I met a traveller from an antique land, Who said — “Two vast and trunkless legs of stone Stand in the desert. . . . Near them, on the sand, Half sunk a shattered visage lies, whose frown, And wrinkled lip, and sneer of cold command, Tell that its sculptor well those passions read
fossil record show rich life at higher temps . alligators in wyoming and palm trees in canada
Until it goes even higher. The release of sub-permafrost and continental slope methane deposits will push it way past the balmy arctic stage before the feedback ends and equilibrium is regained.
IIRC, there was a time period when tropical forests were found as far north as North Dakota in the Americas, and there was deciduous forest within the Arctic Circle. That gives some idea of what the biota would be like in a warmed world, about 1 million years from now that is. A big bottleneck awaits us though and I’m thinking that also includes enough scarcity to mean famine will be thing on the far end of declining net energy, maybe as soon as later this century (though earlier for low income nations).