Hurricanes and carbon cuts

I was wanting to quickly comment on a recent Bjorn Lomborg article in the New York Post called No, global warming isn’t causing worse hurricanes. It’s mainly a response to another article in the New York Post called Climate change is making hurricanes way more intense.

There are a number of issues with Bjorn Lomborg’s article. It is true that we might expect anthropogenically-driven global warming to lead to fewer hurricanes overall, but we still expect an increase in the frequency and intensity of the strongest ones. There is already an indication of an increase in the frequency and intensity of the strongest storms in the North Atlantic, which appears to be linked to increased sea surface temperatures.

However, the bit of the article that I found most disingenuous was when it discusses

why carbon cuts are a terrible way to reduce hurricane damage.

Anyone whose been involved in this topic for as long as Bjorn Lomborg has must realise that carbon cuts are not simply aimed at reducing hurricane damage. Our emission of CO₂ into the atmosphere is changing our climate, which has many different impacts. There’s warming of the troposphere, which will likely lead to increase in the frequency and intensity of heatwaves. There’s likely to be an increase in the frequency and intensity of extreme precipitation events. There’s sea level rise, which could have a significant impact on many coastal communities. There will be an expansion of the tropics, substantially changing the climate in some regions. There will probably also be an increase in the frequency and intensity of some extreme weather events. These changes will also probably impact droughts and flooding.

So, yes, if all had to worry about was damage due to hurricanes, carbon cuts might well be a poor way to deal with this. However, this clearly is not the only thing we will have to face, and so carbon cuts are not simply meant to address increased damage due to hurricanes. It is probably true that some use hurricanes to highlight some of the risks we might face and to motivate climate action. However, clearly most are not suggesting that the only risk we face in future is increased damages to more extreme hurricanes.

Maybe we should be careful of using things like hurricanes to motivate carbon cuts, since this does ignore many other reasons for doing so. However, you can understand why this happens. Hurricanes can be very impactful events and can draw a lot of public attention. The main problem is probably that doing so then allows bad faith actors to make disingenuous arguments against carbon cuts. I’m not sure, however, that there’s really all that much that we can do to avoid this.

Links:
Climate Science Special Report (2017) – which says Human activities have contributed substantially to observed ocean–atmosphere variability in the Atlantic Ocean (medium confidence), and these changes have contributed to the observed upward trend in North Atlantic hurricane activity since the 1970s (medium confidence).
Intensification of landfalling typhoons over the northwest Pacific since the late 1970s – which says typhoons that strike East and Southeast Asia have intensified by 12–15%, with the proportion of storms of categories 4 and 5 having doubled or even tripled. ….. We find that the increased intensity of landfalling typhoons is due to strengthened intensification rates, which in turn are tied to locally enhanced ocean surface warming on the rim of East and Southeast Asia. (H/T David Appell).

Advertisements

The time evolution of climate sensitivity

I wanted to just post this figure from a new paper by Philip Goodwin called On the time evolution of climate sensitivity and future warming. It uses a modified energy balance approach in which multiple climate feedbacks evolve independently over time to multiple sources of radiative forcing. As many other studies have shown, the ECS you infer depends on the timescale considered. It suggests that if you consider decadal timescales, the ECS will be biased low, and that on century timescales, the ECS has a likely (66%) range that goes from just above 2K to around 3.5K, with a best estimate of about 3K.

Credit: Goodwin (2018)

We Are Science

After a few days of presentations on (gasp!) science communication, a party was being held in Iceland. Many dignitaries, a few allocutions, among them one by a lady from the banking industry, more exactly a PR big boss from a Canadian bank. (When you hear “Canadian bank,” think serious business.) To this day one of her points stuck with me.

After thanking everyone for their enlightening talks, she said something like this. “You know what attracted me first when I entered this beautiful room? The photos on the piano. Images of people. I like to see people. People like people. It’s you that fascinates me, what you say comes after.”

A story connects characters with events, persons and deeds, agents and topics. A good science piece, to me, is one that allows me to see a scientist in action, trying to solve a mystery, sharing a passion for the object of study, showing what is done, and how. The why or the wherefore comes after.

