ZOMG catastrophe, part n

PXL_20220731_113815293 Or, Climate endgame: risk of human extinction ‘dangerously underexplored’. The latest fad is to argue about the tone of reporting, and complain about or push "doomerism", as an alternative to doing anything useful. Although since the people doing the chattering aren't capable of doing anything useful - that tends to come from the people doing solar panels and windmills - perhaps it is all harmless enough1. It comes from Climate Endgame: Exploring catastrophic climate change scenarios featuring that nice Tim Lenton.

Anyway, I got as far as We know that temperature rise has “fat tails”: low-probability, high-impact extreme outcomes (9) before giving up. Because: ref 9 is, and I kid you not, G. Wagner, M. L. Weitzman, Climate Shock: The Economic Consequences of a Hotter Planet (Princeton University Press, 2015). FFS: it is a pop-sci book. You can't use that as a ref in a serious paper; therefore, this isn't a serious paper.


1. Harsh and not fair; I exaggerate for effect.


With all the hype about the heatwave, it’s worth having a bit of perspective - JA. Heat vs Cold deaths. And a reply from Gavin. And an ACX post; thanks A.

China Is on Track to Double Its Solar Panels From Last Year’s Record

* VV: WATN: The 10th anniversary of the still unpublished Watts et al. (2012) manuscript. Includes actual real data from Coppa 2021. See-also Moyhu.

* Gavin attempts to shortcut the problem, but it doesn't work.

The best case for worst case scenarios: Gavin, 2019.

Reto Knutti seems sane.

* Open Posts, Closed Works, Other Worlds: part 3 - Rich Puchalsky

The Skull Beneath the Skin - Hayek and Atavism; Q: if I look in antient Greek plays, do I find warnings of this?


Anteros said...

On your little heat v cold deaths thing, I'm rather with Gavin. Unless a study explicitly teases out deaths due to actual cold, I'll assume it's talking about winter deaths - very little connection with temperature.

If I remember Scott A's deepish dive into this, there's an interesting correlation between winter temps and excess deaths. Interesting because the colder the winter temps, the fewer excess deaths.. Beware places with mild winters :)

P.S. https://astralcodexten.substack.com/p/chilling-effects

William M. Connolley said...

Thanks for the ACX link; that's what I'd been wanting to find / remember. What I kinda took from that was that Yes there are more cold deaths than warm ones, But that most of those are deaths-that-happen-in-winter, and aren't particularly associated with degree of cold, and aren't exacerbated by more cold, or fixed by less cold (although that last point might be dubious and I might have made it up).

Anteros said...

I think yes to the last bit - a modicum of winter warming will do very little to excess winter deaths.

Your link to Gavin's tweet reminds me of some bafflement I have about the idea of net-zero From the sensible perspective of a carbon tax implemented at (obviously) the social cost of carbon, once its in place we can all go home and argue about something else (It won't ever be implemented, but still) After the tax is set, all carbon emissions are, theoretically at least, optimum ones - the tax itself distinguishes between those emissions that make us better off, and those that make us poorer.

But the net-zero framing completely misunderstands this - it denies that some fossil fuel burning can be net beneficial. Is this not nuts? If there was no fossil fuel burnt at all and somebody decided to back up their hospital electricity supply with a diesel generator, the net benefit might be per ton of carbon.

Surely there is an optimum amount of carbon to be burnt, and double surely it isn't zero?
Doesn't net-zero imply that the social cost of carbon is infinite?

Unknown said...

Typo - The net benefit might be (insert very large number of £ here) per ton of carbon.

William M. Connolley said...

> Doesn't net-zero imply that the social cost of carbon is infinite?

I've never been too sure exactly what people mean by net-zero. If it meant, "you can burn fuel as long as you capture some CO2" (which would be the obvious implication of "net") then hospitals can still run backup generators, and pay for sequestration.

OTOH https://www.un.org/en/climatechange/net-zero-coalition says What is net zero? Put simply, net zero means cutting greenhouse gas emissions to as close to zero as possible, with any remaining emissions re-absorbed from the atmosphere, by oceans and forests for instance which is something different, and contains the undefined "as close to zero as possible". Probably, they are afraid that emphasising the "net" rather than the "zero" will make people make unrealistic assumptions about sequestration. Although we're currently so far off target that this is irrelevant.

