Andrew Dessler and Zeke Hausfather have a reasonably new substack called Climate Brink. Andrew’s most recent post on why (are) climate impacts are accelerating so quickly caused some rather heated discussion on Twitter.
You could argue that Andrew could have been a bit less definitive, but I think the basic point he was making was perfectly reasonable. The impacts of climate change are likely to be non-linear. You could even ignore climate change for the moment and just recognise that the impacts of climatic events are likely to be non-linear.
Our societies can generally cope easily with certain events. In fact, there will be events that are sufficiently mild that they have essentially no adverse impact. However, if an event is particularly intense it may overwhelm whatever we have in place to cope with these events and the impact will suddenly become very large. In other words, the impact doesn’t simply depend linearly on the magnitude of the event.
If we now include climate change, then we expect some extreme weather events to become more frequent and/or intense. Hence, there may come a time when these events will more often cross these thresholds where our societies are no longer able to easily cope. If the events also have a tendency to be more intense, they would also have a larger adverse impact. The suggestion in Andrew’s post is that we’re already starting to see this and that this makes sense, given what we might expect.
One of the main criticisms of this framing is that it assumes that our societies won’t adapt so as to reduce the impact of these events and that there is plenty of evidence that we’ve successfully done so in the past. This is certainly a possibility, but it does seem to assume that we’ll be updating our infrastructure at a suitable rate and that all regions will have the resources to do so.
We also have to bear in mind that the climate will continue to change until we get emissions to (net) zero. So, if someone is confident that we won’t see increasing adverse impacts from climate change, they either believe that we’ll successfully adapt to whatever changes might occur, or think we’ll get emissions to (net) zero fast enough that changes in the frequency/intensity of extreme events won’t be sufficient to produce substantially enhanced adverse impacts. Or, some combination of adaptation and emissions reductions will effectively limit the impact of climate change.
There is some merit to being optimistic, but it might also be worth recognising that some are justifiably much less optimistic that we will actually take sufficient action in time to avoid increasingly adverse impacts from climate change. Admittedly, one of those complaining about the framing in the article was Ted Nordaus, who seems to make a habit of promoting alternative framings that sounds distinctly undramatic and rather benign, so maybe I shouldn’t really be all that surprised.
...and Then There's Physics 
Something I don’t quite get about the “don’t worry, we’ll adapt so that the impacts of climate change won’t be increasingly severe” argument is that adapatation isn’t free. Of course, investing in better infrastructure will have benefits, but it will also probably mean not investing in other things that might benefit society. So, even if we could adapt in such a way that the impact of climate change doesn’t become increasingly severe, that doesn’t – I think – mean that there isn’t any possible adverse impact.
BTI = Bad Take Institute ROTFLMFAO 😀
Quibble: Climate will continue to change even after emissions get to net zero, because at that point energy in the global system will not have equilibrated to GHG concentrations.
Tom,
The current understanding is that when emissions get to (net) zero, the natural sinks will continue to take up *some* of what we’ve emitted so that GHG concentrations actually decrease in such a way that warming (roughly) stabilises. There are, of course, uncertainties, so warming could continue for a while, or there could be some cooling. However, the best estimate is that global average surface temperatures will stabilise soon after emissions get to (net) zero. This Carbon Brief article explains it well.
https://www.carbonbrief.org/explainer-will-global-warming-stop-as-soon-as-net-zero-emissions-are-reached/
You noticed my tag. 🙂
You’re right – I conflated zero-net with constant concentration.
I think your last point is key. It’s easy to look at ZECMIP and be optimistic … but even its “gradual” bell-shaped trajectories are pretty stylized and imply very rapid turnover of emitting capital. I’m skeptical that we’ll see that, but it is nice that even slower reduction scenarios may see some fairly immediate relief in the rate of temperature rise, and therefore a slower climb up the nonlinearities.
LOL. “heated debate”. I can’t think of anything I’d less like to do than debate with those bad-faith carnival hucksters on social media. Seriously, what a waste of time.
ATTP: “The current understanding is that when emissions get to (net) zero, the natural sinks will continue to take up *some* of what we’ve emitted so that GHG concentrations actually decrease in such a way that warming (roughly) stabilises.”
That will be at a higher temperature than before, and last a while, so much of the climate will still be oscillating to a new state. Ice sheets and glaciers will keep melting to their new equilibrium, throwing off changes in albedo, sea level, river water supplies, etc. Precipitation, high-water marks, winds and currents will all be changed.
The changes will cause non-linear shifts, but also the ones that nibble away at things that might be linear because they just build fairly steadily to a new normal.
