mchr3k

Cli­mate Change: Known Un­knowns, Ques­tion­able Sub­sti­tutabil­ity, and Look­ing Beyond Car­bon Taxes

• mchr3k 26 Jul 2023 11:15 UTC

  2 points

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  on: Cap­i­tal­ism, power and episte­mol­ogy: a cri­tique of EA

  I just wanted to leave a quick note to thank you for writing such a thoughtful and well researched piece on this important topic ❤️

• mchr3k 5 Nov 2021 8:56 UTC

  3 points

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  in reply to: SammyDMartin’s comment on: Good news on cli­mate change

  There are a couple of sources which I’d recommend taking a look at.

  • 2015 Climate Change Risk Assessment—particularly worth reading the section which includes the quote “A simple conclusion is that we need to know more about the impacts associated with higher degrees of temperature increase. But in many cases this is difficult. For example, it may be close to impossible to say anything about the changes that could take place in complex dynamic systems, such as ecosystems or atmospheric circulation patterns, as a result of very large changes very far into the future.”

  • Climate change risk assessment 2021 - conclusion starts out by saying “Unless NDCs are dramatically increased, and policy and delivery mechanisms commensurately revised, many of the climate change impacts described in this paper are likely to be locked in by 2040, and become so severe they go beyond the limits of what nations can adapt to.” Section 4 of this paper considers various cascading systemic risks. These are a big part of what makes predicting the future impacts of climate change so hard.

• mchr3k 14 Jul 2020 22:52 UTC

  2 points

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  on: An­no­tated List of EA Ca­reer Ad­vice Resources

  I have been working on an EA aligned resource titled “Working on Climate Change as a Technologist” which I’ve started sharing with a few folks.

• mchr3k 28 May 2020 22:23 UTC

  2 points

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  in reply to: Will Bradshaw’s comment on: Cli­mate Change Is Ne­glected By EA

  The claim that climate change is a major PR issue for EA, if true, is evidence that EA’s position on climate change is (in at least this one respect) correct.

  I’d like to extend my previous model to have three steps:

  (1) EA downplays the impact of climate change (e.g. focusing on x-risk, downplaying mainstream impacts).

  (2) EA downplays the value of working on climate change (e.g. low neglectedness, low tractability).

  (3) EA discourages people from working on climate change in favor of other causes.

  I think you are arguing that since lots of people already care about climate change, (3) is a sensible outcome for EA. To put this more explicitly, I think you are supportive of (2), likely due to you perceiving it as being not neglected. As I’ve stated in this post, I think it is possible to argue that climate change is not actually neglected. In fact you suggested below some good arguments for this:

  “Even though lots of work has gone into solving climate change, the problem is so vastly complex and multidimensional that there’s still lots of low-hanging fruit left unpicked, so tractability remains high (and scale is large, so the two together are sufficient for impact).”

  “Although lots of work has gone into solving climate change, partial solutions aren’t very valuable: most of the impact comes from the last few % of solving the problem. Also [for some reason] we can’t expect future work to continue at the same rate as current work, so more marginal work now is especially valuable.”

  “While lots of resources have already gone into solving climate change, the problem is actually getting bigger all the time! So even though neglectedness is low and falling, returns from scale are high and rising, so marginal work on the problem remains valuable.”

  But let’s put that to one side for a moment, because we haven’t talked about (1) yet. Even if you think the best conclusion for EA to make is (3), I still think it’s important that this conclusion is visibly drawn from the best possible information about the expected impacts of climate change. Sections (1), (4), (5), and (7) in my post speak directly to this point.

  I look at the way that EA talks about climate change and I think it misses some important points (particularly see section (4) of my post). These gaps in EA’s approach to climate change cause me to have lower trust in EA cause prioritization, and at the more extreme end make me think “EA is the community who don’t seem to care as much about climate change—they don’t seem to think the impact will be so bad”. I think that’s a PR issue for EA.