Phil said...

> Doesn't net-zero imply that the social cost of carbon is infinite?

Social cost of carbon isn't constant. The more carbon released, the higher the social cost of carbon. It might go nearly infinite, if the damages get as large as say the Permian Triassic event.

Replaying the PT wouldn't be a great future.

Anteros said...


No - the social cost of carbon includes future releases and future damages. It cannot rise merely as a result of more carbon being released. It may rise if the estimate is wrong, but then again, it may also fall.

If Nordhaus and Tol (and even Stern) are in the right ballpark with £50 per ton, then that will always be the social cost of carbon. If new information shows that they are wrong, then it will be adjusted (either up or down)

William M. Connolley said...

> the social cost of carbon includes future releases and future damages

I don't think that is possible. The SSC of a tonne released now depends on how much is released in the future. To take an extreme example, the SSC for a tonne released in 1800, if none were subsequently released, would be zero; but since more was released, the (true) SSC in 1800 is about what it is now. So to speak. This would be a problem if we had carbon taxes anywhere near the true level; but since we're nowhere near that I feel free to largely ignore the issue.

Anteros said...

> The SCC of a tonne released now depends on how much is released in the future.

Of course, but don't estimates of the SCC include estimates of the amount released in the future? If damages are estimated to be, say, a £trillion, the SCC will be that amount divided by the number of tonnes released. How otherwise would you get a number like £50 per tonne?

William M. Connolley said...

If you estimate the future and get it right, then I think that is so. But the chances of getting it so right are low, so changes in the SSC price (driven by reality, rather than just whim) are likely. Depending on how far into the future you're thinking of.

Anteros said...

Agree with that - as I said to Phil, adjustments may be needed, and not necessarily upwards. But it's that acting under uncertainty thing - make the best estimate, act accordingly, and be prepared to make changes.

What I disagree with is the idea that PT extinction-type events are plausible and so decarbonisation has to happen by tomorrow afternoon, irrespective of the cost.

Tom said...

At the risk of repeating what I repeated repeatedly 7 years ago, there is also and obviously a social cost of removing carbon. I do not see this included in many (any?) discussions of the subject.

William M. Connolley said...

Dunno wot you mean guv. SSRC == -SSC, for deltas around current levels. No?

Phil said...

PT event happened at the PT. We do know about how much carbon was released to cause it, and of course at this distance in time the details are blurry.

Why would basically the same event _not_ replay with the same cause (with a different carbon source)?

We don't get there til late this century the very earliest, and probably well later.

...and Then There's Physics said...

I had a chat with Chris Hope once about the calculation of the SCC. IIRC, the SCC of a tonne of emission today does not depend on the future emission pathway. As I understand it, the SCC of emissions today is based on the impact of the warming due to that emission, which depends on the warming that has occurred prior to that emission and on how much additional warming will occur due to that emission happening now (and, obviously, the impact of that additional warming).

The reason that the SCC rises with time is because a tonne emitted in the future when the world will be warmer does more damage, or is calculated to do more damage, than a tonne emitted today or than a tonne emitted in the past. So, if one was to implement some kind of carbon tax then - ideally - it should change with time and should depend on how emissions evolve. If emissions keep rising, a carbon tax should increase faster than if emissions were to stabilise and start falling.

That's my understanding, at least, which may (of course, be wrong).

Anteros said...

That makes a fair amount of sense, although I confess to not being 100% convinced. Rather odd that it isn't more obvious, and obviously well-known.

Perhaps someone can ping R Tol - he could probably clear up any confusion in a sentence or two.

If my understanding is completely squiffy, I'd quite like to know about it.

@Phil I can't take "PT-type event incoming from the end of C21" even vaguely seriously. I'll go with the IPCC suggesting that compared to other variables (like demographics, technology change, politics etc) CC impacts will be "small". Measurable perhaps, noticeable even, but "small".

William M. Connolley said...

