With rising temperatures, there will be natural selection pressure on all organisms, many on which the economy relies (say plants).

Organisms that repeat their lifecycle faster will have advantage over organisms with longer lifecycles (the shorter-lived adversarial species among 2 adversarial species can iterate variations faster sequentially, regardless if the 2 adversarial species are competing or predator-prey, ...).

Organisms that have higher population counts will have advantage over organisms with lower population counts (since the species with higher population counts is trying out more variations in parallel)

Hence smaller, simpler organisms will cause lots of diseases and afflictions in say agriculture, which probably will adversely affect our economies...

A 10% hit on GDP sounds like a ridiculous underestimate