Regional Climate Change in the Northern Hemisphere

Abstract:

It has been widely recognized that climate warming was greater in cold regions than elsewhere on the Earth. Using the CRU TS 3.21 datasets, we investigated regional climate change over a period from 1901 through 2012 with latitudes, elevation, and long-term mean annual precipitation, aridity index (AI), and annual air temperature (MAAT) in the Northern Hemisphere. We found that the amplified warming occurred in the mid-high latitude regions between 50 and 60 ºN, where air temperature increased by about 1.6℃; in semi-arid regions where annual precipitation between 200 and 500 mm; in mid-high altitude regions between 1000 and 1500 m with air temperature increase of about 1.2℃ and the changes in regions higher than 3500 m seemed to intensity with elevation. Over the transition regions between humid and semi-humid regions with AI between 0.5 and 1.0, air temperature has increased by 1.4℃. Cold regions, defined as the long-term MAAT at or below 0 ºC, air temperature has increased by 1.4℃.Cold regions are more sensitive to the warming, and regional temperature increased greater than that changes across the NH (1.11 ºC). The cryosphere in cold regions plays a critical role in the increased warming as well as in the positive feedback.