Equations, data, code, never stand alone. If you want to sell me a theory, first tell me a story in a way I can hear an authentic voice and see the glimmer in your eyes. That last part could be a metaphor, but when “going public,” consider making it as real as possible. Image and presence matter. I’ve heard of conferences offering professional shooting sessions. Performances require preparation. Actors still need directors.

Imagine a scientist in your head. Your image may differ from the silly scientist stereotype. Or not – even scientists entertain it. We got a political problem on our hands, and we want to bring about a set of science based solutions. To paraphrase Wilfrid, the scientists’ image needs to change.

***

This first big step isn’t enough. In an exemplary abstract, Gabriel Lenz argues that scientific practices need to change too:

Political scientists should put aside questions about whether voters are rational or irrational, informed or uninformed, and questions about how flawed democracy is. Although they are interesting, these questions are secondary. Answering them in no way helps people—it does not help them with their violent neighborhoods, their declining incomes, their flooded homes, or their dying crops. Instead, researchers should focus on the first-order question of how to improve democratic accountability.

One radical way to improve democratic accountability and help people would be for scientists to run for office. But change can take tinier steps. Angela Potochnik recalls for instance that scientific practices are shaped not just by the need for the scientific enterprise to connect with the world, but also by the need for the scientific enterprise to connect with its human practitioners and audience. Verena Halsmayer argues that we should be following artifacts in the creation of economic theories. The following suggestion would compel theoricians to concretize their insights:

I would love to see a professional conference that, instead of having a bunch of academics presenting to each other in hotel ballrooms, actually turned academics loose in the host city to present TO THE PUBLIC. Bring some free education to the host city! Leave the hotel!

— Bex (@rjgstone) September 5, 2018

What I’m suggesting may not cohere with current academic practices. I could not care less.  Academics waste too much energy on stuff nobody reads. We’re past satisfying ourselves with communicatin’  – if what you’re saying doesn’t call for any action, why say it?

Let’s try to cut the empty talk and try to rock the world with our words. It’s OK to be angry, as long as it leads somewhere constructive. It’s OK to be stressed by our predicament. It’s OK to be an advocate too:

> [C]limate scientists who wish to engage in certain forms of advocacy have considerable latitude to do so without risking harm to their credibility, or the credibility of the scientific community.

There is only one time that matters for change – immediately, as Krishnamurti said time and time again. All one needs is to put one foot in front of the other. Collective action can’t wait until all agree on everything. Religion won’t go way and conservatism won’t disappear soon. Disagreeing should make us stronger.

Humanity is the only way out for those stuck in an echo chamber. Eric Holtaus is naming every identified victim of Porto Rico as we speak. Childish Gambino sings the happenstance of Anthropogenic Global Warming (AGW) because he can:

I have no recipe to offer. Anything goes as long as we all agree on the following. The ideals of Open Science entail sharing everything with everyone. We need to show it to people because we’re all in it together, and because it rocks the world. We need to start doing things with our words. We need to accept everyone willing to fight with us, otherwise we will suffer the consequences.

Hence why we are Science.

Disasters and Climate Change – part 2

Since I have a bit of free time, I thought I would expand a little on my Review of Roger Pielke Jr’s book about Disasters and Climate Change. As I mentioned in my earlier post, there were a number of things I disagree with, so thought I would expand a little on those here.

One thing that should be stressed is that what the book was mostly highlighting is that there is no indication that trends in disaster losses are due to human-caused climate change. This does not mean that we have not been able to attribute changes in some extreme events to human-caused climate change, because we have; the book is focusing on trends in disasters, not trends in the extreme events themselves.

Of course, that we may not be able to detect a trend in disaster losses that is due to human-caused climate change, does not mean that there is no such trend. However, the book argues that a signal that may exist, but which cannot be detected, is indistinguishable from a signal that does not exist. The book points out that God, aliens, and celestial teapots are also examples of things for which we have no evidence, but that we might want to believe do exist.

