Global catastrophic and existential risks communication scale

Peer-reviewed paper by Alexey Turchin, David Denkenberger
Published on 10 January 2018


  • We suggest a color coded scale to communicate the magnitude of global catastrophic and existential risk.
  • The scale consists of 6 color codes from white to purple.
  • Color estimations are primarily based on probability intervals for human extinction risks in the next 100 years.
  • Each risk’s estimation could be adjusted to communicate other aspects of risk’s severity.
  • The scale is extended to cover smaller global catastrophic and civilizational collapse risks.


Existential risks threaten the future of humanity, but they are difficult to measure. However, to communicate, prioritize and mitigate such risks it is important to estimate their relative significance. Risk probabilities are typically used, but for existential risks they are problematic due to ambiguity, and because quantitative probabilities do not represent some aspects of these risks. Thus, a standardized and easily comprehensible instrument is called for, to communicate dangers from various global catastrophic and existential risks. In this article, inspired by the Torino scale of asteroid danger, we suggest a color coded scale to communicate the magnitude of global catastrophic and existential risks. The scale is based on the probability intervals of risks in the next century if they are available. The risks’ estimations could be adjusted based on their severities and other factors. The scale covers not only existential risks, but smaller size global catastrophic risks. It consists of six color levels, which correspond to previously suggested levels of prevention activity. We estimate artificial intelligence risks as “red”, while “orange” risks include nanotechnology, synthetic biology, full scale nuclear war and a large global agricultural shortfall (caused by regional nuclear war, coincident extreme weather, etc.) The risks of natural pandemic, supervolcanic eruption and global warming are marked as “yellow” and the danger from asteroids is “green”.

This paper was published in a Special Issue of Futures edited by Dr Adrian Currie, which collected many papers which were originally presented at our first 2016 Cambridge Conference on Catastrophic Risk in 2016.

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