I'll just respond to point 3 as it refers to my opinions directly. I don't think one should read me saying "Wow okay" as an off-the-cuff response to something someone says as much evidence that I've changed my mind, let alone that other people should. At that point I haven't had a chance to scrutinise the research, or reflect on its importance.

I suspect I said 'wow okay' because I was surprised by the claimed volatility of food supply in general, not the incremental effect of climate change.

Taking the figures Dave offers at face value, the increase is from 56% to 80% in the remainder of the century, which isn't surprisingly large to me. Not having looked at it, I'd also take such modelling with a pinch of salt, and worry that it exaggerates things in order to support advocacy on the topic.

There was a UK government study on this that estimated right now, it might be around 1% chance per year, but with the slow climate change... They were getting more like 80% chance of this century that something like that would happen.

N.B. (1-0.99^81 = 56%)

Thanks for this. It's useful for the community to think about this kind of thing and this is well-argued.

Overall

1. It's a good point that since the top AI fields seem oversubscribed, it might be worth some people moving into the next best causes. Another possibility is that they should wait until the number of organisations catches up with the number of people. It might even be that the most valuable options is having a reserve of a large number of people who could, with some probability, be a good fit for the highest-impact orgs, even though most of these people never end up working for high-impact orgs. This puts a new slant on the demandingness of EA: rather than making sacrifices by donating, EAs make sacrifices by being prepared to accept the substantial probability of themselves never having impact. This would be hard to take psychologically, but might be the right thing to do in a crowded talent space.

2. On indirect risks, another point I make in the FP report is that while climate change is an indirect stressor of other risks, this suggests to me that working on those terminal risks directly would be a better bet than working on climate change since climate change is such an indirect stressor, is very crowded and seems difficult to make progress on. What do you think of that argument?

ITN

3. I don't think it is right that problems with high tractability should be de-prioritised. I think what you mean is that we should focus on things that shift the long-term trajectory of humanity. But these could be highly tractable. e.g. the problem of not starting nuclear war was tractable for Vasili Arkhipov, but plausibly had large long-term effects. Having looked at it in some depth, climate change does look an intractable problem overall and this is indeed a reason not to work on it.

4. Another good point on how there could be increasing returns to scale in climate change, as we could affect the huge pool of funds going to the space through engagement.

5. Really, the ITN perhaps shouldn't be used when we have cost-effectiveness estimates. On the 80k rendering, ITN is literally a cost-effectiveness estimate. But we now have cost-effectiveness estimates of climate charities. If we can make plausible estimates of the impact of bio, AI and nuclear, then we should use those, rather than appealing to the ITN. similarly, for use of time as well as money.

5. It is premature to say that work on climate change could be tractable. I think careful analysis is needed to figure out whether the things you list are indeed a good bet compared to other things that EAs could do.

Details

6. Climate Action Tracker suggests that on current policy, we are in for 3.1 to 3.5C, which is different to the 'baseline' trajectory estimate that you give. I think the current policy trajectory is most relevant for that part of your argument. (But note that this is only by 2100)

7. The impact of climate change on food production is in fact predicted to be fairly modest, as I discuss here. Yields might fall by 10-20% but this will be in the context of rising productivity and improvement in the other factors that determine the supply of food.

8. The emphasis on water shortage throughout is a bit overblown. We don't need to ration water, we just need to price it properly (which is efficient rationing). If we did that, there would be no water problems today or in the future, anywhere (provided people had enough money).

While climate change doesn't immediately appear to be neglected, it seems possible that many people/orgs "working on climate change" aren't doing so particularly effectively.

Historically, it seems like the environmental movement has an extremely poor track record at applying an "optimizing mindset" to problems and has tended to advocate solutions based on mood affiliation rather than reasoning about efficiency. A recent example would be the reactions to the California drought which blame almost anyone except the actual biggest problem (agriculture).

Of course, I have no idea how much this consideration increases the "effective neglectedness" of climate change. I expect that there are still enough people applying an optimizing mindset to make it reasonably non-neglected, but maybe only par with global health rather than massively less neglected like you might guess from news coverage?