Miami invested half a billion dollars in some infrastructure upgrades, but that makes the city less affordable, and would a tipping point there be when there’s suddenly a six-times bigger tax hike to raise the entire sewage treatment system, or when it becomes too hard for service workers to live in the area?
Big events get headlines, especially when many people are then on the move, but there’s also the slower buildup of aggravation, dwindling property values and a less-enjoyable life.
In the US South, summer heat might be an example of that driver. People retiring somewhere for the nice winters might realize the new normal summer is way too hot. People loving the mountain West might avoid wildfires, but be driven back away by the cost of a water supply for their new home.
Maybe the future climate forecast is “linearly-increasing annoyance, with chance of major non-linear events”. Both will affect people’s decisions.
Andrew,
Indeed, but I still do have moments of naivety when I think it might be worth engaging. It rarely is and these moments are much rarer than they used to be.
b fagan,
You’re quite right of course that global average temperatures might stabilise soon after emissions get to (net) zero, but these enhanced temperatures will not reverse for a very long time. Consequently, there will be some things (sea level rise) will still continue to change for a long time. Hence, some impacts may get more severe even after emissions get to (net) zero.
Tom,
Indeed.
You say “We also have to bear in mind that the climate will continue to change until we get emissions to (net) zero. ” Won’t it continue to change for some time afterwards, until CO₂ levels return to pre-industrial levels? When we reach net zero, we are only stopping the increase, not reversing it.
> adapatation isn’t free
Neither is money spent on new energy infrastructure. So, you would need to balance those two costs, rather than assuming one or another.
> there is plenty of evidence that we’ve successfully done so in the past
Indeed; and little evidence that this won’t continue.
Otto,
When human emissions get to (net) zero (i.e., either when we stop all emissions, or use technology to capture and store as much as is being emitted into the atmosphere) we expect the natural sinks to continue taking up *some* of what we’ve emitted. Hence, atmospheric CO2 levels should decrease in such a way that global average surface temperatures should soon stabilise (i.e., stop increasing). However, the decrease in atmospheric CO2 is mostly due to uptake by the oceans, which will essentially stop when about 25% of what humans have emitted is still in the atmosphere. Atmospheric CO2 concentrations will then very slowly decay back to pre-industrial levels, but this will take something like 100000 years.
So, global surface temperatures should stabilise soon after human emissions get to (net) zero, but they will remain at this elevated level for a very long time.
It’s explained quite well in this Carbon Brief post.
https://www.carbonbrief.org/explainer-will-global-warming-stop-as-soon-as-net-zero-emissions-are-reached/
wmc,
I wasn’t really assuming one, or another, simply making the point that ensuring that our infrastructure keeps improving so that the impact of climate change (or the impact of extreme weather events) continues to go down will require investment in the necessary infrastructure.
I would argue that there is little evidence either way. Extrapolating from the past isn’t great if the future is likely to quite different to the past. If emissions get to (net) zero on a timescale such that future climate change is limited, then continuing to do what we’ve been doing in the past may well continue to reduce the impacts of extreme weather events. If we continue to increase emissions, then we’d expect warming to continue (and possibly accelerate, given the linear relation between emissions and warming) and would expect some extreme events to become more frequent and/or intense. Hence, doing what we’ve done before may not be sufficient. Maybe we’ll get lucky, maybe societies will invest in suitable infrastructure, but it’s not obvious that either will be the case.
“I still do have moments of naivety when I think it might be worth engaging. It rarely is and these moments are much rarer than they used to be.” Too true, from the other side of the fence as well.
Tom,
Indeed, which is one reason why I often don’t see the point in actively trying to bridge these divides. If you’re confident in the position you hold, and are willing to own it, carry on. Might be good if people were then able to acknowledge if they do end up being wrong in some way, but that’s probably expecting too much (in many cases, at least).
I think I have a decent record in admitting error, going back to 2010 when I abandoned climate skepticism for the kinder, gentler (and oh, so infallible) lukewarmism I embrace today. (That’s a joke, willard.)
A lot of the people claiming “there is plenty of evidence that we’ve successfully done so in the past” do appear to regard climate adaptation as free. At the same time, apparently we have no ability to adapt to a carbon tax, which will end the economy as we know it.
Obviously adaptation in some form will continue, but lack of evidence that it won’t stop is not evidence that it will continue in a productive way. It’s already clear that some jurisdictions are playing the “greater fool” game to preserve asset values for incumbents – witness gag orders and climate planning bans in various locales. As nonlinearity or acceleration increases, it seems likely to me that people are going to rely more on counterproductive shortcuts and things will degenerate into musical chairs.