• mchr3k 28 May 2020 0:05 UTC

  6 points

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  in reply to: kbog’s comment on: Cli­mate Change Is Ne­glected By EA

  That’s fine. Marginal/​social cost of carbon is the superior way to think about the problem.

  (A) Carbon budgets express an important idea about continued emissions committing us to particular levels of warming. This is particularly important when we are likely to exceed the 1.5C carbon budget in less than 10 years. (B) The 80K Hours problem problem also doesn’t mention marginal/​social cost of carbon. (C) Social cost of carbon is usually computed from an IAM, a practice which has been described as such:

  “IAMs can be misleading – and are inappropriate – as guides for policy, and yet they have been used by the government to estimate the social cost of carbon (SCC) and evaluate tax and abatement policies.” [Pindyck, 2017, The Use and Misuse of Models for Climate Policy]

  In any case, my estimate of the long-term economic costs of climate change (detailed writeup in Candidate Scoring System: http://​​bit.ly/​​ea-css ) aggregates over the various scenarios.

  I reviewed your writeup, focusing on pages 47 − 61 and I have some questions/​comments.

  Short term impacts (page 56):

  • I see that you use GWWC’s estimate of tonnes of CO2 per life saved. I critiqued GWWC’s approach in this previous post.

  • “40% of Earth’s population lives in the tropics, with 50% projected by 2050 (State of the Tropics 2014) so we estimate 6 billion people affected (climate impacts will last for multiple generations).”—The world population is expected to be ~10 billion by 2050, so 50% would be 5 billion. How are you accounting for multiple generations?

  • “We discount this to 2 billion to account for the meat eater problem”—What is the meat eater problem?

  • “If each of them suffers −1 QALY over their lifetime from climate change on average”—why did you choose −1 QALY?

  • ″… the total impact would be 550,000 QALYs per year. However, the reality could be worse because of increases in temperature variance. And we must add to this the other short-run costs of air pollution. They seem plausibly greater than the short-run costs of climate change, especially for the American middle and upper classes. So as a very rough guess, we estimate a weight of 2.15million QALYs per year.”—Why did you choose to multiply 550 by ~3.9?

  Long run growth (page 56, 57)

  • “yields an expected cost of 11% of GWP from climate change (driven substantially by tail risks of extreme climate change with the assumption of quadratic damages)”—Why did you choose to use the “expected cost”? Is there a way to compute the probability of impact >= 20%, or >= 30%? That would help me understand the likelihood of the more severe outcomes.

  • As a general comment, this section seems to rely heavily on economic models which rely on IAMs. See my comment above for reasons to be skeptical about the results of IAMs.

  If you think that people will like EA more when they see us addressing on climate change, why don’t you highlight all the examples of EAs actually addressing climate change (there are many examples)

  Appendix 1 lists many of the more recent EA engagements with climate change. I agree that EA has not ignored climate change. However, the point of this post was to discuss some trends which I have observed in how EA engages with climate change.

  In any case, estimating the damages of climate change upon the human economy has already addressed by multiple economic metanalyses. Estimating the short- and medium-term deaths has been done by GWWC.

  There are legitimate causes for concern about both of the sources you cite—the first relies on IAMs, GWWC relies on one 2014 WHO publication which has some important limitations.

  Climate change being expected to persist for centuries is conditional upon the absence of major geoengineering. But we could quite plausibly see that in the later 21st century or anytime in the 22nd century.

  I agree that this is a plausible possibility, but not one which I’d like to have to rely on.

  If we can’t stay under 1.5C, we might stay under 2.0C, which is not that much worse.

  That depends on what you count as “not that much worse”. The IPCC SR15 report predicts that hundreds of millions more people will be severely impacted at 2.0C versus 1.5C.

  I find this whole genre of post tedious and not very useful. If you think climate change is a good cause area, just write an actual cause prioritization analysis directly comparing it to other cause areas, and show how it’s better! If that’s beyond your reach, you can take an existing one and tweak it.