This source suggests we’re on for 4.1-4.8C of warming by 2100, so it seems erroneous to assume 2-4C should be our baseline assumption.

It's hard to tell where this site is getting its numbers from, but my understanding is such claims are usually based on misrepresenting the RCP 8.5 emissions scenario as representative of business as usual even though it makes a number of pessimistic assumptions about other uncertainties and is widely considered as more like a worst case scenario than a median case scenario.

As far as I can tell, claims that extremely high climate sensitivities are plausible tend to be based on conceptual misunderstandings of Bayesian probability.

The Stern Review isn't representative of climate economics as a whole and has various problems that you can find using your favorite web search engine.

I'd like to make a few points based on my knowledge as someone who studies climate science issues as a hobby. I'm a member of the volunteer team at SkepticalScience (an anti-climate-misinformation site).

[edits/additions in square brackets; original version contained mistakes]

First, humanity needs to reduce carbon emissions all the way to zero or below, because natural removal of CO2 from the climate system is extraordinarily slow. 50% is too much; 25% is too much. Zero. Popularly-considered strategies for mitigating global warming won't achieve that. Optimistic IPCC scenarios like like RCP 2.6 assume technology will also be widely deployed to remove CO2 from the air. Things like tree planting that increase biomass can slow down the increase of CO2 but can't stop it even briefly; other ideas for carbon sequestration are not economical [AFAIK] and it's irresponsible to simply assume an economical technology for this will be invented. Therefore, we need to switch to 100% clean energy, and do so as soon as possible.

In my opinion the best thing the EA community can do (under the importance-tractability-neglectedness framework) is to study and support nuclear energy in some affordable way. In the past, the push for climate change mitigation has come from traditional environmentalists, who have fought against nuclear power since at least the early 1980s [probably more like 1960s] and mostly haven't reconsidered. This is evident from the many campaigns for "renewable energy" rather than "clean" or even "sustainable" energy. EA can fill a gap here. My favorite thing is to ask people to support new, inexpensive Molten Salt Reactor (MSR) designs. But probably the cheapest thing we can do is a web site. I think there is a real need for a web site about nuclear facts (or clean energy facts generally), something that debunks myths like SkepticalScience does for climate science, and also provides information that isn't adequately available on the web right now, about such topics as the risks of radiation, the types and quantities of nuclear waste, and the ways nuclear regulations have improved safety (albeit increasing costs). And, of course, it would go into some detail about MSRs and other affordable next-generation reactor designs. As EAs are not funded by the nuclear industry, they could be a credible independent voice.

Solar power makes great sense in a lot of tropical places, but in northern climates like Canada it doesn't, as peak energy use happens in the wintertime when the sun is very weak. AFAICT this makes solar in Canada into a nuisance, a potential roadblock as we get close to 100% clean energy (why would we deploy more clean energy if existing solar power makes it redundant for half of each year?). Without nuclear power, our main source of energy [in such climates] would probably have to be wind, and I'm very concerned that the cost of relying mostly on wind power would be prohibitive, especially in a free-market system. I don't know the exact numbers, but once we exceed something like 25%-30% average wind power, instantaneous wind power will often exceed 100% of demand, after which wind turbines are likely to become less and less economical. (Epistemic status: educated guess [but after I posted this someone pointed me to a presentation by an expert, which says solar value starts to decline well before 25-30% penetration])

[Meanwhile, right now nuclear advocates often rely on bare assertions, some of which are wrong. Without credible-but-readable sources - plain language explanations that cite textbooks, scientific literature and government reports - it's hard to convince intellectuals and reasonable skeptics to change their mind. Anti-nukes can simply assert that claims that make nuclear power look not-scary are nuclear-industry propaganda. Note that nuclear power relies on public opinion much more than renewables currently do - company are free to design and build new wind turbines, but nuclear power is, of necessity, highly regulated and its continued existence relies on political will, which in turn flows from popular opinion. Witness the blanket shutdown of all nuclear power in Germany based on the effects of a tsunami on Fukushima, Japan. Hence the motivation for an educational site.]

