[moneytide]

Though most of their deaths were instantaneous (if it was large meteor) - the other half of the world would have been around for a few more seasons, before the food chain was rapidly squeezed (vaporized atmosphere from ground zero sloshing around pressure systems, sunlight inhibition from dust withering vegetation).

This is why I think that, even facing the chaotic "sloshing" due to projected >8C temperature within a century referenced in parent, a civilization that has practiced/standardized/mass-produced greenhouses at a hectacre-scale could fare well despite the projected drought/storm/fire/sea-rise/permafrost-methane-feedback that is being suggested as consequence. The only "silver bullet" specialty that I know would be beneficial at any point in the future anyways (ability to grow large variety of food in barren areas with limited resources).

Norway has large greenhouse production for higher latitude growth. Commercial sized greenhouse footprint to replace existing traditional outdoor grazing and staple crops would be enormous, which is why it may be more efficient to think of how to modify a biome instead of mass producing plastic/glass/steel enclosed micro climates (which may not be compatible with traditional tractors/combines/dusters which have long been mass produced).