I don't think that does make sense. Wiki tells me that the SSC is The social cost of carbon (SCC) is the marginal cost of the impacts caused by emitting one extra tonne of greenhouse gas (carbon dioxide equivalent) at any point in time, inclusive of 'non-market' impacts on the environment and human health. But you can't calculate that marginal cost without knowing the future CO2 levels (unless damage is linear but it isn't).

Anteros said...

So either ATTP's recollection of something C Hope said to him a while ago is erroneous. Or a Wiki editor has been misinformed...

The difference is quite dramatic - either a correctly estimated carbon tax will remain at the same level in perpetuity. Or it will rise ominously without end.

William M. Connolley said...

Ah, no; what I said doesn't imply that the SSC is constant in time. In 20 years time the CO2 levels will be higher, thus the discount-weighted future marginal costs of the extra CO2 is higher.

...and Then There's Physics said...

In 20 years time the CO2 levels will be higher, thus the discount-weighted future marginal costs of the extra CO2 is higher.

Maybe you can explain your argument here. According to the TCRE, every tonne of CO2 emitted produces the same warming (i.e., ~1.8C per 1000GtC). My understanding of why the SCC increases with time is because a tonne emitted in the future is emitted into a world that is warmer than it was before, hence the warming due that tonne does more damage than each individual tonne that has already been emitted.

If this is the case, then we can estimate the SCC for every tonne emitted because we know how much warming each tonne will cause and we also know how warm it is when tonne N is emitted because we can calculate how much warming occured due to the N-1 tonnes emitted before tonne N. What we don't know in advance is the rate of emissions. Hence, the rate at which the SCC will rise depends on the pathway, but the relationship between SCC and how much has been emitted does not. Again, I could be wrong about this.

So, I think we expect the SCC to rise with time under all plausible emission scenarios, but it doesn't have to rise forever, because we can (will?) eventually stop emitting.

William M. Connolley said...

Yes, exactly. But that means we need to know / estimate future levels to calc SSC of curent emissions.

...and Then There's Physics said...

I'm still not following why you need to know/estimate futures levels to calc SSC of current emissions, unless you mean the future CO2 levels resulting from today's and earlier emissions.

William M. Connolley said...

Errr, I'm running out of ways to explain this. We agree that damages-per-CO2 go up, as the CO2 level increases: you agree with this, because you know that the SSC will increase into the future. Therefore, the level of CO2 in the future (and hence future emissions, as well as past and present) is part of the calculation of the SSC of CO2 emitted today.

To simplify, suppose all the costs comes 20 years in the future, and the cost is X if the CO2 level at that point is Y, and X*n^2 if the level is n*Y. Then, into order to calculate the cost - X*n^2 - you need to know n. No? (I'm throwing in the non-linearity in case the "marginal" bit means I need it...).

Gator said...

The claims of an excess of 60,000 deaths in winter seems grossly exaggerated.


This seems to show <200 excess deaths in England in Wales each year for 2018 and 2019 with a huge jump due to Covid in 2020. But maybe to 1100 excess winter deaths in total. 60K is stupidly, wildly off.

And anyway, who the f cares? Is this turning into one of those "global warming is good because plants like it warmer" or somesuch? You don't think that a changing climate will have other knock-on effects that will make the winter deaths (assuming that they actually do go away, because it was the cold winter, and not something like covid) look insignificant?

William M. Connolley said...

Are you talking about the same things? The Twit says "60,753 deaths associated with cold", not "excess".

> who the f cares?

You do, since you posted :-). I think it is obvious that "a changing climate will have other knock-on effect" but that doesn't make it excusable to avoid looking at evidence one dislikes. As to "make the winter deaths... look insignificant" I think it unlikely we'll be seeing 60k+ deaths / year from warming in the UK any time soon. RP Jr refers.

Phil said...

@Anterosl The iPCC refused to consider ice sheet abrupt collapse until recently, and that is nearer term. Not rejected, just not mentioned. Even though this has been discussed for decades.

Do you do agree that a PT event happened?

Phil said...

Oh, and how much CO2 did it take?


Sun is hotter now, so would need less now, yes?

Oh, this was enough, and likely more than enough.

How much less would have a similar impact?

