I'm amused that when I was reading this, it didn't even occur to me that this might be about global warming - I just assumed it was about eugenics.

But fundamentally, I do think that the basic observation is right: our planning horizons should be fairly short, because we just don't know enough about future technology and developments to spend large amounts of resource on things with low option value. There are countless past crises that did not materialize or were averted by other developments; to give an imperfect list off the top of my head: horse shit in the streets of cities, the looming ice age, the degradation of the environment with industrialization, Kessler catastrophe, Y2K, and Hannu Kari's Internet apocalypse.

I am reminded of a story Kelly tells in The Clock of the Long Now about a Scandinavian country which set aside an island for growing big trees for making wooden warships in the 1900s, which was completely wrong since by that point, warships had switched to metal, and so the island became a nature preserve; this is a cute story of how their grossly mistaken forecasts had an unanticipated benefit, but being mistaken is not usually a good way of going about life, and the story would be a lot less cute if the action had involved something more serious like taxation or military drafts or criminal justice or economy-wide regulation.