Presenter: Xiangdong Zhang, IARC Professor, climate & global change

Surface air temperature increase has been amplified in the Arctic. However, the sparse observational network limits accurate estimates of Arctic warming. There is uncertainty in global warming rate, including the period of so-called “hiatus” from 1998-2012 as indicated by the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5).

We reconstructed a new global dataset with improved spatial and temporal representations of the Arctic SAT observations. The analysis suggests that Arctic SAT has increased at a rate of 0.755°C/decade during 1998-2012, more than 6 times the global average. Rather than a hiatus, the amplification significantly contributed to the global warming trend.

We also examined changes in Arctic storms and atmospheric circulation and their roles in linking Arctic and lower latitudes and causing occurrence of extreme events. The results indicate that changes in the large-scale atmospheric circulation build up a shortcut for warm and moist air flowing into the Arctic and circulate the polar cold air to the lower latitudes, causing an amplified Arctic warming and midlatitude cooling.