Note: This is one of many ‘problem profiles’ we’ve written to help people find the most pressing problems they can contribute to solving, and thereby have a larger social impact. Learn more about how we compare different problems, see how we try to score them numerically, and check the list of all problems we’ve considered so far.
Summary
According to current estimates, unmitigated greenhouse emissions are likely to lead to global temperature increases of 2.6ºC to 4.8ºC by 2100. If this happened, there’d likely be significant humanitarian harms, including more severe weather, food crises, and the spread of infectious diseases which would disproportionately affect the world’s worst off.
But there is a non-negligible chance that unmitigated emissions will lead to even larger increases in global temperatures, the results of which could be catastrophic for life in Earth. Though the chance of such large increases is relatively low, the degree of harm that would result is very high, meaning that the expected value of working to reduce these extreme risks may also be very high.
You are more likely to think that extreme climate change is among the most pressing global problems if you think that we have obligations to people who do not yet exist and that there is great value in ensuring that human civilization continues in the long term.
How to contribute to this problem
Options for working on this problem include academic research into the extreme risks of climate change or whether they might be mitigated by geoengineering. One can also advocate for reduced greenhouse emissions through careers in politics, think-tanks or journalism, and work on developing lower emissions technologies as an engineer or scientist.
| Factor | Score (using our rubric) | Notes |
|---|---|---|
| Scale | 13 | Extreme climate change could have catastrophic consequences for human civilisation. Also see 'Explanation of how we scored this problem' below.1 |
| Neglectedness | 3 | The resources dedicated to preventing climate change globally, including both inside and outside all governments, is probably $100-1,000 billion per year. However, we are downgrading that to an effective $10-100 billion per year, because much of this spending i) would have happened for other reasons, ii) is not focused on the extreme risks of climate change iii) is poorly allocated.2 |
| Solvability | 4 | Coordination is difficult due to the free-rider problem. However some options such as efficiency are straightforward. |
| Recommendation | Recommended - second tier | This is a pressing problem to work on, but not among the very most pressing. |
| Level of depth | Exploratory profile | We’ve made an initial evaluation of this problem by summarising existing research. |
What is this problem and how much does it matter?
What is our analysis based on?
We mainly drew on the Open Philanthropy Project’s reports on anthropogenic climate change, extreme risks from climate change and geoengineering research.
What is this problem and what are the arguments for working on it?
According to current estimates, unmitigated greenhouse emissions are likely to lead to global temperature increases of 2.6ºC-4.8ºC by 2100.4 If this happened, there’d likely be significant humanitarian harms, including more severe weather, food crises, and the spread of infectious diseases which would disproportionately affect the world’s worst off.5
But there is also a non-negligible chance — perhaps around 10% — that unmitigated emissions will lead to global temperature increases even higher than 4.8ºC.6 More generally, estimates of temperature increases resulting from greenhouse emissions have a “fat” right tail, meaning that there is a low, but non-negligible chance of very high temperature increases:
What’s worse, expected harms from temperature changes get worse with each increase in temperature — going from 3ºC to 4ºC is expected to be significantly worse than going from 1ºC to 2ºC. If temperature gains exceed 4.8ºC this would likely have catastrophic consequences. Read more.
In sum, there appears to be an uncomfortable probability — small, but non-negligible — of seriously bad outcomes resulting from unmitigated greenhouse emissions. We call these the extreme risks from climate change.
Arguments for working on this problem
- Though the chance of catastrophic outcomes is relatively low, the degree of harm that would result from large temperature increases is very high, meaning that the expected value of working on this problem may also be very high.
- Although climate change as a whole gets a lot of attention, only a small part focuses on research into the likelihood of the extreme risks of climate change, and on research into the feasibility, likely side-effects and risks of geoengineering (large-scale interventions in the Earth’s climatic system with the aim of limiting climate change).7
What are the major arguments against working on it?
- Somewhat crowded – Climate change as a whole gets a lot of attention and funding already. The US government spends about $8 billion per year on direct climate change efforts8 and more on regulations designed to limit carbon emissions. The UK spends about £1 billion per year on climate change projects in developing countries9 and several hundred million dollars are spent each year by foundations.10 On top of this many businesses and universities around the world work on general climate change research or technologies designed to reduce emissions. The Climate Policy Initiative counted almost $400b in climate change related spending in 2015. Although only a small amount of this effort focuses on the extreme risks from climate change, reductions in greenhouse emissions disproportionately reduce the risk of extreme temperature increases. Therefore most of the existing funding directed at climate change is going to a quite reasonable strategy for working on the extreme risks from climate change.11 Therefore, you might think that this problem is already receiving quite a lot of resources.