  [...]

  I haven’t read those previous posts you’ve written

  [...]

  Pick another cause area that’s currently highlighted, compare it to climate change, and show how climate change is a more effective cause area.

  I already did that: “Review of Climate Cost-Effectiveness Analyses”. I would love to get your feedback on that post.

• mchr3k 27 May 2020 22:58 UTC

  3 points

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  in reply to: Will Bradshaw’s comment on: Cli­mate Change Is Ne­glected By EA

  For comparison, on 80K’s website right now, AI risk, global priorities research and meta-EA are currently at 26, biosecurity and ending factory farming are at 23, and nuclear security and global health are at 21. So your implicit claim is that, on the margin, climate change is less important than AI and GPR, slightly more important than biosecurity and farmed animal welfare, and much more important than nuclear security and global health (of the bednets and deworming variety). Does that sound right to you? That isn’t a gotcha, I am genuinely asking, though I do think some elaboration on the comparisons would be valuable.

  That does sound about right to me.

  If oodles of smart, motivated young people are super-excited about climate change work, a decent chunk of them will end up doing climate change work. We’re proposing that these are the sorts of people who would otherwise make a good fit for EA, so we can assume they’re fairly smart and numerate. I’d guess they’d have less impact working on climate change outside EA than within it, but they won’t totally waste their time. So if there are lots of these people, then lots of valuable climate change work will be done with or without EA’s involvement. Conversely, if there aren’t lots of these people (which seems false), the fact that we’re alienating (some of) them by not prioritising climate change isn’t a big issue.

  My claim is that EA currently (1) downplays the impact of climate change (e.g. focusing on x-risk, downplaying mainstream impacts) and (2) downplays the value of working on climate change (e.g. low neglectedness, low tractability). If you agree that (1, 2) are true, then EA is misleading its members about climate change and biasing them to work on other issues.

  Perhaps I have misunderstood your argument, but I think you’re saying that (1, 2) don’t matter because lots of people already care about climate change, so EA doesn’t need to influence more people to work on climate change. I would argue that regardless of how many people already care about climate change, EA should seek to communicate accurately about the impact and importance of work on different cause areas.

• mchr3k 26 May 2020 23:08 UTC

  2 points

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  in reply to: Will Bradshaw’s comment on: Cli­mate Change Is Ne­glected By EA

  My guess is that people should probably say what they believe, which for many EAs (including me) is that climate change work is both far less impactful and far less neglected than other priority cause areas, and that many people interested in having an impact can do far more good elsewhere.

  Rather than “many EAs”, I would say “some EAs” believe that climate change work is both far less impactful and far less neglected than other priority cause areas.

  I am not one of those people. I am currently in the process of shifting my career to work on climate change. Effective Altruism is a Big Tent.

• mchr3k 26 May 2020 22:56 UTC

  4 points

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  in reply to: Linch’s comment on: Cli­mate Change Is Ne­glected By EA

  That’s a fair point. As per the facebook event description, I was originally asked to discuss two posts:

  • Louis Dixon—Does climate change deserve more attention within EA?

  • Me—Updated Climate Change Problem Profile

  I ended up proposing that I could write a new post, this post. The event was created with a title of “Is climate change neglected within EA?” and I originally intended to give this post the same title. However, I realized that I really wanted to argue a particular side of this question and so I posted this article under a more appropriate title.

  You are correct to call out that I haven’t actually offered a balanced argument. Climate change is not ignored by EA. As is clear in Appendix A, there have been quite a few posts about climate change in recent years. The purpose of this post was to draw out some particular trends about how I see climate change being discussed by EA.

• mchr3k 26 May 2020 22:44 UTC

  3 points

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  in reply to: Stephen Clare’s comment on: Cli­mate Change Is Ne­glected By EA

  Thanks for your comments and for linking to that podcast.