By contrast, it seems clear to me that mass-produced MSRs can [theoretically] be cheaper than today's CCGTs (natural gas plants). I've been following MSRs with great interest and I've published an article about it on medium, although it remains unlisted because I'm still uncertain about a couple of points in the article and I'd love to get a nuclear expert to review it.

Second, it is a common misconception that we could have 4°C of global warming by 2100; climate scientists generally don't think so [except in the RCP 8.5 (business as usual) scenario which by now is more of a "look at the train wreck we're avoiding!" than a plausible outcome]. Often this misconception arises because there are two measurements of the warming effect of CO2, and the most commonly reported measure is ECS (equilibrium climate sensitivity) which predicts the amount of warming caused by doubling CO2 levels and then waiting for the climate system to adjust. The best estimate of ECS is 3°C (2.0-4.5°C, 90% confidence interval according to the IPCC) and it will take at least 200 years after CO2 doubles to even approach that amount of warming. If the ECS is higher than 3°C I would expect it to take even longer to approach equilibrium, but I'm rather uncertain about that.

To estimate the warming we expect by 2100, look at the TCR (Transient Climate Response) instead. The TCR is highly likely to be in the range 1.0-2.5°C. Keep in mind, however, that only 2/3 of greenhouse warming comes from CO2 according to the AGGI; 1/6 comes from methane and the final 1/6 from all other human-added greenhouse gases combined. The most common estimate of TCR is 1.7°C or 1.8°C and a first-order estimate based on observed warming so far is about 1.5°C. So if CO2 doubles (to 560 ppm), I'd expect about 2.5[±1.1]°C of global warming based on a TCR of 1.75, assuming CO2's fraction of all GHGs increases slightly by then. [side note: I would be surprised if CO2 more than doubles - I think we'll get almost 100% clean energy by 2100; OTOH predicting the future isn't really my forte.]

Third, Having said that, the land will warm a lot faster than the oceans. Climate models on average predict 55% more warming on land than sea [related paper]. [Observations so far suggest that the transient difference could be] greater. Therefore, although 4°C of "global" warming by 2100 is highly unlikely, 4°C of land warming by 2100 is a distinct possibility (though I estimate a probability below 50%.)

I guessed on Metaculus that global warming by 2100 would be [1.7 to 2.6°C] (despite the Paris agreement), but on land [it's likely to reach 3°C (and as climate change is non-uniform, some populated locations could exceed 3°C even if the land average is less than 3. I should add that the land-sea ratio is thought to be lower in the tropics, albeit higher in the subtropics. And my prediction was somewhat optimistic—I assumed that eventually society would build nuclear plants at scale; or that at least some cheap CCS tech would be discovered.)]

Fourth, having lived in the northern Philippines, I think the impact of the warming itself is underappreciated. I lived in a very humid town (more humid and hotter than Hawaii) where the temperature exceeded 30°C in the shade most days. The hottest day of the year was about 37°C in the shade at noon, coldest would have been around 18°C at 6AM.

Maybe it's just that I lived in Canada too long, but humans are humans - we are naturally uncomfortable if our core temperature exceeds 37°C and I became uncomfortable whenever I went outside or left the sanctuary of the Air Conditioner. So for the sake of Filipinos and the other 3+ billion people living in tropical latitudes, I think we should be very concerned about the effect of just the warming itself on humanity's quality of life.

If we get 4°C of [land] warming vs preindustrial, that implies average daily highs of about 33-34°C in my town, which I would describe as virtually unbearable at 75% humidity. Consider also that if the Philippines becomes more prosperous, they will respond to the high temperatures by extensive use of air conditioning, which is energy intensive. If we don't stop using fossil fuels soon, air conditioning itself can become a significant contributor to further global warming.

I worry that EA is over-focusing on things we can fix relatively easily, like disease and farmed animal welfare, at the detriment of things that could alter the trajectory of our civilisation.

