The Role of Arctic Sea Ice
The loss of Arctic sea ice increases the warming effect that is altering our climate. As the earth’s natural air conditioner, white sea ice moderates solar heating by increasing the reflectivity of Earth’s surface and decreasing the amount of heat that would otherwise by absorbed by darker ice-free Arctic seas.
The loss of the air conditioner effect creates a feedback loop that accelerates global warming. Melting sea ice also releases greenhouse gases from thawing permafrost and frozen methane from the ocean bottom. These feedback loops could have catastrophic consequences for the climate if triggered.
Regardless of approach, all projections indicate an eventual sea ice-free Arctic with continued emissions of greenhouses gases, threatening the invaluable ecosystem service the Arctic sea ice provides while simultaneously exacerbating global warming.
The impacts and implications of rising temperatures and melting ice in the Arctic extend beyond just the Arctic itself. Changes in the Arctic led by sea ice loss are affecting weather patterns farther south, such as in the lower United States. The loss of Arctic summer sea ice and the rapid warming of the continent could be altering the jet stream—and thus weather patterns—over North America, Europe and Russia, increasing the likelihood of extreme weather events and driving winter storms south.
The jet stream
Several mechanisms have been proposed that link variability in Arctic sea ice with mid-latitude winter weather. Progress in understanding this connection has converged on two key factors: (1) the variability of autumn snow cover in Eurasia, and (2) the variability of sea ice coverage in the Barents- Kara Sea during late fall and early winter. Numerous recent studies based on both observations and model simulations indicate that reduced Barents-Kara sea ice in late fall favors a strengthened and northwestward expansion of the Siberian high, increased poleward heat flux, weakened polar vortex, and ultimately a negative AO.
Because low Barents-Kara sea ice and high Eurasian snow cover favor northwestward expansion of the Siberian high, this atmospheric pattern increases the probability of driving cold Siberian air southeastward into populous East Asia.