In any case, even if the Earth as a whole was much warmer on average that just means that you'd get the average temperatures that now occur closer to the equator (where some of the largest land mammals presently live) closer to the poles.
So higher average surface temperatures shouldn't preclude the existence of larger mammals.
> Given current trends, the majority of animals of today will be unable to adapt to the new climate, and will die off.
I think this has less to do with climate change per-se, and more to do with the widespread ecological destruction that's followed industrialization, and the reduction in wild habitats.
Although there's surely some species that'll go extinct mainly due to temperature changes, e.g. ones confined to a small atoll that'll get overrun by sea levels rising.
Based on the context of your first comment I thought you were trying to argue that the environment isn't really in trouble. If you agree that humans are negatively impacting the environment, that's good enough for me :)
> At the moment, climate projections are that within the next few centuries we will reach temperatures not seen since the eocene.
That seems about right, see e.g.: https://www.marum.de/en/Dr.-thomas-westerhold/CENOGRID.html
> The mammals of the eocene were quite small, because larger mammals had trouble surviving the hot climate.
What makes you think mammal size was limited by the temperature differences we're discussing?
I think the predominant theory is that the asteroid impact killed off the larger ones, and it took a while for larger mammals to evolve. See e.g.: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7645244/
In any case, even if the Earth as a whole was much warmer on average that just means that you'd get the average temperatures that now occur closer to the equator (where some of the largest land mammals presently live) closer to the poles.
So higher average surface temperatures shouldn't preclude the existence of larger mammals.
> Given current trends, the majority of animals of today will be unable to adapt to the new climate, and will die off.
I think this has less to do with climate change per-se, and more to do with the widespread ecological destruction that's followed industrialization, and the reduction in wild habitats.
Although there's surely some species that'll go extinct mainly due to temperature changes, e.g. ones confined to a small atoll that'll get overrun by sea levels rising.