’t stop myself from smiling/laughing/grinning at how silly” some climate scientist had been. On almost every single post, the first set of comments would invariably be short, snappy, snarky, sarcastic remarks about how idiotic or stupid a particular study had been. It seems like an online version of mob rule. A classic example of confirmation bias. Noone who was critical of a some piece of climate science ever seemed to say “… but this aspect of the work looks interesting.” It was almost always complete dismissal. If this really is a group of people who claim to be interested in engaging in scientific discussions to better understand the science of climate change, they’re certainly going about it in a way that I don’t think any scientist I know would recognise as suitable.

There also seem to be some commentators who dominate the discussions. The one I encountered (richardscourtney) seems to be held in quite high regard. The impression I have is that he sees himself as some grand figure who is there to clarify things for those who are uncertain about something, and to challenge those – in the interests of science – who make statements with which he disagrees. His style of rhetoric is regularly aggressive but also extremely sarcastic. Thanking people for responding to something and then launching into some attack on what’s been said. What’s ironic, is that he often claims to be challenging unsubstantiated statements by making mostly unsubstantiated statements of his own. It’s as if by saying something forcefully and definitely it makes his statement true, while another person’s statements are somehow anti-scientific nonsense. His comments also have lots of “NO!” and boldface words to, I assume, make his statements more authoritative.

One of the common themes on the Watts Up With That site is that there is something fundamentally wrong with climate scientists. They’re either lying, or incredibly stupid, or naive, or subconsciously influenced by some inherent bias in the climate science community. They simply can’t be trusted and need to be constantly mocked or verbally abused! I was interested to see a post claiming that Weather – not climate – caused the brief surface melt in Greenland last summer. This paper was quite well received. The lead author on the paper was Ralf Bennartz, a Professor at the University of Wisconsin. I then discovered another post called Old models do a bad jobs so a new models says “warming must be worse”. This was about a paper describing attempts to include – more realistically – the influence of clouds in climate models. This post seemed to have the normal level of mockery, and the comments seemed to be particularly dismissive of this work. But hold on a minute, one of the authors seems to be the same Ralf Bennartz who was lead author on what was an acceptable paper suggesting that weather, not climate, influenced ice cover in Greenland last year. I’m not suggesting that you’re not allowed to criticise one paper by a particular person while regarding a different of their papers as being quite good. What I do think, however, is that you can’t accuse climate scientists of being inherently dishonest and then regard positively a paper by a climate scientist if it happens to say something that suits your ideology.

Now, I imagine that if any credible scientists were actually to read this post, they would probably think – “did you expect it to be different?”. Well, I’ve read enough about climate change to have been aware that this was a distinct possibility. I think I had hoped that maybe it would be possible to engage with climate skeptics in a manner that was at least consistent with decent scientific discourse. I don’t think you need to change someone’s mind in order to make such an exchange worthwhile. It does seem, according to my experience at least, that this is virtually impossible on the Watts Up With That site. I should acknowledge that there may well be other sites that support the results of climate science on which it would also be difficult. That, however, doesn’t excuse the behaviour of those on the Watts Up With That site. The other thing I would say is that I don’t like the idea of being criticial of something without at least having some personal experience that justifies such a criticism. Having both read a number of posts and a large number of comments on the Watts Up With That site, and after a rather unpleasant exchange with one of their regular commentators, I certainly feel justified in being highly critical of the manner in which the site both presents and discusses climate science. It’s quite amazing that it seems to have won a “Best Science Blog” 3 times. Just as many scientists would be happy to acknowledge that the paper with the most citations isn’t necessarily the best paper, I suspect that many would also agree that winning a “Best Science Blog” award doesn’t guarantee that you’re actually the best science blog. I certainly hope that’s the case because heaven helps us if this is indeed the best science blog.


What’s up with that?

For a while now I’ve been reading posts on Anthony Watt’s blog, Watts Up With That. This is a site that is extremely skeptical (to put it mildly) that man is having any influence on our climate and often claims that Anthropogenic Global Warming is a conspiracy put forward by climate scientists. Just in case you’re not familiar with my other posts, I am not particularly skeptical of the results of climate science. Let my also clarify why I write it that way. I’m a scientist, therefore skepticism is a good thing. As with any science area (particular ones that relate to very complex systems) I’m sure that there are aspects of climate science that will turn out to be wrong or have some kind of error and that the models will change as more data is collected and as more techniques are developed for determining past temperature histories.

Anyway, so I started making a few comments on the Watts Up With That site. I commented on a post by Nancy Green, called Marcott – 3 spikes and you’re out, which was using an analogy between astronomers detecting planets around other stars and the ability to detect warm periods of less than 300 years in the Marcott et al. (2013) data. To be fair, I initially misunderstood the analogy being used and was happy to acknowledge this when corrected by another commentator. I don’t think that an analogy really proves a scientific point and I think that the post missed that even though the resolution of the Marcott et al. (2013) data is – when smeared – about 300 years, this doesn’t mean that warm periods that are shorter (but comparable) would have no effect whatsoever.