  And while you may be right that it’s a bit naive to just count all climate-related funding in the world when considering the neglectedness of this issue, I suspect that even if you just considered “useful” climate funding, e.g. advocacy for carbon taxes or funding for clean energy, the total would still dwarf the funding for some of the other major risks.

  In my post I am arguing for an output metric rather than an input metric. In my opinion, climate change will stop being a neglected topic when we actually manage to start flattening the emissions curve. Until that actually happens, humanity is on course for a much darker future. Do you disagree? Are you arguing that it is better to focus on an input metric (level of funding) and use that to determine whether an area has “enough” attention?

• mchr3k 26 May 2020 22:20 UTC

  9 points

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  in reply to: Will Bradshaw’s comment on: Cli­mate Change Is Ne­glected By EA

  Thanks for your feedback.

  Framing climate change as the default problem, and working on other cause areas as defecting from the co-ordination needed to solve it, impedes the essential work of cause-impartial prioritisation that is fundamental to doing good in a world like ours.

  I think it’s worth emphasizing that the title of this post is “Climate Change Is Neglected By EA”, rather than “Climate Change Is Ignored By EA”, or “Climate Change Is the Single Most Important Cause Above All Others”. I am strongly in favor of cause-impartial prioritisation.

  In “Updated Climate Change Problem Profile” I argued that Climate Change should receive an overall score of 24 rather than 20. That’s a fairly modest increase.

  This post itself argues that EA is losing potential members by not focusing on climate change. But this claim is in direct tension with claims that climate change is neglected. If there are droves of potential EAs who only want to talk about climate change, then there are droves of new people eager to contribute to the climate change movement. The same can hardly be said for AI safety, wild animal welfare, or (until this year, perhaps) pandemic prevention.

  I don’t agree with this “direct tension”. I’m arguing that (A) Climate Change really is more important than EA often makes it out to be, and that (B) EA would benefit from engaging with people about climate change from an EA perspective. Perhaps as part of this engagement you can encourage them to also consider other causes. However, starting out from an EA position which downplays climate change is both factually wrong and alienating to potential EA community members.

• mchr3k 26 May 2020 22:10 UTC

  3 points

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  in reply to: UriKatz’s comment on: Cli­mate Change Is Ne­glected By EA

  The Effective Environmentalism group maintains a document of recommended resources.

• mchr3k 24 May 2020 17:40 UTC

  4 points

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  in reply to: Kirsten’s comment on: Cli­mate Change Is Ne­glected By EA

  Thanks for your comments.

  When I looked at the most recent IPCC report, one of the biggest health impacts listed was an increase in malaria. If we could reduce or eradicate malaria, we could also improve lives under climate change.

  As I mention in my post, the issue with this is that you are fighting an uphill battle to tackle malaria while climate change continues to expand the territory of malaria and other tropical diseases.

  I’d be interested in a direct comparison of some climate donations or careers with some global health donations or careers.

  I have previously written a post titled Review of Climate Cost-Effectiveness Analyses which reviews prior attempts to do this kind of comparison. As I mention in my post above, my conclusion was that it is close to impossible to make this kind of comparison due to the very limited evidence available. However, the best that I think can be said is that action on climate change is likely to be at least as effective as action on global health, and it is plausible that action on climate change is actually more effective.

• mchr3k 24 May 2020 17:33 UTC

  8 points

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  in reply to: HenryStanley’s comment on: Cli­mate Change Is Ne­glected By EA

  Thank you for your comments—I have some responses:

  hundreds of billions of dollars (and likely millions of work-years) are already spent every year on climate change mitigation (research, advocacy, or energy subsidies)

  A huge amount is already spent on global health and development, and yet the EA community is clearly happy to try and find particularly effective global health and development interventions. There are definitely areas within the hugely broad field of climate change action which are genuinely neglected.

  Given the relatively scarce resources we have, both in time and money, it seems like there are places where we could do more good

  This seems pessimistic about the possible size of the EA movement. Maybe if EA didn’t downplay climate change so much, it might attract more people to the movement and hence have a greater total amount of resources to distribute.

