escalator effect
n.— «In the most likely outcome—a rise of 2.8 degrees Celsius by the turn of the century, according to the IPCC—400-550 birds could go extinct. If temperatures climb even more, that number would increase drastically. This is due in part to what the researchers call the “escalator effect.” Climate change can cause range shifts as species are forced to leave their current locations when conditions become inhospitable. The most familiar of these shifts are poleward—things in the northern hemisphere move north, and things in the southern hemisphere head south. But on a climate escalator, species that live at higher altitudes may have nowhere to go but up. And up. And up some more, until they reach the highest point available to them. Once that’s topped, there’s often nowhere for them to go but extinct.» —“No Room at the Top” by Eric Wagner Conservation Jan.-Mar., 2008. (source: Double-Tongued Dictionary)