The problem, though, is that climate change is clearly happening and is predominantly being driven by our emission of greenhouse gases into the atmosphere. It’s already changing the conditions associated with extreme events and, in some cases, we’ve even detected a climate change related influence in some of these events. It may well be that other factors are dominating trends in disaster losses, but it would be remarkable if climate change was having no impact at all. I don’t think that this means that we should assume that human-caused climate change has contributed to some of the trend in disaster losses, but does – in my view – mean that we should be cautious of assuming that the lack of a detectable trend means that there is no trend. Even if we can’t detect something now, it seems very likely that we will in the future if we continue to dump CO₂ into the atmosphere.

The other thing I was going to discuss was the argument against single event attribution. The suggestion is that this abandons the IPCC framework, which involves detecting trends over climatologically relevant timescales, and then trying to establish if anthropogenically-driven climate change was a cause of this trend. The IPCC, however, is simply an organisation that produces synthesis reports; it doesn’t – as far as I’m aware – have any mandate to specify appropriate scientific methodology. Also, single event attribution is an entirely reasonable thing to do. You consider the conditions associated with an extreme event, try to determine if these conditions could have been influenced by human-caused climate change and, hence, how this may have influenced the extreme event itself. Arguing against this is essentially arguing against doing physics. Patrick Brown has a nice post that briefly discusses this and presents an illustrative video.

As usual, this post is now too long. I wanted to finish by highlighting an earlier post in which I discuss extreme events and anthropogenic emissions and argue that formal attribution is not really all that relevant; we don’t really need to do some kind of formal attribution study to be quite confident that our emission of greenhouse gases into the atmosphere will probably influence extreme events. Understanding how it will do so, and the likely impact, clearly is important, but that’s somewhat distinct from demonstrating an anthropogenic cause.

Links:
Signal, Noise and Global Warming’s Influence on Weather – post by Patrick Brown.
Extreme events and anthropogenic emissions. – earlier post about attributing anthropogenic emissions to trends in disaster losses.
Economic losses from US hurricanes consistent with an influence from climate change – a paper by Estrada, Wouter Botzen and Tol estimat[ing] that, in 2005, US$2 to US$14 billion of the recorded annual losses could be attributable to climate change, 2 to 12% of that year’s normalized losses.

Disasters and Climate Change

Roger Pielke Jr emailed me an advance copy of the 2nd edition of his book on Disasters and Climate Change. Roger’s email ended with I welcome your reactions, comments, critique. Past experience makes me slightly dubious, but I will take Roger at his word.

I’ve read the book, twice in fact, and am finding it quite hard to know what to say. Even though there are a number of things that I disagree with, I think it mostly presents information that is defensible. However, what I think many will conclude from reading this book is not really consistent with our best understanding of this topic.

Since I’m still recovering from having organised a conference that ran all of last week, I’m going to try and keep this short and just make some general comments. There are some specific issues that I may discuss in a later post.

The book discusses how unpleasant and difficult the public climate change debate can be. I think it definitely can be, but I also think it’s worth reflecting on how one’s style of engagement might have influenced how one’s views were received. There is plenty of discussion on whether or not disasters [have] become costlier because of human-caused climate change. The answer is no, the data don’t support claims that the rising costs of climate disasters are due in any part to a human influence on climate. There is even an argument that we should assume that the lack of a detectable signal should be taken as the signal not existing (I don’t agree with this, but will leave this for another post).

There is also a discussion of detection and attribution, that I may discuss further in another post. The book concludes with a discussion about policy and highlights the Kaya identity (emissions are basically a function of GDP, population, how we get our energy, and how we use our energy). It also highights an iron law. GDP growth is essentially sacrosant; any climate policy that will significantly impact GDP growth will never be accepted. It also discusses how difficult it’s going to be to reduce emissions sufficiently. Interestingly, it seems to mostly argue against a carbon tax (one that would have any significant effect, at least).