I then made a comment on a post titled On Guemas et al. (2013) “Retrospective prediction of the global warming slowdown in the past decade”. This post referred to the abstract of a recent paper. The abstract indicated that the paper is about a new model that supports the idea that the reason that the global surface temperatures have risen more slowly than expected (or more correctly, that there hasn’t been a statistically significant increase in surface temperatures since the mid 1990s) is because energy has been going into the oceans. The abstract then uses the term “retrospective prediction”.

Many of the comments that followed seemed to mockingly dismiss the term “restrospective prediction”, suggesting that it’s easy if you already know the answer. I then commented that this was a little surprising given that retrospective prediction was just basically asking the question “what would my model have predicted had I only used data up to some point in the past” and then comparing what it predicts with what actually happened. It seemed like a pretty innocuous comment. I wasn’t commenting specifically on the paper. I wasn’t commenting on climate science as such. I was commenting on what seemed to me to be a pretty standard practice in many areas of science. I didn’t even suggest that the authors of the paper in question had done this properly or even suggest that their model had any merit or not. I ended a bit provocatively by suggesting that mocking such a process either indicated ignorance or a bias against anything with which the commentators disagreed. In a sense, I had intentionally chosen to make a comment that shouldn’t really be all that controversial. People could agree with it without having to change their views about climate science.

I had a few responses, one of which actually acknowledged that it was a fair point. However, I did get one response from someone using the name richardscourtney. I assume that this is the same Richard S Courtney mentioned in DeSmogBlog. I don’t know for certain that it is, but it seems that it may well be. I appreciate that I blog anonymously, so I aim to refrain from making any personal comments about this individual. Everything I say from now on is my opinion of something that, currently, is in the public domain.

This person’s comment was extremely forceful. It claimed that what I had said was ridiculous and an example of pseudo-scientific nonsense. I responded very briefly by saying that their comment was “Interesting” and that I would say “no more”. They then responded by saying that they knew why I wouldn’t respond and everyone else will too. I pointed out that they probably did not know. It certainly wasn’t that I couldn’t think of a suitable response; it was based on a sense that there wasn’t much point engaging if I was unlikely to learn something and if the other party seemed unwilling to consider learning anything either. I don’t think anything I had said was particularly insulting and I made sure to make it clear that what I was saying was an opinion, rather than a fact. This commentator then continues by accusing me of being an anonymous troll posting “untrue nonsense”. The next few comments then get even more vitriolic insisting that I apologies for my unscientific statements. After a few more exchanges (in which I think I maintain an element of decorum while being robust) his final statement is that I came there as a troll to “mislead”, “misinform” and “disrupt”. That he is interested in “promoting science” and that he will “expose psuedo-scientific nonsense” when used to “attack science”. Unless they get removed, you can follow the link to the post in question, read them yourself, and make up your own mind.

I found this all quite remarkable. To be accused of attacking science simply because I wouldn’t respond to what was essentially an attack on my initial comment was amazing. The irony of someone insisting that I apologise for a comment while at the same time accusing me of being anti-scientific. In some sense, I’m still not quite sure what to make of this. To a certain extent, I find it quite disappointing. I don’t agree with much of what is written on the Watts Up With That site, but that doesn’t mean that I think it shouldn’t be written. Also, although I expected some robust discussions if I did make comments on the site, I didn’t quite expect anything like this. I specifically chose to make comments that I thought would not be particularly controversial. I was reasonably robust in some of my responses to richardscourtney, but said nothing that was specifically insulting and was always open to the possibility that they might rein in their rhetoric slightly. In fact, I’ve had discussions of this kind before and normally both parties start to tone things down in the hope that some kind of agreement could be reached. This just seemed to be escalating. I have since found this post called The continuing misadventures of Richard S Courtney: (Non) Scientist. This seems to suggest, if richardscourtney is indeed Richard S Courtney, that this is his normal style of engagement. It also suggests that he may not be entirely honest about his scientific credentials – although I have no idea if this is true or not.

The person called richardscourtney wanted me to respond to their comment, which I refused to do. I will, however, comment below and they are welcome to respond if they ever encounter this post. I have never moderated a comment before and would like not to have to do so. I will allow some leeway but will moderate anything that is particular offensive or insulting. Here is my basic response.

Firstly, the response by richardscourtney had very little to do with what I had actually said in my original comment. The response refers to a difference between a model prediction and observed reality suggesting a flaw in the model. I made no mention of how well the model represented reality. I was not, specifically, referring to what had been done in the Guemas et al. paper. How could I? All we had was the abstract. My point was very simply that if you develop a model that you wish to use to predict the future evolution of something, it is entirely reasonable to consider how it would have performed in the past. Consider a hypothetical situation in which we have data for something from some initial time up until 2013. To test the model, use data only from before (for example) 1990 and then use your model to predict what would happen between 1990 and 2013. This can then be compared with what actually happened. This is not pseudo-science. It is a perfectly reasonable way to test a model.

