Yeah, because there exist short humans and so their genes would indeed be passed on. Now check that for all organisms relevant to our food chain (assuming we ev

Yeah, because there exist short humans and so their genes would indeed be passed on. Now check that for all organisms relevant to our food chain (assuming we even know which ones those are, and assuming we only care for ourselves and the rest can go extinct) there is a sufficient number of individuals in the relevant places able to cope with droughts, heat waves, flooding, storms, and other extreme weather introduced in the new climate. It doesn't magically just solve itself, even if that's the easiest thing to tell yourself and look for confirmation bias for.