At a few points in this post, you argue for climate change possibly being more important to tackle than the major short-termist causes within EA. Do you also see it as something which should redirect resources currently being spent on long-termist causes? It's odd to see a claim that EA doesn't focus enough on "things that could alter the trajectory of our civilization" when most popular critiques of EA say the opposite (too much focus on long-term risks, not enough on helping people in clear/direct ways).

On the other hand, one benefit of comparing climate change to disease/animal welfare is that the donor demographics for climate change may be more similar to the demographics for disease/animal donors than for donors to other X-risks (e.g. people with an environmentalist bent, people interested in the Global South).

This intellectual heritage and the focus on short-term numbers and results influenced by the short-term world of hedge funds, and this approach could be at the detriment of missing out on broader changes.

This is a small nitpick, but I don't think I've ever seen the claim substantiated that EA's focus has been unduly influenced by "the short-term world of hedge funds", even though people make it all the time. Yes, GiveWell was founded by hedge-fund veterans, but the tools they borrowed from Bridgewater were (as far as I know) related to EV calculations, not "having a short time horizon". EA has, almost since the beginning, had a stronger focus on the long-term future than nearly any other social movement.

I'm not nearly as smart or involved as many people in this community, but quickly after discovering EA (about 4 years ago) I got the impression that climate change and threats to biodiversity were underestimated, and was surprised at how little research and discussion there seems to be.

One point I would like to raise is that this community seems to assume that everyone starts (or should start) from the assumption that human life and our species's continued existence is valued above all else. It's very anthropocentric, which is another thing that may alienate potential effective altruists (like myself).

Personally, I value biodiversity for its own sake, as well as its benefit to humans, since I come from a long-term ecologists' perspective (put simply, I value the continuance of life rather than focusing on one species, and a more diverse biosphere/ecosystem is a healthier and more resilient one). I believe there should be a balance between ecologist and humanist efforts.

I wonder if part of this bias toward humanist efforts is because it's much cleaner and easier to measure costs and benefits in terms of human lives/DALY etc., since there are more data and research done.

Anyway, I would be curious to hear EA's perspective. And if there are convincing reasons I should reprioritize my values, I am open to changing my mind.

This is an interesting post by Ramez Naam. He argues that too much attention is given to transportation & energy emissions and not enough to agriculture & industry emissions. Naam thinks that renewable tech will continue to drop in cost, and he's optimistic that part of the equation will solve itself. He says the highest-leverage action is the development of new tech to address agriculture & industry emissions.

I would like to offer a simple personal note that my focus and energy has turned away from EA to climate change only. I now spend all of my time and energy on climate related matters. Though I still value EA's approach to charity giving, it has begun to feel like a voice from the past, from a world that no longer exists. This is how it registers with me now.

Thanks for your hard work in writing this. I was impressed by the depth of thought and how well it was linked to other articles.

1.

I agree climate change is not an x-risk, and though EA shouldn't focus on it, we should probably discuss it a bit more and bring our critical thinking to help solve the problem more efficiently. Not discussing it seems like at best an oversight, and at worst, harmful.

This seems like a wise comment. We should all be open to criticism, particularly if we are disagreeing or taking a nuanced view on something the majority of people think is really important or that they expect us to care about.

2. Overall, it seems reasonable to me that EA resources might be ill spent in working on climate change, since there is already so much money and so many people going to work there. Several of my non-EA friends are deciding to fight climate change of their own accord. I think it would be better if they used an EA methodology and it would be better if the people at the top of anti-climate change orgs used this methodology but it seems much of what you speak of is answered by the fact that additional EA members in that community may not (or may) do much additional good compared to their intervention elsewhere. I don't know how to judge that.

Perhaps in regard to this, it would be better if rather than getting jobs in these spheres EA people were encouraged to vote wisely, donate wisely, engage with their communities, be informed about climate change. Maybe this is what you had in mind anyway.

Another consideration comes to mind: climate change is currently taking up a large amount of attention from competent altruistic people. If the issue were to be solved or its urgency reduced, some of those resources might flow into EA causes.

