Tiny Iceland is a prime exemplar of the complexities wrought by warming climate. It is 11 percent covered by ice, but it is basically also one very large, very active volcanic system. The island has seen fast-increasing temperatures since the 1970s, and glaciers–a big source of tourism and runoff for hydropower–are visibly receding. This cuts various ways. Iceland gets almost all its electricity and heat from hydropower and geothermal wells. Increased glacial runoff means increased generation potential; on the other hand, in 50 or 100 years, Iceland may be mostly land and very little ice, and the runoff could dry up.