FAIL Better

Recently AT reminded us of FLICC, a taxonomy of contrarian tactics introduced in 2007 by MarkH. His bro’s Deck still shines. As a first post of a science blog, it does the job. As a permanent classifier, it deserves some love. I propose my own model – FAIL. First, some light criticism. Mark lists these items: conspiracy, selectivity (cherry-picking), fake experts, impossible expectations (also known as moving goalposts), and general fallacies of logic. Conspiracy does not resemble a tactic. Moving the goalposts doesn’t imply an unrealistic demand, it only switches criteria in a line of argument {1}. Finally, the last rubric could comprise others. Thus it needs specificity and homogeneity.

That can be accomplished by organizing the tactics along strategies, or as Mark himself observes, as means to frustrate legitimate discussion. How to break exchanges? A classic answer stipulates that communication relies on cooperation. Accordingly, four principles guide our contributions: we try to make them informative, truthful, relevant, and perspicuous. Generalizing or rebranding, we get FAIL:

How to FAIL at Climateball
(Click on the image to zoom in)

In this model, an exchange FAILs when factuality, authenticity, importance or lucidity breaks down. All well and good, now comes the fun part – sorting tactics. To that end I cataloged tricks and determined how they succeed in FAILing. See the tree diagram above. Three characteristics underlie each principle. Connected to them, leaves (the white bubbles) exemplify frustrating tricks {2}. Most terms are commonplace. Before explaining the others, let’s put the model into words:

A contribution is factual with true support, a reality-based conclusion, and under reliable judgment. It is authentic if its author is truthful, committed to the position advanced, and habilitated to propound it. It has import if it addresses the question being discussed, implies a functional call to action, and abides by social conventions. It is lucid if the position is correctly specified (think WYSIWYG), to the point, and not self-defeating. This interprets the cooperative part, shown in colored bubbles. The leaves illustrate obstructive tactics. I offer pairs not for completeness but for contrast. Let’s explain the first row.

Mind probes are as easy to presume as hard to verify; the target of tilting at windmills fails to exist or apply; two sorts of unsoundness. Card stacking is one-sided, the BS Artist says stuff: two clashing ways to lack authenticity. The Peddler exploits cues to hook a recurrent pet topic whatever the exchange, whereas squirreling is the art of deflecting in any other direction than the actual topic. Parsomatics refers to overanalysing words so much that nothing of what is said makes sense anymore; the Soapboxer epilogues and sloganeers with vague platitudes. Two conflicting tactics that drown the exchange in gibberish.

You surely know about armwaving, punting, backpedaling, astroturf, charlatanism, double binds, playing the ref, galloping, soapboxing, racehorsing, and moving the goalposts. Incredibilism has been covered years ago at MT’s, peddling here at AT’s, and Eli introduced parsomatics in his aptly named Law Blogging. Four neologisms beg for a short description. Super Leap denotes any inferential overextension (H/T AlbertC). Void Operation does the exact opposite: nil, with self-sealing, circular or question-begging arguments. Infinite Replays echoes endless quests for Climateball perfection, seldom worth it. Fist Pumping represents excessive celebration, like in SpeedoScience.

Labels and examples ought to help develop a feel for the game. They do not caution to play Fallacy Man: it often bends acceptability {3}. They rather show how to spot what breaks. An unsound argument fails because it lacks support. Astroturfing fails because it fakes support. A double bind fails because nothing can satisfy the support requested. A double standard fails to support anything consistently.

Climateball players do not need any model to understand this. You already know the drill: say what you mean, mean what you say, keep on topic, and try not to hog the mic. Cool kids express their critical skills by meming the eternal questions: (1) u sure, (2) who dis, (3) why tho, and (4) wut. So you got no excuse. Nevertheless, the exercise allowed me to get a better grasp of the tactics for my Manual.

Ever tried. Ever failed. No matter. Try again. FAIL again. FAIL better.