Cli­mate Change Is Ne­glected By EA

• mchr3k 5 Nov 2019 19:25 UTC

  1 point

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  in reply to: Denkenberger’s comment on: Re­view of Cli­mate Cost-Effec­tive­ness Analyses

  From your original comment (emphasis added by me to highlight what jumped out at me):

  10°C climate warming over a century would be much lower impact, because there is time to relocate infrastructure and people (and nuclear winter also reduces solar radiation). So I have put it in the intensity category of an abrupt 10% agricultural shortfall.

  From my reply:

  It seems to me like a huge leap of faith is required to believe that the global impact of 10C of warming (over a century) is on the same order of magnitude as an abrupt 10% agricultural shortfall.

  From your reply:

  I agree that 10°C warming over a century would be bad. But would you agree that 8°C cooling and 50% reduction in solar radiation in one year would be worse?

  Also from your reply:

  In this paper, I estimated the expected mortality of an abrupt 10% food shortfall from something like India Pakistan nuclear war was about 500 million. Technically speaking, adaptation and relocation in response to a century long 10°C rise should involve the loss of many fewer lives, but it could go very badly, even up to including full-scale nuclear war, which could kill billions of people. So I think it is in the same order of magnitude in expectation as an abrupt 10% food shortfall. What would your estimate be of the expected mortality a century long 10°C rise?

  It looks like I misread your original comment a bit. When you said “much lower impact”, I didn’t realize that you had predicted 500 million deaths from a 10% agricultural shortfall. I have now read your paper, and am entirely comfortable to agree that: (1) 8°C cooling and 50% reduction in solar radiation in one year would likely be much worse than 10°C warming over a century, (2) expecting ~500 million deaths from a century long 10°C rise seems like roughly the right order of magnitude.

  Having said that, some of the circumstances that would lead to a 10% agricultural shortfall (e.g. extreme weather in several breadbaskets in one year) wouldn’t also come with all the other costs of climate change (mass migration, species extinction etc).

  It is true that humans would not be able to go outside very long without technology. But I would say that is true at 40° latitude in the winter now. It is true that the technology of an insulating coat is fairly simple. But if it is hot, we could use the fairly simple technology of an ice vest like this. More complicated technology could involve a system which burns fuel and then uses absorption chilling to cool the body if one needed to stay cool for many hours. Of course this technology would not be affordable by many people in the tropics now, but 100 years out, I think the situation will be different.

  This may well be true, but this is another case where I’d consider adaption as unacceptable. I don’t want to create a world where we need ice vests, or worse yet—something which needs to burn fuel, to be comfortable outside—particularly when that outcome is entirely avoidable.

  I am concerned about a possible tipping point that would be a runaway greenhouse effect. But since the earth was about 14°C warmer about 50 million years ago, and the sun’s radiation is not that much higher than it was then, I think we only have to start worrying about this at over ~10°C warming.

  I’m worried about tipping points that accelerate and amplify warming much sooner than 10°C of warming. Page 21 of this suggests that anything above 3C is extremely concerning.

  As for prioritizing the present generation, my analysis indicates that prioritizing current global poverty is a couple orders of magnitude more effective than reducing emissions at carbon costs required to solve the whole problem (largely because the current poor will likely be richer when the main climate change impacts hit). However, if you believe the Cool Earth numbers (not counting opportunity costs of the value of the land for farming) and if you don’t think they will be taken by someone else, then it could be competitive. However, I think alternative foods are even better from the present generation perspective.

