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بازسازی رکورد تغییرات یخ های قطبی برای 1450 سال

 

مقاله ای اخیرا روی نیچر منتشر شده است که رکورد تغییرات یخ های قطبی را در یک دوره ی حدودا 1500 ساله بازسازی کرده است. به نظرم چکیده ی این مقاله خود گویای بسیاری از مطالب است که در زیر آورده ام. این مقاله نتیجه گیری می کند که:

مدت و شدت کاهش در یخ های قطبی در سال های اخیر در 1450 سال گذشته بی سابقه بوده است.

لینک مقاله اینجا است.

مشخصات مقاله چنین است:

Kinnard, C., C. M. Zdanowicz, et al. (2011). “Reconstructed changes in Arctic sea ice over the past 1,450 years.” Nature 479(7374): 509-512.

و چکیده ی مقاله می گوید:

Arctic sea ice extent is now more than two million square kilometres less than it was in the late twentieth century, with important consequences for the climate, the ocean and traditional lifestyles in the Arctic1, 2. Although observations show a more or less continuous decline for the past four or five decades3, 4, there are few long-term records with which to assess natural sea ice variability. Until now, the question of whether or not current trends are potentially anomalous5 has therefore remained unanswerable. Here we use a network of high-resolution terrestrial proxies from the circum-Arctic region to reconstruct past extents of summer sea ice, and show that—although extensive uncertainties remain, especially before the sixteenth century—both the duration and magnitude of the current decline in sea ice seem to be unprecedented for the past 1,450 years. Enhanced advection of warm Atlantic water to the Arctic6 seems to be the main factor driving the decline of sea ice extent on multidecadal timescales, and may result from nonlinear feedbacks between sea ice and the Atlantic meridional overturning circulation. These results reinforce the assertion that sea ice is an active component of Arctic climate variability and that the recent decrease in summer Arctic sea ice is consistent with anthropogenically forced warming.

 

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