Despite decades of research into the complex interplays of tropical ocean conditions, land-atmosphere feedbacks, and large-scale circulation that drive the monsoon, predicting its variability from place to place and year to year remains difficult.
Traditionally, scientists have focused on studying tropical drivers such as the El Niño–Southern Oscillation (ENSO) and Indian Ocean variability. Increasingly, however, attention is turning toward processes far outside the tropics. Rapid environmental change in the Arctic, particularly the decline of sea ice, is emerging as a potential contributor to atmospheric variability that may extend into monsoon regions.
The Arctic is warming nearly 4 times faster than the global average, a phenomenon known as “Arctic amplification.” And since satellite observations of Arctic sea ice began in 1979, summer (minimum) sea ice extent has declined sharply—by about 12% per decade—exposing larger expanses of ocean surface, which absorbs more solar radiation than ice does, and accelerating regional warming [Screen and Simmonds, 2010; Serreze and Barry, 2011].