Thanks all for your comments. A few friends have emailed me and made a couple of points about this post.

1. On the first-order effects of warming, the Stern Review figures are now 10 years out of date, and the IPCC SR1.5C expects worse impacts to welfare than previously stated, under all trajectories. See Chapter 5 of the report, and Byers et al. 2018.

2. A good source on the impact on GDP and societies through sea level rise is Pretis et al. (2018, Philosophical Transactions of the Royal Society)

3. The goal for climate change mitigation should be getting to net zero emissions as fast as possible, as anything other than that still causes warming, and this goal is absent from many EA and the 80,000 Hours write-up.

4. Absent from these discussions are climate economists, who would be able to help us grapple with this more concretely. Some suggested economists to research (and for the 80,000 Hours Podcast) are Adair Turner, Simon Dietz, Cameron Hepburn, and Joeri Rogelj.

Great read, although I think there are a couple of points, some already mentioned, that are worth highlighting further:

With regards details:

I would agree that the Stern report is now pretty old hat, it's over a decade old and there has been plenty of work since then, both on the climate science side (e.g. the discussions below on TCR vs. ECS) and on the economics side (e.g. what discount rate and damage function to use to work out impacts on global GDP).

I'd also say that it is remiss to leave out the IPCC's latest report on 1.5 degrees, given that it includes all of the most recent literature (and also given that it took on board a fair bit of previous criticisms of IPCC reports, regarding presentation of data, discussion of probabilities etc.).

Beyond this, I would go further and say that, to be honest, discussions about tail-risks of 6 degrees of warming, based off of uncertainties in ECS or TCR values, are of second-order importance. I think you can make a very convincing case for acting on climate change simply based off of the evidence presented in the IPCC SR1.5:

I checked some numbers, in order to illustrate the point about judging the impacts climate change. (The specific paper cited in the SR1.5 that is relevant for this is Byers et al., 2018)

Chapter 5 of the report cites a range of 62-457m fewer people that are 'exposed and vulnerable' at 1.5 versus 2 degrees of warming, based on three contrasting pathways out to 2100 (i.e. exposed to multi-sector climate risks and vulnerable to poverty, defined as income <10$/day).

Given the IPCC only backs these findings with 'middle confidence', if we take the lower range then we have ~62m fewer people exposed and vulnerable, at 1.5 degrees. If we spread that out over the 80 years out to 2100, it's about 800,000 people each year who are either vulnerable to poverty or susceptible to various risks. That's roughly twice as many people as die from malaria each year, one of the highest-priority sectors for GWWC. Obviously, the people affected by climate change aren't dying each year, but they are more susceptible to poverty, in worse living conditions, higher risk of extreme weather events etc. If we work on basis of reducing suffering then surely, even just the fact that, right now, you have comparable numbers of people being affected, should somehow be discussed and taken into account far more.

This is just one example, from one paper cited in the report - there are obviously far more, adressing a very broad variety of impacts. Another great reference is a paper by Pretis et al. (2018, Philosophical Transactions of the Royal Society) that highlights both the aggregate impacts on global GDP and the significant geographical disparities in the impacts on economic growth: the largest relative impact of 2C vs. 1.5C is on people on lower incomes in South-East Asia and Sub-Saharan Africa, predominantly living in coastal areas. This has been discussed in other comments as well, but I think that this specific paper is excellent.

In my opinion, there is little need to go into discussions about climate sensitivity, or tail-risks of 9 degrees, to make a strong case for weighting climate change more highly.

There is also the point about the adequacy of the ITN framework and the inclusion of 'urgency', which I think is a great one:

Beyond just the urgency of the problem with regards timescales of action, there is also the totality of the issue, as discussed in John's summary report and mentioned below - we have to get to net-zero, you can't just reduce GHG emissions by 50, 90 or even 99%.

