A recent column (which came to my attention through Google news alerts) repackages stale alarums as news. The claim that global warming is killing
Caribbean basin frogs comes from a study in Nature by Pounds et al. (2004). The researchers did not argue that global warming was baking the frogs to death. They couldn't, because there hasn't been much warming in the tropics. Rather, they argued that global warming was increasing cloud cover, shielding the frogs from sunlight, which disinfects them from a fungus carried by parasites known as chytrids.
Virginia State Climatologist Patrick Michaels exposed the fallacy in this argument. First, there is no known relationship between global warming and cloud cover. Second, cloud cover in the region did not change during the researchers' period of study (1984-1996).
Michaels cited research indicating that the real culprit was inadvertent human introduction of the chytrid fungus into the frogs' habitat.
As to the claim that "hundreds of species have already changed their ranges," that may be correct. But when those amazing Idsos—Sherwood, Keith, and Craig—reviewed the literature on this topic, they found case after case of species being able to live and even thrive in latitudes and elevations that were previously too cold. They found no case in which species had become environmental refugees fleeing from the heat.