We say that we invest in infrastructures, but we do not say that we invest in adaptation.
I wonder why.
Scratching my own itch, looks like there is no dichotomy between adaptation and infrastructures:
https://www.wri.org/insights/adaptation-finance-explained
The World Resource Institute also counts stronger housing, more drought-tolerant crops, social safety nets, or improved decision-making around climate-related risks.
It would be nice if our Freedom Fighters accepted safety nets as sound investment.
[Jason Box is superb. This video is short and slightly simplified for public consumption, none the worse for that.]
The people glibly championing adaption have no idea how much it will cost; it just sounds easy/cheap, because the non-scientific meaning of the term is about psychologically dealing with changed circumstances. So it doesn’t amount to much more than rhetorical sleight-of-hand.
Also, adaption does not just happen: who is paying for it? The people arguing for the fossil-powered status-quo are adamantly opposed to climate finance going to less well-off nations.
As a champion of adaptation I find myself looking around desperately for others of my ilk saying it will be easy or cheap. When I brought figures to this blog showing that only 20% of climate spend was on adaptation, I thought the general feeling of other commenters was that that was either enough or too much. When I said it should equal the spend on mitigation, my comment was not really welcomed.
I think it was Mosh who first broached the idea that if we spent on adapting to today’s climate and added a safety margin for climate change we’d probably do okay. Maybe I came out with it first. Either way, that idea doesn’t seem to get much traction in these parts.
Tom,
I’m sure that we’ve had this kind of discussion before. I don’t think many who think we should actively try to limit how much is emitted (with caveats) thinks we shouldn’t also adapt. There are many parts of the world that don’t even cope all that well with climate events today, so clearly it’s important to try and reduce the impact of these type of events, both in terms of what we face today and what we might face in the future.
The problem that some have (myself included) with suggestions that we can adapt, is that it will depend on how much the climate does change. If we end up reducing emissions fast enough so that there isn’t much more future warming, then it may well be straightforward to adapt to the resulting changes. However, this would seem to imply effective mitigation strategies were somehow implemented (so, in a sense, it’s implictly suggesting we’ll mitigate, even if this isn’t explicit).
On the other hand, if emissions continue as they are, or even continue to rise for some time, then future warming could be substantial, the change to the climate could also be substantial, and it may be very challenging to deal with the resulting impacts. Of course, we could be lucky and discover that even if emissions keep on rising that the resulting climate change is modest and that it is pretty straightforward to adapt to these changes. That, however, seems somewhat unlikely.
So, I certainly don’t think there is no scenario under which we could adapt to the changes that humanity faces and continue seeing reductions in the impacts, but I’m much less confident that this will be the case than some seem to suggest.
A few clarifications. I keep using “we” above and I realise that there isn’t a single “we” but I don’t really know what other term to use (well, I could probably find other ways to express this, but I’m trying to keep it short). Also, even if it does turn out to be challenging to implementing adaptation measures that reduce the impact of climatic events, that doesn’t mean that I think we shouldn’t try. Clearly a world where we’re tried to reduce the impact (through adaptation and mitigation) would probably be better than one where we didn’t bother.
Maybe I’ll add to the above and point out that the current evidence suggests that the climate (as measured by global average surface temperatures) will continue to change until emissions get to (net) zero and that the overall level of warming will depend on cumulative emissions. Hence, unless you really think that there is no level of warming that has any real chance of seriously challenging humanity’s ability to adapt, there is likely to be a limit to how much more can be emitted if we want to avoid reaching a stage where there are good chance that there will be limits to adaptation.
Obviously, defining where this would be probably be isn’t strictly possible, but current policy pathways seem to taking us towards something like 2.7C +- 1C, so don’t strongly rule out warming of close to 4C. Hence, maybe we should be trying to do somewhat better than this, even if we also need to think about how to adapt to the changes that are probably unavoidable.
I may not have expressed this all that clearly, but I did try to write some posts about this general issue a while ago that may explain things a little more clearly.
Hi ATTP, I guess what frustrates me a little is that I know exactly zero people who say that we should adapt and only adapt.
Tom,
I didn’t say there are people who say we should adapt and only adapt. What I see are people (Lomborg, Nordhaus, for example) who seem to be arguing that we will be able to adapt. In other words, they’re not necessarily explicitly arguing against mitigation, but they do seem to be suggesting that we shouldn’t be too concerned because even if we don’t reduce emissions particularly quickly, it won’t be too big a deal because historical trends suggest that we will be able to adapt to whatever changes might occur.
I’m not suggesting that they’re definitely going to be wrong (we can’t really be certain about the future), but I’m not nearly as confident as they seem to be, partly because there may well be adaptation limits, and partly because even if it is true in some regions of the world, it may not be true in all.
