Plants and animals have evolved over time to live in specific environmental niches. As the climate warms, parts of the ranges in which they live may no longer offer the conditions under which they can thrive. Species can respond to these changes in three ways: they can adapt to new conditions by undergoing niche shifts; they can relocate to better conditions, such as by moving to higher elevations or latitudes; or they can locally go extinct.
One of the thorniest problems arising from the changing climate is the degradation of inhabited areas that forces entire communities to relocate permanently. Basically, we don’t really have the infrastructure in place to deal with such occurrences.