  As per my comment on HaukeHillebrandt’s comment below—The trouble with these estimates is that I’m not convinced they do a good job of considering how costs change as a technology is scaled. For example, we’ve seen this with solar—http://​​solarsouthwest.co.uk/​​solar-panel-cost/​​. Do you have a recommended source which does somehow take account of these effects? If not, we’re not really comparing costs properly.

  largely because the current poor will likely be richer when the main climate change impacts hit

  Also, I want to specifically comment on this. Unless you believe that very large scale CO2 air-capture is going to be economically/​technologically/​land-use viable, we don’t have time to wait for people to get richer. The CO2 being emitted today, is committing humanity to a particular temperature rise for centuries to come. The cheapest time to deal with that is right now, to avoid putting the CO2 in the atmosphere in the first place.

  I am focusing my analysis on the impact on the long term future, which means the reduction in the long term potential of humanity (out thousands or millions of years).

  [....]

  It is true that this analysis is not taking into account the smaller warmings, but these are less likely to have an impact on the long-term future, so I think they are unlikely to change the order of magnitude of the result.

  [...]

  I don’t think the comparison I am making is Pascal’s Mugging. I think Pascal’s Mugging could be considering the immense potential value of the long-term future and then demanding some sacrifice now. However, since I am looking at the reduction in the long-term future due to climate change and due to nuclear winter, they are on equal footing and do not depend on the precise value of the long-term future.

  In this post I wasn’t trying to look at the long-term value of climate change—I was mostly considering the impacts by 2100. Your response dismisses the concerns about smaller warmings because they are less likely to impact the long term potential of humanity. I still care about these impacts, because they will still kill people in the current century, even if those people don’t matter as much on a long-term basis because human civilization will be fine without them. In my own ethics, I value life which exists today and in the near future more highly than in the far future. The main reason I’m willing to extend my horizon to 2100, is that I have a strong belief that the economic system which I’m living in today will very directly impact people in 2100, so they are not remote and detached from my choices—I bear some responsibility for the world they get to live in. This implies that I use a non-zero discount rate, but which I’m willing to reduce specifically for cases where there’s a strong causal link to actions being taken today.

  At the same time, I rationally understand the argument for long-termism. If I had to pick between (A) a world with terrible climate change, but where human civilization ends up surviving and then thriving for 10 million years, or (B) a world where we avert climate change and then wipe ourselves out in 2110 with a synthetic virus, I would obviously pick (A). But that definitely feels like a mugging—accept climate change because that way some far future people will lead great lives.

  The final thing which makes this all more complex, is that climate change is something which we are on a very well defined trajectory towards—where inaction results in terrible consequences. However, things like nuclear war are risks which may never materialize. If we invest effort into averting credible but potential risks, we’ll never be sure whether that investment actually mattered. If we invest effort in averting climate change, we’ll be much more sure that the effort was worthwhile.

• mchr3k 3 Nov 2019 19:32 UTC

  1 point

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  in reply to: Hauke Hillebrandt’s comment on: Re­view of Cli­mate Cost-Effec­tive­ness Analyses

  Generally, my agenda was probably a bit simpler than people might have supposed. This was not intended to be the last word on whether climate change or development interventions are always better. Rather it’s a starting point and “choose your own adventure” model to help prioritizing between a concrete climate and a concrete development charities. Different situations call for the model to be adapted.

  That may have been your intention, but the title of your article is “Global development interventions are generally more effective than Climate change interventions” and your summary states “My spreadsheet model below shows that climate change interventions are only more effective than global development interventions, if and only if: [...] under quite pessimistic assumptions about climate change (if the social cost of carbon is higher than $1000 per tonne of carbon)”. I think that these things together would make it very easy for a reader to leave with the simple conclusion that climate change interventions are not cost effective, and I just don’t think the evidence exists to back up that simple conclusion.

  I also don’t think that you need to make particularly pessimistic assumptions for the social cost of carbon to be much higher. At the very least, your chosen source of a social cost of carbon used an emission pathway (RCP6.0) which only results in 2.2C of warming by 2100. Based on currently announced national commitments, greenhouse emissions are likely to lead to global temperature increases of 2.3ºC-3.7ºC by 2100 with a 25% chance of exceeding 4°C based on current national policies.