Thanks aTTP, and I apologise for not reading similar comments and replies already posted. I do find this surprising, though, given the large excess in CO₂ and the slow uptake by natural sinks.
> they’re not necessarily explicitly arguing against mitigation
Bjorn argues quite explicitly against it, by stating we need to prioritize other things. Junior and Judy are indeed arguing against it when they argue that to limit emissions will have little impact on immediate temperatures.
We’ve been over this two-step tango so many times already. Here’s where Very Tall compared Bjorn’s laundry list to the freaking report Climateball players ought to read but never do:
Source: https://andthentheresphysics.wordpress.com/2015/04/24/lomborg-science/#comment-54512
Notice the date.
We’ve been over this so many times already that we’re past any concern regarding miscommunication.
Otto,
Initially we would expect the uptake to be reasonably, and then slow down. Figure 1 and 2 of this paper illustrate it quite nicely.
Click to access archer.2009.ann_rev_tail.pdf
From 2011 to 2020, global agricultural productivity grew at an average of just 1.12 percent per year, a significant drop from the average growth rate of 1.99 percent from 2001 to 2010.
After reaching a peak of 2.1% in 1963, the global population growth rate has been steadily declining. In 2023, the global population growth rate is estimated to be 0.88%.
So the threat is not current.
The impacts of climate change on agricultural productivity are a serious threat to global food security. To meet the needs of a growing population, agricultural production must increase. However, climate change is making it more difficult for farmers to produce food.
There are a number of things that can be done to address the threat of climate change to agricultural productivity. These include:
Improving agricultural practices: Farmers can adopt climate-smart agricultural practices that help them to adapt to the impacts of climate change and reduce their vulnerability to extreme weather events. These practices include planting drought-tolerant crops, using water-efficient irrigation methods, and diversifying crop rotations.
Investing in research and development: There is a need for more research and development into climate-smart agricultural practices and technologies. This research will help farmers to adapt to the impacts of climate change and increase their productivity.
Implementing policies that support sustainable agriculture: Governments can implement policies that support sustainable agriculture. These policies can include providing financial assistance to farmers, investing in agricultural research, and promoting the use of climate-smart agricultural practices.
Oh–sorry, all. That’s just adaptation…
Sorry again–I didn’t credit Bard for its contributions.
Tom,
I’m not entirely sure what point you’re trying to make. You seem to be doing pretty much what I suggested some do in this comment. I also don’t think many would object to Improving agricultural practices:, Investing in research and development: , or Implementing policies that support sustainable agriculture: .
> At the same time, apparently we have no ability to adapt to a carbon tax, which will end the economy as we know it.
Fear-mongering about fear-mongering has been a big part of the game for as long as I’ve been observing it.
Rather how like models are crap unless they show results we agree with.
Or global temperatures don’t exist except if there’s a “pause.”
Or peer-review is pal review unless they’re our pals or we like the results.
The list is endless.
Tom –
Do you mind explaining what rationale you used to cherry-pick that list of things we could do to address future food pressures?
Willard –
> We’ve been over this so many times already that we’re past any concern regarding miscommunication.
But “denier.”
Hi ATTP, yes, we have had this and similar conversations several times in the past. Mitigation is needed and I certainly do not begrudge any money spent on it. But so is adaptation–and I would argue in equal measure.
I have repeatedly argued that infrastructure build and repair could easily and efficiently add a margin to prepare for climate change. But the cold fact is that people are dying from weather today and whatever label we choose to use, their needs should be addressed today.
Lomborg’s priorities do not match my wish list to any great degree, but I agree with him on one important thing–that neither mitigation nor adaptation should exist apart from the other pressing needs faced by so many. Some in the climate conversation will tell me that they are not arguing to exclude other issues–but focus and emphasis tell a different story.
Every issue has ‘single issue proponents’ (and opponents too, I guess), so I can’t complain about those devoted to tackling climate change. But although I support your efforts I cannot join you wholeheartedly–other issues are important too and (of course, as a lukewarmer) I truly think you overestimate the threat it poses.
Tom,
I think you rather misunderstand my views, and I really don’t know what you think you’d be joining. Just because I happen to write a lot about climate change doesn’t mean I think it is some kind of single dominant issue that we should tackle above all else. There are, of course, other issues that are also important and I have a lot of respect for those who spend there time trying to deal with these issues. My intention is not to discourage them from doing so.
In my view there’s a vast difference between those who are actively trying to find solutions to all the various problems we face, and those who seem to think we shouldn’t worry because everything will somehow be fine.