Notes

{1} An expectation can be unreasonable without being impossible to meet it. There are many other dimensions to consider: cost, time, overkill, etc. A point-refuted-a-thousand-times comes to mind.

{2} There is an infinity of rhetorical tricks and more ways to classify them. To capture each one in an exhaustive list would be a fool’s errand. I contend that each breaks at least one of the four axes of FAIL.

{3} Fallacy Man fails to realize that his stance falls to the fallacy fallacy. In fairness, the fallacy fallacy succumbs to the fallacy fallacy fallacy, in turn countered by the fallacy fallacy fallacy fallacy. In short: don’t be the Fallacy Guy.

{4} Here is a simple recipe to recognize a trick. Ask yourself: how does it hinder the ball from moving forward? In a way, armchair contrarians know how to run out the clock.

Posted in ClimateBall, how-to, Pseudoscience, SpeedoScience | Tagged , , , , , , | 10 Comments

Revisiting causality using stochastics

The Proceedings of the Royal Society A has just published two papers by Koutsoyiannis et al. on revisiting causality using stochatics, the first being the theory paper and the second presenting some case studies. One of the case studies in the second paper considered Atmospheric temperature and carbon dioxide concentration, with their results suggesting that

the results in figure 14 suggest a (mono-directional) potentially causal system with T as the cause and [CO2] as the effect.

They then concluded that

[h]ence, the common perception that increasing [CO2] causes increased T can be excluded as it violates the necessary condition for this causality direction

As regular readers will probably realise, this is clearly nonsense. There is overwhelming evidence that the increase in atmospheric CO2 is due to human-caused CO2 emissions, and that this increase is the dominant cause of the increase in global surface temperatures.

There probably isn’t much point in going through all the reasons why what is suggested in this paper is almost certainly wrong. I thought I might simply highlight that I started a PubPeer thread about this paper and Gavin Cawley has already posted a couple of useful comments. A PubPeer thread about the Zharkova et al. paper produced quite an extensive comment thread and probably played a role in it being retracted.

You might argue that a paper shouldn’t be retracted just because one of the case studies produces results that are almost certainly wrong. On the other hand, you might also argue that if one of their case studies produces such results that it rather undermines their whole method. You might also argue that it’s rather embarassing that one of the Royal Society’s journals could publish a paper with what is, these days, a very obviously wrong result.

Posted in Greenhouse effect, Research, Science | Tagged , , | 37 Comments

Limits to Growth?

Tom Murphy, who is a physics professor at UC San Diego, runs a blog called Do the Math. Just over 10 years ago, he had a popular blog post asking can economic growth can last?, which I discussed in one of my a blog posts. A couple of days ago, he published his main arguments in a Nature Physics comment titled Limits to Growth, the full text of which you can also access here.

He makes two main arguments. One relates to waste heat, and the other to physical resource limits. When we utilise energy on the Earth’s surface it eventually turns into waste heat that needs to be radiated into space. At the moment this is negligible. However, if energy usage grows at 2.3% per year, it will increase by an order of magnitude every century and this waste heat would become significant within a few centuries. His argument isn’t that this is likely to happen. It is simply an illustration of a real limit. Admittedly, as pointed out on Twitter, he also doesn’t really make clear that this only applies to non-renewable sources of energy, but there are also limits to how much renewable energy we could use.

His other argument relates to physical resources. There must be some limit to our use of physical resources. This doesn’t necessarily limit economic growth because not all economic activity relies on the usage of physical resources. You could imagine a scenario where we reach a stage where economic growth decouples from the use of physical resources. In other words, we reach the limit of physical resources, the usage of which is now fixed, but economic growth continues through activities that don’t utilise these resources.

The problem that Tom Murphy highlights is that this means that economic activity associated with these physical resources will become an ever decreasing fraction of total economic activity. However, these would be activities that are crucial to our survival, such as food and energy. He suggests that this would be ludicrous. For example, if they become effectively free, how do you stop someone from buying it all and raising the price?

