Alaskan peatlands expanded rapidly as ice age waned

Growth fueled by warm summers, cold winters

A rapid expansion of Alaskan peatlands at the end of the ice age was fueled by highly seasonal climate conditions, a new analysis suggests. The finding raises the possibility that future warming could decrease or reverse carbon storage in peatlands and thereby further aggravate climate change.

STACKING UP CARBON Mosses that grew in Alaskan peatlands less than 8,600 years ago (samples at left, second from left) have decomposed more quickly and accumulated carbon at a rate only one-fourth that of mosses that grew between 8,600 and 11,500 years ago (third from left, far right), thanks to the recent trend toward decreasing seasonality in the form of cooler summers and warmer winters.