we have no guarantee we can survive in any climate other than the one we evolved in
Except historical precedent. Even low-tech humans have adapted to a huge range of climates. Think Inuit living on the edge of Baffin Bay, and Bedouins living in the deserts of Sudan.
Technology can't provide us with food when none of our crops can grow anymore.
Think veggies growing in greenhouses that are either cooled or heated -- depending on which way climate change goes -- by nuclear power plants. Is that not an example of technology providing us with food?
(Nevermind that global warming will cause the amount of arable land to increase. There are huge tracts of land in Canada, Siberia and Alaska that will be farmed if the growing season gets a little longer.)
I'm not saying mucking with the climate is a good idea. But your dire predictions of possible human extinction are right out; they're the kind of alarmism that destroys credibility.