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.

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.

Our overall view

Sometimes recommended
This is a pressing problem to work on, but you may be able to have an even bigger impact by working on something else.

Scale  

14 / 16

Extreme climate change could have catastrophic consequences for human civilisation. Also see ‘Explanation of how we scored this problem’ below. 1

Neglectedness  

2 / 12

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 / 8

Coordination is difficult due to the free-rider problem. However some options such as efficiency are straightforward.

Profile depth

Exploratory 

Profile author

Roman Duda

This is one of many profiles we've written to help people find the most pressing problems they can solve with their careers. Learn more about how we compare different problems, see how we try to score them numerically, and see how this problem compares to the others we've considered so far.

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:

Screen Shot 2016-04-15 at 12.33.19 AM

Image source.

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 and you might think that this problem is already receiving quite a lot of resources.11
  • 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:

  1. 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.
  2. 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?

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

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Notes and references

  1. The risk of extreme climate change (>5ºC) in the next 100 years is 0.5-10%; it would reduce the future potential of humanity by ~20% through a risk of extinction, worse values, international conflict or social breakdown and a failure to recover. With a major effort at the problem, this risk could be reduced by a further 50%. This estimate is necessarily highly uncertain.
  2. 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 under $10-100 billion per year, because much of this spending is not focused on the extreme risks of climate change or poorly spent.
  3. Coordination is difficult due to the free-rider problem.
  4. The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report considers a global average temperature increase of 2.6-4.8ºC by 2100 to be "likely" under a high emissions scenario. See table 2.2 https://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FINAL_full_wcover.pdf
  5. For an overview, see http://www.givewell.org/shallow/climate-change/impacts.
  6. “The increase of global mean surface temperature by the end of the 21st century (2081–2100) relative to 1986–2005 is likely to be 0.3°C to 1.7°C under RCP2.6, 1.1°C to 2.6°C under RCP4.5, 1.4°C to 3.1°C under RCP6.0 and 2.6°C to 4.8°C under RCP8.5” “The following terms have been used to indicate the assessed likelihood of an outcome or a result: virtually certain 99–100% probability, very likely 90–100%, likely 66–100%, about as likely as not 33–66%, unlikely 0–33%, very unlikely 0–10%, exceptionally unlikely 0–1%.” Given that the “likely” range is taken to cover 66-100% of the probability of temperature changes, we might expect that roughly 17% of the probability distribution lies outside the 2.6-4.8°C range. Given that the distribution is right skewed, we would expect 10% or more to fall on a change greater than 4.8°C.” Source.
  7. About $11 million is spent per year on Geoengineering research. “Our total tally of funding for such projects (for which we have funding information) amounts to about $11 million/year.” Source
  8. “...U.S. federal government reports seem to indicate that they spend roughly $8 billion a year on climate change efforts, mostly (~$6 billion/year) on developing technology to reduce emissions.” Open Philanthropy Project: Antropogenic Climate Change
  9. “The Government will maintain its effort on urgent action to tackle climate change by supporting low-carbon growth and adaptation in developing countries. The UK’s pool of money for climate change projects in developing countries will be increased to £969 million, funded by DFID, the Department of Energy and Climate Change (DECC) and the Department for Environment, Food and Rural Affairs (DEFRA).” HM Treasury: Spending Round 2013
    Archive
  10. “Based on these reports and an off-the-record conversation, we would estimate that typical annual philanthropic spending on climate change mitigation in the U.S. is likely in the range of a few hundred million dollars.” Open Philanthropy Project: Antropogenic Climate Change
  11. “Reductions in greenhouse gas emissions are expected to disproportionately reduce the risk of extreme temperature increases and extreme impacts (relative to how much they reduce median estimated temperature changes), so mainstream interventions to reduce the negative impacts of climate change in general (discussed on our page on anthropogenic climate change) may be the most effective strategy for addressing extreme risks” http://www.givewell.org/shallow/climate-change/extreme-risks
  12. Source
  13. “Reductions in greenhouse gas emissions are expected to disproportionately reduce the risk of extreme temperature increases and extreme impacts (relative to how much they reduce median estimated temperature changes), so mainstream interventions to reduce the negative impacts of climate change in general (discussed on our page on anthropogenic climate change) may be the most effective strategy for addressing extreme risks” http://www.givewell.org/shallow/climate-change/extreme-risks