Then we are broadly on the same page. Maybe at different paragraphs…
Re, “they’re not necessarily explicitly arguing against mitigation” – actually, I think Nordhaus is for all practical purposes arguing against significant mitigation effort. He proposes a very low social cost of carbon ($31/Ton CO2 here for example https://www.pnas.org/doi/10.1073/pnas.1609244114 ). In the original DICE model, it was even lower, and the “optimal” emissions reduction trajectory was only a little below BAU. The low number is substantially a consequence of discounting the welfare of future generations, but also other rosy assumptions about damage functions and capital flexibility. I don’t find it credible to say that one is all for mitigation, as long as we don’t actually try.
I’m more inclined towards half our efforts on reducing emissions, mostly now and half on adaptation, mostly later. The emissions reductions reduce the costs of adapting but investment in adapting doesn’t reduce the costs of emissions reductions.
Our infrastructure, including grid components, is aging today, so replacing what’s falling apart with non-fossil systems isn’t just spending on “mitigation” since we keep getting power, more reliably, as the result. Since we would be replacing thermal plants with other tech, less subject to failing in temperature extremes, it’s kind of like spending on “adaptation” too.
Where to find the money? The following is about a new model developed that applied experience curves to the renewable technologies, to end the severe overestimation of costs that has been the rule previously. We save trillions by speeding up the energy transition.
“Empirically grounded technology forecasts and the energy transition” Joule, September 2022 (Open access)
https://www.cell.com/joule/fulltext/S2542-4351(22)00410-X
“we find that compared to continuing with a fossil fuel-based system, a rapid green energy transition is likely to result in trillions of net savings. Hence, even without accounting for climate damages or climate policy co-benefits, transitioning to a net-zero energy system by 2050 is likely to be economically beneficial.”
One of the authors also has a new article about it in American Scientist
https://www.americanscientist.org/article/modeling-a-greener-future
It’s probably paywalled, but he notes examples of severely conservative assumptions built into many of the energy costing models – here’s one:
“For example, in 2015 an influential model from one of the top international modeling teams limited solar and wind to providing a maximum of 20 percent of the power in the electricity grid. But in 2023, those sources routinely provide more than 60 percent of the power in large economies such as the United Kingdom and Germany.”
So more money becomes available if we invest in decarbonizing fast than if we go more slowly. Think of the trillions spent on fossil fuel supplies that will instead be freed up by not needing fuels. Not to mentioned reduced healthcare costs from air pollution (well, when wildfire smoke isn’t local).
Tom,
I was actually referring to Ted Nordhaus of the BTI, rather than his uncle, William.
Estimates of “damages” already include very large amounts of adaption: a huge chunk of the “damage” in early-W.-Nordhaus is people increasing air-conditioning use, rather than sitting in the sun with a stiff upper lip.
So this is in the very earliest work, not something “alarmists are ignoring”.
The significant amount of adaption+suffering in original-DICE is partly because mitigation looked so expensive a couple of decades ago; given that estimates of mitigation costs have reduced, this obviously tilts the balance towards doing more mitigation, and less adaption+suffering.
In original DICE, mitigation cost is .0686*reduction^2.887. So reduction=1 (i.e. 0 emissions) is pricier than you might expect if there’s endogenous tech or other externalities are priced in, for example. However, at the optimal reduction – roughly 12% in the base case – mitigation cost is totally negligible, as is the marginal product of carbon. Halving the scale of the mitigation cost increases the optimal reduction by 50%, but the equivalent SCC is still very low. This is not really a product of the mitigation side of the system; it’s from the carbon/climate/damage function. Damages are low because carbon isn’t conserved and Nordhaus recalibrated the Schneider-Thompson model to have a thicker mixed layer and therefore longer delay, due to the damage function itself, and most of all due to the strong time preference on welfare.
Indeed, original-DICE does so little mitigation that the result is not very sensitive to adjusting the mitigation cost by itself. The mitigation cost curve is a key ingredient in getting a reasonable result, but only plays a substantial role once you have set the discount rate to a reasonable value.
Silly me! Gonna bring up methane again. It does seem to be on topic as something rather non-linear. https://www.livescience.com/planet-earth/climate-change/we-could-be-16-years-into-a-methane-fueled-termination-event-significant-enough-to-end-an-ice-age?utm_term=C28B497D-FD1F-49B8-8E1B-40011F813BD5&utm_campaign=368B3745-DDE0-4A69-A2E8-62503D85375D&utm_medium=email&utm_content=7A62E4E1-0374-461B-9ED3-9C7933340AC7&utm_source=SmartBrief