[ExI] libertarian (asteroid) defense

Anders Sandberg anders at aleph.se
Thu Mar 3 00:12:54 UTC 2011

Damien Sullivan wrote:
> On Wed, Mar 02, 2011 at 11:10:10AM +0000, Anders Sandberg wrote:
>> To get back to the theme of the thread, it just hit me that biofuels
>> are also disastrous from an asteroid damage perspective: an impact
>> winter, and we will neither have food, nor fuel.
> Might ruin solar power too.  Might; a slight dimming could mess up
> temperatures without removing that much light.  Don't know how dark
> nuclear/impact winters are supposed to be.

Yes. According to Robock et al. ( 
http://www.envsci.rutgers.edu/~gera/nwinter/nw6accepted.pdf ) their 
worst scenario of nuclear winter (150 Tg of soot) reduced insolation by 
100 W/m^2, and there was still -20 W/m^2 10 years after the event. That 
reduces solar power efficiency a great deal, although it does not stop.

This kind of scenarios are very sensitive to the kind of dust and soot, 
and how far up it gets lofted. I have seen papers arguing that meteor 
impacts produce very different effects depending on where they hit: the 
Chesapeake bay and Popigai impacts did not seem to cause mass 
extinctions, perhaps because they fell on the "right kind" of landscape 
that did not produce much aerosols.

As impact defense goes, surviving a nuclear/impact winter seems to be 
somewhat doable: maintain large imperishable food stores, agricultural 
equipment and seed for restarting farming once the climate recovers. The 
big question is optimal location: on higher latitudes you need plenty of 
heating or thermal isolation. Being close to the sea is useful for 
thermal balancing and the possibility of fishing, but risks being hit by 
a tsunami if there is a meteor impact in that ocean. Usual issues of 
social order: lone survivalists are unlikely to survive well or retain a 
tech basis, larger groups have better chances (and in the face of 
disaster tend to be rather cohesive; the threat is likely long-term 
fatigue during a drawn-out struggle), really large groups likely suffers 
from societal collapse issues. Crews of atomic submarines can likely 
ride out this kind (and pandemic) disasters, but they lack agritech, 
might have some morale problems after a few years and do not have the 
appropriate gender composition. The real survivors will likely be the 
employees at Walmart logistics centers rather than Mad Max.

Anders Sandberg,
Future of Humanity Institute
Philosophy Faculty of Oxford University 

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