Gator said...

Hmm, I'm a dunce. I didn't read the whole link I put up. This link does claim:
"An estimated 63,000 excess winter deaths occurred in England and Wales in winter 2020 to 2021, 6.1 times higher than winter 2019 to 2020; the growth was mostly driven by the large number of coronavirus (COVID-19) deaths in the non-winter months of 2020 (April to July) and the winter months of 2021 (December to March)."

The graph I was looking at was an excess mortality index, not excess mortality.
Note though that they don't claim that the excess deaths have anything to do directly with cold - the surge in excess deaths was driven by covid. Even taking that out, most excess deaths are in hospitals, and most excess deaths in London.

My theory would be that deaths increase in winter because of the lack of light and low cloud cover. ;) Nothing to do with cold.

Anteros said...


If you're interested in the whole excess deaths due to cold/winter thing, there's a good investigation by a non-partisan here


Gator said...

@Anteros, thanks, I'll take a look.

...and Then There's Physics said...

I found Chris Hope and David Newberry's paper about Calculating the Social Cost of Carbon which says in Section 3.2
The PAGE model calculates the social cost of carbon (SCC) by finding the difference in the discounted economic cost of climate change impacts between two emission scenarios that are identical except for the emission of an extra one billion tonnes of carbon as CO2 in 2001 for one of the scenarios.

Section 3.3 then considers the growth of the SCC over time and says:

They increase for the simple reason that as we get closer to the time when we expect the most severe impacts of climate change to occur, then the extra impact from putting another tonne into the atmosphere gets higher

Section 3.4 then seems to suggest that the SCC is invariant with emission scenario, although admittedly they only seem to test two scenarios. They do have a discussion about why it seems invariant and suggests it's to do with the interplay
between the logarithmic relationship between radiative forcing (i.e. the global warming
effect) and concentration (which will tend to make one extra tonne under the A2 scenario
cause less impacts), the non-linear relationship of impacts to temperature (which will tend to make one extra tonne under the A2 scenario cause more impacts), and discounting (which will tend to make early impacts more costly than late impacts).

Although, having read this I now wonder if it isn't wrong. It seems that the above is arguing that one extra tonne in a high emission scenario produces less warming than an extra tonne in a low emission scenario because of the logarithmic relationship concentration and forcing. This is then balanced by the greater impact in the high emission scenario, and then discounting.

However, the TCRE suggests that each tonne produces the same level of warming, and hence warming due to one extra tonne in a high emission scenario should (I think) have a greater impact than the same dT in a low emission scenario (which may have been what WMC was pointing out).

So, it seems that Chris Hope's paper does suggest that it doesn't depend on emission pathway, but I'm not entirely convinced that his argument for why this is the case is correct.

Phil said...

The damage model used is (Hope C, (2006), (A.2)): "Impacts are assumed to occur only for temperature rise in excess of some tolerable rate of change, TR d,r , or that has magnitude above the tolerable plateau, TP d,r ."


Assumptions make an ass out of u and me.

While an assumed damage function is probably necessary for a simple IAM, I doubt that it is a good match for reality. Past climate changes and their impact on economies should be studied, and what ever damage function needs to be rooted in observations, not assumptions. Unraveling past cultural changes partly forced by climate changes seems complex, to say the least. Most of the recent past climate change has been fairly subtle on a global scale when compared with future climate change. This isn't easy.

A drought starting in 1130 first expanded the Ancestral Pueblo culture, leading to larger settlements, some of the finest pottery ever made and then the total collapse and abandonment of large areas. Yet of course we can't know in general if past larger cities were better places to live, or if the elite just lived better in these larger cities, as we mostly find goods and buildings that the elite used. Those that had less might well have left less of a record. The non-elite might be better off after the cities were abandoned. Fitting a collapse of a complex society into a simple equation or three seems challenging, at best.

Might want to read Collapse of Complex Societies by Joseph A. Tainter

His conclusion is at least wrong enough to be interesting.

Phil said...

Arctic continues warming faster than modeled.


This is a long running problem, climate models generally don't reproduce geologic records of past very hot periods.

So I doubt that future very hot periods are accurately modeled.