Temperature trends in the sub-Arctic and Arctic have been notably on the rise in recent decades. In fact, in the last half century the overall annual mean Alaska temperatures have increased three to four degrees. As America’s only Arctic state, Alaska may be a proverbial canary in the coal mine for the rest of the United States when looking at the effects of climate variations. Such variations can affect water supplies, available flammable biomass fuels, or introduction of pests thus influencing crop harvests and local environments.

In the Alaska sub-Arctic and Arctic, tracking of these variations has shown a general increase in the number of frost-free soil days, a decrease in time periods with snow on the ground, an increase in precipitation and earlier river water exposures in the spring. Most concerning for many is the melting of permafrost (frozen soils maintaining their condition for 24 consecutive months or more). As thawing progresses, there is an increase in the emissions of previously locked up greenhouse gases so that organic materials locked up below the surface, without exposure to oxygen, are now free to decay with the diffusion of methane (and thus carbon).



Διαβάστε ακόμα