As I said at the beginning, there are many things I disagree with, but I think a lot of what is presented is probably broadly correct, or at least defensible. We may not yet have demonstrated that climate change has caused disasters to become more costly, it may indeed be difficult to develop effective policy, and getting emissions to reduce sufficiently is going to be very challenging. My biggest issue with the book is that, despite it containing all the necessary caveats, I think it will be used by those who oppose climate policy to argue that there is no evidence that anthropogenically-driven climate change is having any impact on us and, if it is, doing anything ambitious about this will simply not work. If that is the message that was intended, then it’s worked.

If anything, it’s hard to really interpret the intention in any other way. The final chapter seems to explicitly argue against anything too ambitious. The problem, in my view, is that there are indications that unless we get emissions to reduce soon, the resulting climate change could be severely disruptive. I think the book mostly ignores this possibility and seems to present an argument for a policy pathway that we may well be able to achieve, but that may fail to effectively address anthropogenically-driven climate change. I don’t see this as particularly helpful. Others may, of course, disagree.

Links:

Gavin Cawley has a couple of Twitter threads about the book.

The ECS is probably above 2K

I have quite a large conference starting tomorrow, so will probably be too busy to write. To keep things ticking over I thought I would post this seminar given by Andrew Dessler, discussing his recent work on constraining the Equilibrium Climate Sensitivity (ECS). I’ll note that JCH posted a comment about this yesterday, but I had already seen it.

I’ve written a couple of posts about Andrew’s recent papers, but the seminar explains it all very nicely.

The bottom line is essentially that we have strong reasons to think that the lower bound for ECS is probably above 2K, despite some recent work suggesting that it might be below 2K (i.e., we largely understand why this work gets that result and why it’s probably wrong, in the sense that the ECS is more likely to be above 2K, than below 2K). Essentially, this work suggests that the likely range (17% to 83%) for ECS is about 2.4K to 4.5K, with a median at 3.3K.

Linking climate change and extreme events

There’s an article in the New Republic called the media’s failure to connext the dots on climate change. I actually came across it via a blog post by Matthew Nisbet in which he argues that [Why] The New Republic is wrong to argue for journalists to label every extreme weather event and disaster as linked to climate change. Not only do I think he slightly misrepresents what the New Republic article is suggesting, I also think what they suggest is mostly quite reasonable. I’ll try to explain why.

Climate change is clearly happening and it is mainly driven by our emission of greenhouse gases (mostly CO₂) into the atmosphere. Doing so causes atmospheric CO₂ to increase, reducing the outgoing energy flux and causing energy to accumulate in the climate system. This will lead to warming of the surface and troposphere, increasing ocean heat content (and increasing sea surface temperatues), an increase in evaporation, an increase in the frequency and intensity of extreme precipitation events, and a change in the latitudonal temperature gradient that has the potential to influence the jet stream and, hence, weather patterns. This means that in regions that are susceptible to extreme weather events, the conditions will increasingly tend to favour these events becoming more extreme.

I will admit that we could sometimes be more careful about how we associate climate change and extreme events, and there will almost certainly be situations in which it’s not really appropriate to include some discussion of climate change. However, climate change is clearly changing the environment in which these extreme events are occuring and, in many situations, leading to conditions that make it likely that we will see an increase in both the frequency and intensity of such events.

I think it’s important that this is understood. Even if we cannot definitively attribute a climate change link to a specific event does not mean that we can’t discuss how climate change is likely to impact such events and whether or not we’re seeing changes that are consistent with what is expected. If we want to make ourselves more resilient to such events, then it would seem important to understand how climate change is likely to influence them. Furthermore, until we get net emissions to almost zero, the climate will continue to change and we will likely continue to see an increase in the frequency and intensity of many of these extreme weather events.

To be clear, maybe I misunderstand some of what is being suggested. Also, maybe there are subtle reason why avoiding associating extreme events with climate change will somehow help us to become more resilient to these events. On the other hand, I do find it difficult to understand how avoiding discussing a climate change link will somehow help us to develop policies that effectively address this issue. Maybe I’m just a naive physicist (okay, yes I probably am) but if we do want to think about how to address the risks associated with climate change, then we really should be discussing it openly so as to help the public, and policy makers, better understand how it is likely to impact us, both now and in the future.