- Difficult to make progress – Mitigating climate change is especially difficult because much of the costs of greenhouse emissions are borne by other countries and by future generations. The international dimension creates a free-rider problem between countries – it is in each country’s interest to bear less of the costs of climate change mitigation, which makes international coordination on policies difficult. The intergenerational dimension is perhaps even more problematic — the worst consequences of climate change are remote, decades or centuries out, leaving little incentive for us to act now to prevent these distant effects. Given these difficulties, you might expect efforts to reduce climate change to have little payoff. Consistent with that, many countries have failed to meet their stated commitments to reduce carbon emissions.12
Key judgement calls you need to make
You are more likely to think that this is among the most pressing global problems, if:
- You think that we have obligations to people who do not yet exist (in addition to people who currently exist).
- You think that there is great value in ensuring that human civilization continues in the long term.
- You think there is great value to preserving the Earth’s ecosystems and biodioversity.
- You are comfortable with pursuing high-risk, high-reward methods for improving the world, such as social advocacy, lobbying governments, and speculative research.
- You are comfortable with working on highly uncertain problems – where you are reducing the chance of low-probability, very bad outcomes.
What can you do about this problem?
What approaches exist for solving this problem?
- Reducing greenhouse gas emissions. Reductions in greenhouse emissions disproportionately reduce the risk of extreme temperature increases relative to median temperature increases, and so approaches for working on climate change in general may be the most effective way to reduce the extreme risks from climate change.13 Approaches to reduce emissions include:
- Lobbying governments to introduce policies to reduce greenhouse gas emissions, for example through a carbon tax or quota system;
- Developing lower emissions technology (e.g. cheaper solar panels);
- Reforestation and preventing deforestation (for example the work of Cool Earth).
The Open Philanthropy Project also identifies the following two approaches focussed on extreme risks specifically:
- Research into geoengineering. Geoengineering refers to large-scale interventions in the Earth’s climatic system with the aim of limiting climate change. Geoengineering may become more attractive to governments in the future if large temperature increases occur. Research we do now about its feasibility, likely side-effects, risks and optimal governance could help future policymakers make more informed decisions about whether to use geoengineering when facing extreme climate change. However, continued investment in geoengineering research may also cause less investment in other mitigation and adaptation strategies. See GiveWell’s page on geoengineering research for more.
- Further research on extreme climate change. Research could better inform policymakers about the likelihood of the extreme risks of climate change, and strategies to reduce these risks.
What skill sets and resources are most needed?
- Researchers with expertise in climate science or how to coordinate countries to reduce emissions.
- Engineers who can develop new clean technology and alternative energy sources.
- Policymakers, activists and lobbyists who can push through policies to reduce greenhouse gas emissions.
Who is already working on this problem?
- There are many organisations working on climate change in general. A notable foundation working on encouraging government adoption of mitigation policies is ClimateWorks. Cool Earth was identified by Giving What We Can’s research as a promising organisation working on preventing deforestation.
- Research on extreme climate change occurs mainly in academia and is funded by basic science funders like the US National Science Foundation. The Centre for the Study of Existential Risk at the University of Cambridge and Global Catastrophic Risk Institute are conducting research into extreme climate change and possible responses.
- Geoengineering research also mainly done in academia. The Oxford University Geoengineering Programme conducts research into the social, ethical and technical aspects of geoengineering. The Solar Radiation Management Governance Initiative works on developing safe governance of the most prominent form of geoengineering.
What can you concretely do to help?
- Do a PhD in climate science and do research into extreme climate change in academia.
- Do graduate study in Economics or Public Policy and do research into policy-related solutions to extreme climate change.
- Donate to or work at Cool Earth.
- Work at ClimateWorks, or other foundations focused on climate change.
- Get into positions where you can advocate for climate change mitigation policies and legislation, for example by going into national politics, journalism or think-tanks.
- If you’re an engineer or scientist, work in R&D for developing lower emissions technology. See some suggestions for how to do that here.
Learn more
- Climate Shock: The Economic Consequences of a Hotter Planet by Environmental Defense Fund senior economist Gernot Wagner and Harvard economist Martin Weitzman
- Summary of Climate Shock
- Podcast with the author, Martin Weitzman
- Global Catastrophic Risks chapter 13 on climate change
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