Ecosystems at Glacier Margins Can Serve As Climate‐Change Laboratories

Reconstructing how biota have responded to fast-paced warming events in the past can help predict their responses to rapid climate changes in the future. Here we suggest that natural communities located near glaciers are useful laboratories for this purpose as they experienced climate changes accentuated by past ice-margin fluctuations. By reconstructing an Alaskan glacier's position over a 166-year period and measuring the periglacial air temperatures over the last 3 years, we estimate that the adjacent temperate rainforest episodically cooled and warmed by 0.5-0.7 degrees C/decade. These rates of change exceed most historical warming trends measured elsewhere on Earth and are comparable to the rates of climate warming predicted for the next century. The ring-width responses of yellow-cedar trees growing at varying distances from the ice edge illustrate the potential for using periglacial ecosystems to predict how forests may respond to rapid warming in the future.