I wasn't trying to be apocalyptic. Ecological collapse just means that many many organisms will (continue) to go extinct due to rapid changes in their environme

I wasn't trying to be apocalyptic. Ecological collapse just means that many many organisms will (continue) to go extinct due to rapid changes in their environment. That's both from direct causes (warming, ocean acidification) and from indirect causes. As far as food shortages, that just requires a significant reduction in arable land. The US will probably be fine, but countries which rely on farming/production near the coasts will suffer.