NOAA’s 2017 Arctic Report Card Shows Transition Toward Not-Normal Polar Environment Continues
The average surface air temperature for the year ending September 2017 is the 2nd warmest since 1900; however, cooler spring and summer temperatures contributed to a rebound in snow cover in the Eurasian Arctic, slower summer sea ice loss, and below-average melt extent for the Greenland ice sheet.
Long-term trends (1982-2016) show greening on the North Slope of Alaska, the southern Canadian tundra, and in the central Siberian tundra; tundra browning is found in western Alaska (Yukon-Kuskokwim Delta), the higher-Arctic Canadian Archipelago, and western Siberian tundra.
High latitude fire regimes appear to be responding rapidly to environmental changes associated with a warming climate; although highly variable, area burned has increased over the past several decades in much of Boreal North America. Most acreage burned in high latitude systems occurs during sporadic periods when lightning ignitions coincide with warm and dry weather that cures vegetation and elevates fire danger. Under a range of climate change scenarios, analyses using multiple approaches project significant increases (up to four-fold) in area burned in high latitude ecosystems by the end of the 21st century.