  You write that there are very large flaws in my methodology, but because you then adopted the methodology, I think you actually have quarrels with the empirical estimates that I’ve plugged in, correct?

  I think the methodology is flawed in the sense that you are combining the low/​mid/​high estimates of several parameters to produce an estimate which is 10 orders of magnitude wide. That’s so wide as to be almost meaningless. I produced an updated estimate mainly to demonstrate that it’s possible to produce an estimate where climate change is better value than global health with some fairly plausible choices of parameters.

  However, for large foundations/​governments it doesn’t seem quite as scalable in terms of absorbing very large amounts of money as many global development interventions. That’s why I used an intervention such as ocean alkalinity as an example because it might be a way to absorb large amounts of carbon up to 100 billion tonnes /​ year) for as little as $10 per tonne of CO₂ averted.

  The trouble with these estimates is that I’m not convinced they do a good job of considering how costs change as a technology is scaled. For example, we’ve seen this with solar—http://​​solarsouthwest.co.uk/​​solar-panel-cost/​​. Do you have a recommended source which does somehow take account of these effects? If not, we’re not really comparing costs properly.

  Additionally, it’s worth recognizing that the current economic model has huge climate externalities. I really hope we get a climate emissions tax at some point, at which point the fundamental incentive structures change, and I’m not sure how to properly price emissions reductions at that point. At least from a government perspective, the carbon tax could be considered “free”. Can you recommend any papers which have tried to come up with a cost/​tonne for a carbon tax?

  Finally, can you say a bit more why you prefer the eta, marginal utility of consumption, to be equal to 1? I felt you you did not provide sufficient empirical justification for this.

  Honestly, it’s because I haven’t yet had a chance to read up on the marginal utility of consumption and it seemed implausible to me that the value of money would actually be 3 orders of magnitude higher in a cash transfer situation. I’m very much prepared to believe that I’m wrong, and I hope to find the time at some point to read the research you referenced and figure that out for myself. In my defense, I also think the SCC used in my update is perhaps an order of magnitude too small, so I could also have used a higher SCC and the 1260x income adjustment and come to the same conclusion.

  I hope this did not come across as too critical—I generally really enjoyed reading your treatment and synthesis of the issue.

  Thank you for taking the time to reply! I’ve enjoyed responding to your points :)

• mchr3k 3 Nov 2019 19:04 UTC

  1 point

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  in reply to: Denkenberger’s comment on: Re­view of Cli­mate Cost-Effec­tive­ness Analyses

  Nuclear winter would be approximately 8°C change in only one year, and this is unlikely to cause extinction.

  I don’t actually see a detailed calculation of human impacts in that paper. I agree that full extinction seems unlikely, but hugely catastrophic impacts seem very plausible. Also, a temperature decrease is definitely not guaranteed to have a symmetric impact with a temperature increase, so the comparison doesn’t seem entirely valid.

  10°C climate warming over a century would be much lower impact, because there is time to relocate infrastructure and people (and nuclear winter also reduces solar radiation).

  This is a statement which quickly points out a difference in our ethics. 10C of warming would likely require the evacuation of huge areas of land around the equator. That’s not the same as extinction, but I still consider it to be a deeply unacceptable outcome. Survival alone isn’t good enough for me. I’m not sure how to formalize this viewpoint within utilitarian calculations.

  Also, less abstractly, I’m not confident that the natural ecosystem which we rely on would be able to adapt to 10C in warming over a century. This suggests to me that we would see a huge amount of species being pushed into extinction, and again I consider this to be an extremely negative consequence, even if we are able to figure out ways to feed ourselves from a limited number of crops that we still manage to cultivate.

  So I have put it in the intensity category of an abrupt 10% agricultural shortfall. Based on a survey of GCR researchers, this has a mean long-term reduction in far future potential of approximately 5%.