What I would be very interested to hear are mainstream rebuttals to the above argument. It could be that mainstream economics just doesn’t consider century long timescales. If so, does that imply that Tom Murphy’s arguments have validity over these longer timescales? Another could be, as the paper suggests, that the finite physical resources will always be associated with a non-negligible fraction of total economic activity. Hence, they essentially act to limit how much overall economic growth is possible. Alternatively, maybe there are ways to have continued economic growth even if those sectors associated with physical resources become a vanishingly small part of the global economy.

Alternatively, if no mainstream economics are willing to discuss the arguments in Tom Murphy’s paper, maybe my commenters can let me know what they think 🙂

Posted in economics, GRRRRROWTH, Philosophy for Bloggers, physicists, Scientists | Tagged , , , | 198 Comments

FLICC

I should probably be writing about the UK recording temperatures above 40oC for the first time, but it’s been covered pretty extensively elsewhere. Instead I thought I might briefly mention something that I’ve become more interested in and have been thinking about quite a lot recently. Even though I think science communication is important, I also think it’s becoming much more important to identify, and potentially counter, the spread of misinformation, or disinformation.

In that vein, I thought I would promote Skeptical Science’s FLICC taxonomy. These are techniques of science denial, and the acronym stands for Fake experts, Logical fallacies, Impossible expectations, Cherry-picking, and Conspiracy theories. I suspect many who have followed the climate debate can identify examples of each of these techniques.

For example, promoting the credentials of contrarians even though they don’t really have relevant expertise (F). Claiming that climate change today must be natural because it’s changed before (L). Demanding unrealistic levels of certainty before taking any action (I). Selecting a very short period of a dataset that appears to support your arguments, while ignoring all the data that doesn’t (C). Suggesting that climate scientists are somehow incentivised to promote alarming possibilities (C).

There are, of course, many other examples, and each technique can also be considered in more detail, as illustrated by the figure below. I do think it’s worth being more aware of this and trying to work out how to identify when someone, or a group, is promoting misinformation. I would add that it’s probably worth being careful of assuming something is misinformation just because it appears to satisfy one of the techniques highlighted below. It’s probably better to consider if there is a pattern of spreading misinformation, rather than being too quick to judge on the basis of what might be an individual example.

Posted in Climate change, Philosophy for Bloggers | Tagged , , , , | 153 Comments

A bit of a holiday

Lindisfarne castle

You may have noticed that it’s been a little quiet here lately. That’s partly because I’ve had little to say, but also because I’ve been away on holiday with the family. We rented a cottage and spent a week on the Holy Island of Lindisfarne. In case you don’t know, it’s a island off the coast of Northumberland which you access via a causeyway that you can only cross when the tide is low enough.

There’s not a great deal to do on the island, but there is a castle (picture on right) an old priory, a few pubs and cafes, and some really nice walks. You can also cross to the mainland along the Pilgrim’s Way, which is marked by poles and is also only accessible when the tide is low enough.

What was nice was that it would be very quiet either before people could cross the causeyway, or after they had left in order to avoid being trapped for the next four to five hours. I’d mostly use these times to go for a cycle without having to dodge all the other visitors. There was a headland where you could sit and watch the sea birds, look out for dolphins (which I did see on one of the days) and even watch the lifeboat crews try to free a yacht that had managed to get some rope wrapped around its rudder when it sailed over some buoys that were marking lobster pots.

I was also going to comment about the state of the discourse which, as usual, I find somewhat disappointing. However, I’ve probably written enough, so may expand on this at a later stage. I’ll just highlight a tweet from Mark McCaughrean that mostly illustrates the issue that I have. Essentially, I find it difficult to know who to trust when it comes to topics I’m not that familiar with, such as how to implement climate policy, or what is realistic when it comes to energy policy.

It almost feels that everyone is engaging in rhetoric styles that are more aimed at appealing to certain audiences than in providing reliable information about complex issues. Maybe this is simply unavoidable, but I do find that it makes it difficult to sift through things to try and work out what to trust and what to be more dubious about. Maybe this is unavoidable, but I do find it frustrating at times.

