I think that eco-systems do move to higher latitudes when the earth warms. This happened e.g. at the transition from ice ages. However the problem is that if the rate of warming is too high, eco-systems will not be able spread and adapt fast enough, leading to a net loss of bio-mass.

See e.g. page 3 of https://www.pnas.org/content/pnas/115/33/8252.full.pdf on biogeophysical feedback.

I am afraid the warming rate anticipated currently is at least an order of magnitude higher than any climate changes the earth faced before.