  It seems to me like a huge leap of faith is required to believe that the global impact of 10C of warming (over a century) is on the same order of magnitude as an abrupt 10% agricultural shortfall. You’d need to lay out much more of an argument for me to believe that. As it stands, I think you are either predicting a much lower impact from climate change than I am, or putting more faith in technological/​economic growth to mitigate the impacts. In either case, it’s clear we disagree.

  This combined with a probability of about 2% gives about a 0.1% reduction in the far future potential. Full scale nuclear war is estimated to have a 17% reduction in long term future potential.

  This only considers the impact of 10C of warming. If we don’t have 10C of warming, we are still going to have an amount less than that. There’s a currently a >25% of >4C of warming, without fully accounting for climate tipping points. 4C of warming is already expected to have serious consequences. However, these haven’t yet been well quantified because even 4C of warming has impacts on so many aspects of the world society, economy, and ecology, that it’s incredibly difficult to model.

  Fortunately, alternative foods also mitigates climate related catastrophes such as abrupt regional climate change, coincident extreme weather on multiple continents, and slow 10°C change (which makes the cost effectiveness of alternative foods even higher than the numbers calculated above).

  This presumes that mitigating climate change through alternative foods is a morally acceptable outcome. As per my statement above, for me, it isn’t.

  But even at a cost of $0.38 per ton CO2, it is still a few orders of magnitude lower cost effectiveness than alternative foods or artificial general intelligence safety from the perspective of the long-term future.

  This statement actually very neatly encapsulates my main objection to long-termism. It feels very much like a case of Pascal’s Mugging. Over a long enough view of the potential future of humanity (e.g. 10s of millions of years), none of today’s problems really matter.

  Can you clarify what exactly you mean by “from the perspective of the long-term future”? What time-horizon do you have in mind, and what kind of discount rate are you applying, if any?

• mchr3k 23 Oct 2019 14:37 UTC

  1 point

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  in reply to: StevenKaas’s comment on: Re­view of Cli­mate Cost-Effec­tive­ness Analyses

  since economists argue over the relative value of mitigation (at least beyond low hanging fruit) and present consumption

  Do you have any particular sources in mind for this? My understanding is that economists are in strong agreement that action now is much cheaper than action in future.

  Re: 1. I think it’s useful to consider concrete examples from history which have killed a large number of people. As per my writeup, in the 20th century, the largest famines killed 10-20M people/​decade, so 1-2M people/​year, all of which happened when the world had fewer than 4 billion people [source]. So if you think that 1-2M people is implausible, then you’re saying that climate change isn’t likely to cause the same kind of agricultural issues as we’ve previously faced, without serious climate issues.

• mchr3k 22 Oct 2019 12:03 UTC

  2 points

  0 ∶ 0

  in reply to: StevenKaas’s comment on: Re­view of Cli­mate Cost-Effec­tive­ness Analyses

  I’m sorry but I don’t follow your argument. I’ll try and explain my own logic and perhaps you can point out the key step where I’m going wrong.

  The 2014 WHO paper provides an estimate for the number of climate attributed deaths in 2030 and 2050. Let’s imagine that these estimates were 30 deaths and 50 deaths. The GWWC approach then assumes a linear relationship between CO2 emissions and deaths, producing a straight line passing through these estimates. So 2030 sees 30 deaths, 2031 sees 31 deaths, 2032 sees 32 deaths etc. The GWWC approach then subtracts the 2030 estimate from the 2050 estimate to give the change per year in the climate attributes deaths. In this toy example, that would be a figure of 1 death /​ year /​ year.

  Now imagine that global emissions drop to zero for a single year in 2030, and that climate response was instantaneous—then we’d expect to see 30 deaths in 2030, 30 deaths in 2031, 31 deaths in 2032, 32 deaths in 2033 etc. So over a 50 year period, we’d see 50 saved lives.

  However, the original GWWC spreadsheet simply takes a fraction of the deaths /​ year /​ year figure, and declares that the resulting total is the number of deaths averted over all time.