What do I make of all this? I think what I was hoping was that someone else might step in and try to defuse the situation slightly. Surely some of the other commentators would like the site to include robust but decent debates that don’t include accusation of trolling and claims that what’s been said is pseudo-scientific nonsense. If others on that site think that this type of exchange is appropriate, then that says more about their credibility and decency than about mine. In general I think Anthony Watts’s views about climate science and global warming are generally wrong, but I always thought that he was at least willing to engage in a manner that was conducive to a reasonable debate. If he condones such behaviour on his blog, then I certainly don’t think that he can claim to be genuinely interested in finding out the “truth” about the science of climate change.

Pressure on Venus

I’ve written before about the Runaway greenhouse process on Venus. In the case of Venus, this was an entirely natural process and such a process is unlikely to take place on Earth as we have locked much of our CO2 into carbonate rocks. It is, however, illustrative of how the greenhouse effect can significantly influence the climate on a terrestrial planet.

I recently became aware of a post on the Watts up with that website claiming that the reason Venus has such a high surface temperature is because of the extremely high pressure. There are lots of equations and graphs and quite a convincing argument, but it is simply wrong. The reason I thought I would write about this is that when I saw that post I remembered a senior Professor in an Earth Science department at a US university telling me the same thing a few years ago. At the time I thought, “that’s interesting”, but didn’t think any more of it. If a professor of Earth science can get it wrong, no wonder it’s easy enough to make it seem as though the argument makes sense.

So why is it wrong. Basic atmospheric modelling is not all that difficult. To model an atmosphere you need an equation of state relating pressure, density and temperature. Typically you would use something like
where P is the pressure, ρ is the density, T is the temperature, mH is the mass of a hydrogen atom, and μ is the mean molecular weight. On Earth, the most common molecule in the atmosphere is N2 so μ ~ 28, while on Venus it is CO2 so μ ~ 44.

Atmospheres will settle into a state of hydrostatic equilibrium. This means that the downward force of gravity will be balanced by an upward pressure force. This allows us to write
where g is the acceleration due to gravity (9.8 m s-2 on Earth and 8.9 m s-2 on Venus) and z is the height in the atmosphere. We can solve the above equation to write
where Po is the pressure at the base of the atmosphere. The term kT/μmHg is known as the scaleheight and tells you the vertical distance over which the pressure drops by a factor of 1/e (1/2.72). It increases with temperature and so the hotter the atmosphere, the slower the pressure drops with height.

Now we have a set of equations that essentially allow us to solve a basic atmospheric structure problem. However, there are two things we don’t know. What is T and what is Po? Where does the temperature come from? Well it comes from the balance between the amount of energy that the planet receives from the Sun and the amount it re-radiates into space. The temperature of the planet must be such that it re-radiates as much energy back into space as it receives. The pressure at the base of the atmosphere is related to the atmospheric density through the equation of state. The atmospheric density depends on how much atmospheric material there is in the atmosphere. I’ve kind of implied that it is simple, but in truth it is not that simple. The planet’s temperature depends on the composition of the atmosphere. To solve the problem properly, you need to include the influence of the atmosphere on the incoming and outgoing radiation. This will determine the equilibrium planetary temperature and the variation of temperature with height. You also need to iterate until the density structure gives the correct total mass. However, what determines the pressure profile in the atmosphere is the temperature of the atmosphere and the amount of material in the atmosphere (i.e., the density). The pressure does not determine the temperature. If there was no incoming energy, the atmosphere would lose energy, the temperature would drop, the scale height would decrease and the atmosphere would collapse onto the surface of the planet. When it was cold enough, the molecules would become liquids or solids and the atmosphere would disappear. In other words to have a steady atmospheric pressure, you need incoming energy from the Sun. To re-iterate, the temperature determines the pressure, the pressure does not determine the temperature.

So the reason Venus has a high surface temperature is not because of the high pressure. The reason it has a high pressure is because of the high temperature and density. We can illustrate this by considering the Earth. Atmospheric pressure at sea level is 105 Pa. Atmospheric density at sea level is about 1.2 kg m-3. The atmosphere is primarily nitrogen so μ = 28, mH = 1.67 x 10-27 kg, and k = 1.38 x 10-23 m2 kg s-2. If I plug these numbers into the equation of state shown at the beginning of the post I get T = 338 K. So, the Earth’s temperature is because of our atmospheric pressure, not because of the energy we receive from the Sun! No, clearly this is wrong. If the temperature and density determine the pressure, I can then use the density and pressure to calculate the temperature. It doesn’t mean that the pressure determines the temperature, it just means there’s a relationship between pressure, density and temperature.

Given that I’ve linked to the post on the Watts up with that website, this would normally appear as a comment. I’ll be interested to see if it does indeed appear as such. It’s clear that claiming that the high surface temperature on Venus is due to its high pressure is wrong. Anyone who understands physics would accept this and the author of the post claiming this should recognise this and be willing to acknowledge their mistake. I would have much more time for those who are skeptical of man-made climate change if they were willing to accept when they are wrong. That is essentially the scientific process. Mis-using a set of equations to make a spurious claim is not.