This is a point that doesn't get discussed enough (beyond the fact that, for example, the report page on 80000 hours is mad old and out of date). Contrast this with, say, improving international discussions about nuclear disarmament, which could reduce the associated overall x-risk by 50% - a 50% reduction in GHG emissions will never be enough, because we'll still be warming things up. So, even though the marginal impact of a few keen EA people working on nuclear war, biohazards or AI might be very high, this neglects the fact that when it comes to climate change, the reductions have to be total, and we can't settle for less.

I think that this should also be taken into account in terms of 'urgency', or maybe it could somehow be factored into another part of the ITN framework. As you discuss in the post, I highly doubt that climate change is an x-risk, but I feel like this isn't really even the point: it doesn't need to be, nor does it even need to be a 'multiplier', in order to be taken seriously.

Your point about the bias towards intellectually stimulating problems is also fair, I think - there are always people who love to be 'bearish' and predict doom, but I think it is a bit of a form of escapism to choose to focus on other issues. I think there might be something in the fact that it is, frankly, fairly tedious work on continuous international discussions, the minutiae of national-level policies or working out how to influence financial flows for infrastructure. Still, I think this point was a really good one, and unfortunately one that a lot of people likely need to hear.

These last two points together, I think, tie in with what you said about the tractability of climate change: it is reasonably tractable, which probably makes it less sexy to work on, which means that EA people avoid it, and also means that we will never achieve the goal of totally reducing GHG emissions to net-zero.

Finally, I really do think that featuring interviews with a few prominent climate scientists or economists should be a big priority, as you could easily thrash out any misconceptions, worries or misunderstandings on either front - there are loads based in Oxford or London, where lots of UK EA people are. For the science, people like: Myles Allen, Friederike Otto, Sir Brian Hoskins, Joeri Rogelj, Tim Palmer (mentioned in John's report). For the economics: Cameron Hepburn, Simon Dietz, Joeri Rogelj again. Just get them on Rob's podcast, and clear this stuff up!

Thanks for the article, and for the great discussion it has already prompted, as seen in the comments.

Some of this reasoning about social impacts, nonzero probability of severe collapse, dynamic effects, etc, applies equally well to many other issues. Your comment on S-risks - you could tell a similar story for just about any cause area. And everyone has their own opinion on what kind of biases EAs have. So a basic GDP-loss estimate is not a very bad way to approach things for comparative purposes. You are right though that the expected costs are a lot more than 2% or something tiny like that.

In Candidate Scoring System I gave rough weights to political issues on the basis of long run impact from ideal US federal policy. I expected the global GDP costs of future GHG emissions at 26% by 2090, and used that to give climate change a weight of 2.9. Compare to animal farming (15.6), existential risks from emerging technologies (15), immigration (9), zoning policy (1.5), and nuclear security (1.2).

Whether climate adaptation could also be potentially high value for EAs

For the same game theoretic reasons that make climate change a problem in the first place, I would expect polities to put too much emphasis on adaptation as opposed to prevention.

Thanks for this post. Appreciate the "empirical ideas about tackling climate change" but also found the concepts of climate change multiplying very bad outcomes useful.

I wanted to pick up on the "urgency" idea. Doesn't urgency just mean that there are more ways in which it is important, because it has an interactive effect with other issues? I.e. considering urgency means that the importance/scale is high now, even if it might not be as high in the future?

Happy to be challenged on this; I use the ITN framework a lot (I'm sure we all do), so substantial criticism of that model seems worth delving into.

A recent study using machine learning assisted simulations could change the risk assessment for extreme scenarios of climate change. Fortunately the possible tipping point is estimated at the very high point of 1200ppm CO2.

https://phys.org/news/2019-02-high-co2-destabilize-marine-layer.html

https://climatenewsnetwork.net/carbon-rise-could-cause-cloud-tipping-point/?fbclid=IwAR3IF-GemzXGXzsLyq62FI2HUmvFfzpsaUyq1ET3PvU-gu-8Atr01iSCRVM

Yes, absolutely...the 80K podcast occasionally pays it lip service by saying "we agree with the scientific consensus", but it doesn't seem to go much further than that