Detection of Human Influence on Arctic Precipitation

The Arctic and the northern sub-polar regions are critical areas for climate change. The fluctuation of regional fresh water inflow to the Arctic Ocean modulates the deep ocean circulation and thus exerts a strong influence on global climate. By comparing observations to simulations from 22 coupled climate models, we find anthropogenic influence in the space-time pattern of precipitation change over the northern high-latitude (north of 55 deg. N) land area during the second half of the 20th century. The human induced Arctic precipitation change is consistent with observed increases in Arctic river discharge and freshening of Arctic water masses. This result, which is insensitive to the Arctic Oscillation influence on the observed precipitation change, provides new evidence that human activity has contributed to Arctic hydrological change.