The general reason to worry has more to do with the rate of change than the change itself, illustrated the best by this xkcd: https://xkcd.com/1732/ https://xk

The general reason to worry has more to do with the rate of change than the change itself, illustrated the best by this xkcd: https://xkcd.com/1732/ https://xkcd.com/1732/ Historically, life had a lot more time to adapt to changes in the atmosphere. Times we know of sudden changes, like the meteor that killed the dinosaurs, are mass extinctions. On one hand, we're already a mass extinction event even without considering the temperature change, so maybe it's not that much of an additional reason to worry. On the other hand, stacking even more stress onto the habitats of creatures we rely on might be the straw the breaks the camel's back as well. And that's ignoring things like sea level rise for our coastal cities, and the effect temperature changes might have on agriculture. Much like the above, the rate we're affecting the climate will not give us much time to respond to issues.