Studying Extinction Level Impacts from Near Earth Objects
This is a briefing paper I produced for a conference on Studying Existential Risks—LSE CARR 27 June 2014
“Studying Extinction Level Impacts (ELI’s) from Near Earth Objects (NEOs) such as comets and asteroids”
Dr Jill Stuart, LSE and Space Policy journal
A) What is the current thinking about ‘existential risk’ in your field
I study the risk of extinction level impacts and possible mitigation activities with regards to comets and asteroids. I have approached this from a social constructivist perspective and also with regards to transnational regime building. I am particularly interested in: how the threat is calculated ‘scientifically’; how and why the wider public perception of risk is then dispersed and reconstitutes ‘accepted’ understandings of the risk level; what the subsequent reaction is (or might be) from policy makers and the specialist astronomical epistemic communities. Could activities to mitigate such a disaster potentially pose a greater risk than the original threat itself?
B) What are the key differences that distinguish ‘existential risk’ from ‘normal’ or ‘systematic’ risks?
In the case of NEOs, I would suggest that a lot of it is perception, which is shaped by scientific research, media and politics.
Scientists have used data from past impacts, as well as existing knowledge about orbiting NEOs, to calculate risk. This research suggests that asteroids larger than 50 meters impact earth at 100 year intervals (on a par to the Tunguska Event in Siberia 1908); that asteroids larger than a kilometer occur on average every few hundred thousand years; and that objects 10 to 15 kilometers (on a par with the Chicxulub asteroid which likely killed the dinosaurs) occur once in every 1,000,000 centuries.
Such calculations have obvious shortcomings and are highly subject to interpretation. As with any statistic, outlier events may occur and thus a hazardous NEO could theoretically approach earth at any time—or at far longer intervals than as calculated above. Thus until significantly more information is gathered about NEOs, the perception of risk is based on fluctuating information and human perception.
The perception of threat in the wider public is influenced by media, better NEO detection and reporting, further scientific study of past impacts, and even two particularly bad Hollywood movies. Several examples: In the 1980s it became generally accepted that a comet caused the mass extinction of the dinosaurs; in 1994 the aftermath of the collision of the Shoemaker-Levy-9 Comet with Jupiter which was visible even through amateur telescopes; two blockbuster Hollywood films in the 1990s about the topic (Armageddon and Deep Impact) increased media coverage of near-earth objects passing relatively close to earth; since the 2000s some scientists have argued that asteroids or comets caused four out of five of earth’s past major extinctions including the “great dying” 250 million years ago wherein 90% of marine life and 80% of land life became extinct.
This is also, however, a highly political issue as the securitisation of NEOs could open the door for some mitigation activities that may carry a far greater risk than NEOs themselves (next question)….
C) What are the challenges for risk regulation approaches that are being used to address existential risks?
On the topic of NEOs, in the first instance, detection is the priority, and an impressive epistemic network has developed around the world since the 1990s for this purpose.
More controversially is the issue of deflection. This would require either destroying the NEO, or changing its orbit. Proposals of how to do so have included a solar sail, or the use of significant weapon power (possibly nuclear) or no-mass to destroy or deflect the object. Rendezvous with remote comets have already been undertaken by Japan and the US, but it is worth considering whether experimenting with deflection may in itself be too hazardous, and whether doing so could (as so much of outer space activity does) provide a way for states to justify extraterrestrial activity with military implications.
D) What are the challenges of studying existential risk?
Disentangling the ‘science’ from perception, interpretation, and politics.