The dramatic changes in the Arctic climate system during recent decades are one of the most prominent features of global climate change. Two most striking and fundamental characteristics are the amplified near-surface warming at a rate twice the global average since the mid 20th century, and the rapid decline of sea-ice extent at a pace of 12.9% per decade and thinning of ice thickness by 40% since 1979. In conjunction with these changes, the frequency of occurrence of extreme climate and weather events has ostensibly increased across the Northern Hemisphere mid-latitudes, including adverse cold spells, severe heat waves, destructive floods, and persistent droughts. The fact that Arctic climate changes have coincided with an increase in the frequency of occurrence of extreme events has inspired broad interest in possible linkages — not only in the climate community, but also the general public, media agencies, and decision makers — in particular considering the projected future continuation and acceleration of Arctic warming and sea-ice decline.