To better understand the consequences of climate change over the short, medium, and long term, the Forethought Foundation turned to Good Judgment to forecast how rising global temperatures will impact critical issues like drought, floods, food availability, and severe weather events.

For this project, which was launched in conjunction with William MacAskill’s new book, What We Owe The Future, the Superforecasters were asked to weigh in on 22 questions related to the long-term risk of climate change, making predictions on topics such as future levels of CO2 emissions, the future of the Amazon biome, the cost of solar energy, and the risk of human extinction.

Below are some featured observations based on the Superforecasters’ commentary. You can read the full report here.

Key findings:

• When it comes to political will, Superforecasters are a pessimistic bunch. In general, they do not forecast that politicians, and often the general public, will be willing to make the hard choices needed to mitigate the drivers of climate change.
  • In the short term, people in most of the world will continue to exploit cheaper (but dirtier) sources of energy, according to the Superforecasters.
  • By 2100, according to the median forecast, nearly 30% of the current Amazon biome will transition to savannah.
  • Drivers, ranchers, and homeowners will all demand what is least expensive in the short term and ignore the longer-term impacts. Politicians will bend to those demands.
• When it comes to human adaptability, Superforecasters are more optimistic. They forecast that droughts, floods, and hot weather will all increase, but on timescales that allow humans to adapt.
  • Populations will move away from flood zones and inhospitable regions. This resettlement will involve an immense amount of displacement and suffering in many cases.
  • Urban areas at sea level will be hardened against flooding.
  • Agricultural practices will change in each given locale, but so will the science and technology of agriculture; in fact, crop yields are forecast to increase over all timeframes. Despite this likely total increase, some people will inevitably end up worse off as a result of climate change. Minimizing harm from this agricultural transition will be a key moral consideration facing scientists, technologists, and policymakers.
  • Technological advances will make renewable energy cheaper and more reliable, helping the world get closer to its CO2 emissions targets.
• As for the possibility of human extinction by 2100 or 2300, almost all Superforecasters agree that catastrophic impacts are quite possible, but not existential ones. While most don't see pathways to the total elimination of the species, they do see the potential of great future harm and even the chance of billions of deaths from climate change. These harms are likely to fall disproportionately on disadvantaged people in low-income countries. We have a clear moral responsibility to not impose these harms and to make concerted efforts to reduce emissions.
  • The Superforecasters assign a 1% probability on aggregate that climate change will be a necessary, but not necessarily sufficient, cause of human extinction by 2100.
  • Some Superforecasters argue that by 2100 we will likely be a multi-planet species.
  • Among the scenarios they considered, conflict in its various forms represents a prominent risk, as well as a “tipping cascade,” or a cascade of adverse climate effects.

After the Superforecasters provided their initial forecasts, ten subject matter experts examined the initial forecasts and provided feedback and additional sources, after which the Superforecasters had the opportunity to consider and react to the expert feedback. We are grateful for the contributions from Matthew Burgess, Matthew Ives, Linus Blomqvist, Katrin Burkart, Patrick Kinney, Kieran Hunt, Ertug Ercin, Benjamin I Cook, Chris A Boulton, and Andrew Watson.

You can read the full report here. 

If you want to forecast these topics yourselves, you can forecast in Good Judgment Open here.