Is existential risk reduction a good use of resources?


Details
Existential risks are threats to our future. Examples include nuclear war, some (possibly engineered) extremely lethal disease, and threats due to emerging technologies.
http://www.existential-risk.org/concept.html
The effective altruism movement is a friendly alliance containing those who see existential risk as a top priority together with those favouring more conventional causes such as poverty alleviation and animal rights.
The question to think about for this meeting is: is it sane and altruistic to try to reduce existential risk?
Sub-problems:
-
how morally relevant are the vast number of potential future generations?
-
which existential risks do we focus on?
-
how do we make existential risk reduction tractable?
-
in particular, how do we measure the risk of something that hasn't happened yet? How do we know we're reducing it?
-
overall, how does xrisk weigh against other areas of EA interest?
Also worth giving a shout-out to http://gcrinstitute.org/

Is existential risk reduction a good use of resources?