Asteroids are small, rocky objects that orbit the Sun. Depending on their size, asteroids with the potential to collide with planet Earth could pose a global catastrophic risk or even an existential risk.


In The Precipice: Existential Risk and the Future of Humanity, Toby Ord offers several policy and research recommendations for handling risks from asteroids and comets:[1]

  • Research the deflection of 1 km+ asteroids and comets, perhaps restricted to methods that couldn’t be weaponized such as those that don’t lead to accurate changes in trajectory.
  • Bring short-period comets into the same risk framework as near-Earth asteroids.
  • Improve our understanding of the risks from long-period comets.
  • Improve our modeling of impact winter scenarios, especially for 1–10 km asteroids. Work with experts in climate modeling and nuclear winter modeling to see what modern models say.

Further reading

Newberry, Toby (2021) How cost-effective are efforts to detect near-Earth-objects?, GPI technical report no. T1-2021, Global Priorities Institute, University of Oxford.

  1. ^

    Ord, Toby (2020) The Precipice: Existential Risk and the Future of Humanity, London: Bloomsbury Publishing, p. 277.