All animals live in or seek a set of climate conditions they find tolerable. This “climate envelope” partially determines where animals are found, but the continued existence of many species now rests on the outcome of human-driven climate change.
Rising temperatures are moving the available climate niches of many species into areas which were previously too cool. While their ranges shift poleward or to higher elevations, their habitat downslope or closer to the equator shrinks, as it becomes too hot to live in.