Posted in Personal, Philosophy for Bloggers, Policy | Tagged , , | 27 Comments

Climate change and social justice

The Institute for Strategic Dialogue (ISD) recently released a called Deny, Deceive, Delay: Documenting and responding to climate disinformation at COP26 and beyond. It highlighted a number of people who will be familiar to those who have followed the public climate debate, and used a taxonomy for Discourses of delay presented by Lamb et al. These discourses of delay are various narratives that can be used to argue against and, hence, delay effective cimate action.

There are a number of different climate delaying discourses, but one of them is an appeal to social justice. Essentially, arguing that climate action will have large costs that will pre-dominantly impact the most vulnerable. As highighted in the ISD report, this has led to environmentalism becoming a new front in the culture wars.

This issue is something I have pondered from time to time, but have never quite seemed to express my thoughts as clearly as maybe I should. I also worry that maybe it’s a form of just asking questions, so will acknowledge this in advance. I should also acknowledge that this falls well outside my area of expertise, so some of my terminology may be, un-intentionally, not ideal.

It seems clear that there are social justice issues associated with climate change. Some groups will be more severely impacted than others, and it seems likely that those who’ve contributed least will suffer most. So, it seems that if we want to develop climate policy that is fair, then these kind of social justice issues should be taken into account.

However, the more we focus on these kind of issues, the more we would seem to run the risk of falling into the culture wars and, potentially, validating what are probably disingenuous social justice arguments. For example, those (such as Alex Epstein) who seem to argue that we should expand the use of fossil fuels so as to deal with some of these issues. On the other hand, there probably are perfectly valid arguments for expanded fossil fuel use in some circumstances. Also, I certainly don’t think that those of us who have benefitted from the use of fossil fuels should be telling those who haven’t what they should do.

I’m not sure if I’ve expressed my concern all that clearly. I’m certainly not arguing against highlighting the importance of social justice when thinking about how to deal with climate change. Mostly I’m wondering how you do so without it ending up being counter-productive. Maybe one option is to highlight discourses of delay and identify who is spreading disinformation, and how they’re doing so. Maybe we just should just make the strongest arguments we can and shouldn’t really care about bad-faith actors. On the other hand, being aware can at least help to identify easily avoidable pitfalls.

I should probably stop there, as I’m not really sure what else to say. I’m actually on the train down to Cambridge for a few days, so am going to get out my book and relax for a while. However, if anyone does have any thoughts on this, I would be interested to hear them.

Posted in Climate change, Philosophy for Bloggers, Policy | Tagged , , , | 93 Comments

The ‘hot model’ problem

Zeke Hausfather and colleagues recently wrote a Nature comment with suggestions about how to deal with what is called the ‘hot model’ problem. The issue is that some of the latest group of climate models have somewhat higher than expected climate sensitivities. To account for this, in the latest IPCC report the models were weighted to give more weight to those that better represented historical temperature observations.

This weighting reduced the range of projected warming for the various scenarios and reduced the likely climate sensitivity ranges. Additionally, in previous IPCC reports what has often been presented is what will happen in 2100 along different possible emission scenarios. However, if there are some potentially anomalous “hot models”, then the range of warming in 2100 for each scenario would be quite broad and the possible 2100 climate could vary quite widely for a given scenario.

To account for this, what the recent IPCC report did was to use Global Warming Levels (GWLs) rather than presenting the output at 2100 for each set of scenarios. In other words, rather than reporting how the climate will change in 2100 for each scenario set, they highlighted the changes that will probably occur if we were to warm by 1.5oC, 2oC, 3oC and 4oC. The advantage of this is that you can use all the models and may not need to weight them; even a “hot model” may give a reasonable representation of the climate in a, for example, 2oC world, even if it gets there sooner and for a lower level of cumulative emissions.

