We see reduced rainfall in many areas already, enough to have materially affected crop yields and triggered political instability, generating refugees. (Increased rainfall in other places doesn't help.) Insect populations are collapsing already. I don't think we know how low such populations may go before loss of pollination affects crop yields.

The only good news is that renewable power cost is still in free fall. It is not clear if it can be built out fast enough to cut CO2 output. Desalination will fill in for rainfall in some places, rescuing yields, although probably not in the places that will produce refugees.