However a lot of the current research that assesses the impact of climate change still use the scenarios, rather than using GWLs, and doesn’t account for the possibility that some models are “too hot”. The Hausfather et al. article was basically suggesting that researchers who use climate model output to assess the impact of climate change should aim to follow a similar practice to what was presented in the most recent IPCC report. Use GWLs, rather than simply focussing on scenarios going to 2100, weight the models if the warming trajectory is relevant, and try to consider which models may be best suited to the problem that is being considered.

The reason I thought I would write about this is partly that it’s interesting and I haven’t had much to write about recently, and partly because Mike Hulme wrote a critical response. In the original article, the authors claim that “despite some differences related to the rate of warming and aerosol forcing, the world largely looks the same at 2 °C, no matter how we get there.” Mike Hulme’s response suggests that “[a]gainst criteria that matter, not all future 2 °C worlds would be the same — even though the climate might be.

Of course, Mike Hulme is correct that there isn’t a single 2oC world. It will depend on the various socio-economic factors that Mike Hulme mentions in his response. However, I’m pretty sure that the authors of the article were not implying otherwise, even if it is unfortunate that they chose to say “the world looks largely the same“. Given that the context was the output from climate models, I’m pretty sure that what they meant was that the world’s climate will look largely the same, which even Mike Hulme acknowledges in his response.

I find this kind of thing rather frustrating, especially as the original article was addressing a problem and making constructive suggestions about how to use climate model outputs to assess the impact of climate change. The point of the article was not to convince people that the future world will depend only on the level of global warming. The article was presenting a set of suggestions for how those who assess what the world might look like should use the output from climate models. In a sense, the article was trying to help researchers do the very thing that Mike Hulme’s criticism seems to imply that the authors don’t understand.

Posted in Climate change, Gavin Schmidt, Global warming, Research, The philosophy of science | Tagged , , , , | 207 Comments

World Atmospheric CO2

Early this year, a journal called Health Physics published a paper on World Atmospheric CO2, Its 14C Specific Activity, Non-fossil Component, Anthropogenic Fossil Component, and Emissions (1750–2018). The paper concluded that

Our results show that the percentage of the total CO2 due to the use of fossil fuels from 1750 to 2018 increased from 0% in 1750 to 12% in 2018, much too low to be the cause of global warming.

As you can imagine, this gained some traction amongst those who dispute that anthropogenic emissions drive global warming.

In the June edition of the journal there were 4 letters criticising the article, the authors of which included Pieter Tans, Ralph Keeling and Stephen Schwartz. The July edition then included a letter from myself, Gunnar Schade and Mark Maslin.

The letters point out that the paper’s assumptions about 14CO2 are inconsistent with observations, that it ignores the impact of the bomb tests in the 1950s and 1960s, and ignores that there are large exchange fluxes between the atmosphere, ocean, and terrestrial biosphere. It’s very obvious that the increase in atmospheric CO2 since the mid-1700s is almost entirely due to anthropogenic emissions and it’s rather surprising that a bunch of physicists don’t get that if you want to consider the detailed evolution of atmospheric CO2 concentrations, you really do need to consider all of the fluxes.

The authors of the original paper, of course, think that the criticisms don’t actually address their assumptions, methodology, or results, and they stand by [their] methodology, results and conclusions. Somewhat bizarrely, the authors still seem to think that the increase in atmospheric CO2 can only be anthropogenic if all of the CO2 that makes up this increase has a direct anthropogenic origin, rather than (obviously) the increase would not have happened in the absence of anthropogenic emissions.

The editor of the journal has also responded to say that they stand by their decision to publish the paper and invited readers to examine the original paper, the criticisms in the Letters in this issue, and the authors’ responses to these criticisms and come to their own informed conclusions of this work. This is all good and well, but understanding why the rise in atmospheric CO2 is almost entirely anthropogenic is pretty straightforward, it’s been well established in the relevant field for a very long time, and the only people who dispute this are justifiably described (in my view) as science deniers.

I don’t expect the letters to really change the minds of those who still dispute that the increase in atmospheric CO2 is almost entirely due to anthropogenic emissions, but I do think it’s useful for them to have been published. They at least provide something to highlight when people promote the original paper. Since ours isn’t fully public, if you’re interested in reading it, you can download the accepted version here.

Update:

I should have acknowledged that there were some who provided useful comments on drafts of the letter. So, thanks to Dikran, Bob L. and A.N. Other for their comments that helped to improve what we submitted.

Posted in Climate change, physicists, Research, The scientific method | Tagged , , , , , , | 105 Comments

The science-society interface

I came across an interesting paper by Dietram Scheufele on Thirty Years of science-society interfaces: What’s next, which focusses mostly on science communication. Although – as the article mentions – this isn’t the only possible science-society interface. Since I have an interest in this myself, I thought I might add some reflections of my own, but from the perspective of a scientist who is trying to communicate, rather than from the perspective of a scholar who studies the science-society interface.

In my experience there are, broadly speaking, two groups of scholars who focus on science communication. There are those who are actively trying to find ways to help scientists communicate more effectively. For example, the group at George Mason University, which included John Cook from Skeptical Science, with whom I’ve done some work. John has since moved to the Climate Change Communication Research hub at Monash University.

The other group are those who seem to regard their role as analysing the interface between science and society, critiquing how scientists engage publicly, and – in some sense – almost defining the appropriate manner in which scientists should interact with the broader public. The author of the above paper seems to belong more to this group, than to the former group.

Unfortunately, my interaction with the latter group of scholars has often been less than positive, which may of course reflect more on me than on them. However, I sometimes find the premise of their scholarship a little arrogant, as if they’re in some special position where they get to critique other scholars without seeming to recognise an equivalence between themselves and those they’re choosing to critique. There can also be a tendency to generalise about scientists, and to be rather dismissive of feedback coming from scientists. There are also some who have, in my view, actively hampered attempts to communicate science.

There can also be an element of irony in what is often presented by these scholars and this is somewhat evident in the article mentioned above. A common claim is that scientists who engage publicly suffer from what is referred to as deficit model thinking. The basic idea is that scientists think that science communication acts to fill some knowledge deficit which then leads to the public understanding the basic issue and accepting the policies that might derive from the scientific information. Of course, this is not how things work in reality. It is clearly much more complex, and there are many factors that infuence whether or not someone will accept a scientific position and what they would be willing to do even if they did.

However, it often seems that the scholars who criticise scientists for deficit model thinking end up doing something very similar themselves. They will imply that their field has developed a deep understanding of the science-society interface, that this is not being considered by scientists who engage publicly, and that if scientists did pay more attention to it, the interaction between scientists and society would be greatly improved. It may not be exactly deficit model thinking, but it seems pretty close. It’s almost as if these scholars don’t quite believe what their own scholarship seems to imply.

I also wanted to add something else about deficit model thinking. I’m a scientist who has spent quite a lot of time engaging in various forms of science communication. The reason I focus on trying to explain the “science” is that I enjoy doing so, I feel comfortable doing so, and because it allows me to focus on topics in which I think I have some relevant expertise. I’m not doing it because I think that all that needs to happen in order to solve various complex socio-political issues is for people to understand, and accept, the scientific information that I’m choosing to present. I’m well aware that it’s more more complex than that. I sometimes wonder if those who criticise scientists for deficit model thinking have really considered this from the perspective of those scientists who are choosing to engage publicly.

Okay, this is getting rather long, so I should wrap up. I do think that these are important issues and I do think that it is a topic that scholars should interrogate. However, if those who do so are essentially suggesting that scientists at the science-society interface should reflect on how they engage, then there may be merit in them doing some reflection themselves. To be fair, the article above does include some reflection, which is good to see. However, as I suspect such scholars would acknowledge, if your audience isn’t accepting your message, then maybe this indicates some issue with what you’re presenting, or how you’re doing so, rather than an indication that the audience is ignoring an obvious “truth”.

Posted in Climate change, Philosophy for Bloggers, Scientists, The philosophy of science, Uncategorized | Tagged , , , | 120 Comments

The Greenhouse Effect

I’ve ended up in a rather silly discussion/debate on Twitter about the Greenhouse Effect. I realise it’s rather pointless, in that those who dispute it are very unlikely to accept its reality. However, it’s still interesting to think about how to construct an argument, and it gave me an opportunity to highlight some papers and articles that might be of interest to others. I thought I might repeat some of it here.

One of the arguments being made is that noone has demonstrated that CO2 can provide the backradiation that heats the surface. Firstly, it’s not simply CO2, it’s emission back to the surface from the lower atmosphere. Also, given an average surface temperature of around 288K, we know the surface must be radiating almost 400 Wm2. It also loses just over 100 Wm2 through evapo-transpiration and thermals (see energy balance figure on the right).

However, the surface receives less than 200 Wm2 from the Sun. Hence, to be in energy balance, there must be an additional energy flux, with a magnitude of over 300 Wm2. This is the back-radiation from the lower atmosphere. If it wasn’t there, the surface would be losing much more energy than it was receiving and would rapidly cool. This clearly is not happening, hence there must be some backradiation. I should add, that it has also been measured.

Another argument is that the effect of CO2 is now saturated. This is an old argument that has been addressed a good number of years ago. It illustrates a rather fundamental misunderstanding of the Greenhouse effect. What’s not always well understood is that convection in the lower atmosphere (troposphere) is important. Convection plays a role in the atmospheric temperature decreasing with increasing altitude; it gets colder as you go up in the atmosphere.

The presence of greenhouse gases in the atmosphere prevents all of the energy from being radiated to space directly from the surface. Instead some of the energy is radiated to space from within the atmosphere. Since the system will tend to energy balance, and since temperature decreases as you go to higher altitudes, this means that the surface has to be warmer than it would be in the absence of an atmosphere; the Greenhouse effect.

Credit: Rasmus Benestad, Realclimate

Also, as illustrated very nicely in the Figure on the right, taken from this Realclimate post, adding more greenhouse gases to the atmosphere increases the altitude at which energy is radiated to space. Again, since the temperature decreases with altitude, this would then require that the lower atmosphere and surface would have to warm to return the system to energy balance; the enhanced Greenhouse effect. This is what we’re doing now with our emissions of CO2, and other greenhouse gases.

A final claim is that most of our recent warming is due to increases in absorbed solar radiation, which contradicts what’s expected from the Greenhouse effect. This is a somewhat subtler point but, again, illustrates a misunderstanding of how the Greenhouse effect actually works.

A somewhat simplistic view of the Greenhouse effect is that adding greenhouse gases to the atmosphere reduces the outgoing longwave flux, which then recovers as the system warms back to equilibrium. However, as I explain in this post, there are both short- and long-wavelength feedbacks. The outgoing longwave flux actually recovers quite quickly. However, the shortwave feedback (mostly due to changes in clouds) leads to an increase in absorbed solar radiation, which causes the system to keep warming, increasing the outgoing longwave flux to above the level it had before the greenhouse gas concentrations increased.

So, in a sense, this continued warming is due to an increase in absorbed solar radiation, but this doesn’t mean that this wasn’t caused by the initial increase in greenhouse gases in the atmosphere. It doesn’t somehow contradict what we expect from the Greenhouse effect.

Anyway, I think it’s useful to think about these things even if arguing about it on Twitter is mostly pointless. A key point, which I’ve probably highlighted before, is that if someone thinks they’ve encountered some simple, and obvious, reason why a well accepted scientific argument is flawed, maybe they should first check that they properly understand the scientific argument they claim to have overthrown.

Posted in Climate change, Global warming, Greenhouse effect, Science | Tagged , , , , | 214 Comments