NOAA: Future of Arctic Sea Ice and Global Impacts
Teleconnections impact mid-latitudes
Higher pressure surfaces above the North Pole, due to the warmer temperatures associated with greatly reduced sea ice, are thought to impact large scale wind patterns over the Northern Hemisphere. Climate models show these connections with cold air moving south, producing low pressure areas and unusually cold winters in the eastern U.S. and eastern Asia, and cooler than usual weather in late winter from Europe to the Far East1,2,3,4,5 (Figure 1, below). This would be only one factor among many influencing U.S. and Eurasian weather. How do we think we know this?
|Figure 1. Severe winters in eastern US and E. Asia are related by teleconnections to changes atmospheric pressure and winds following loss of Arctic sea ice. Figure from NOAA.|
|Figure 2. Arctic Climate Feedback and its Global Implications. Figure from NOAA.|
Europe and East Asia have more severe winter stormsObservational evidence shows that the recent significant cold anomalies over the Far East in early winter and cold temperature anomalies from Europe to Far East in late winter are associated with the decrease of the Arctic sea-ice cover in the preceding summer-to-autumn seasons.
Results from numerical computer simulations using an atmospheric general circulation model support these notions (Figure 3).¹
|Figure 3. Computer simulations of unusually high constant pressure surfaces in |
the upper atmosphere (red) over regions without sea ice and unusually low pressure
surfaces (purple) over E. Asia in December. Figure from Honda, et al.1
United States has more severe winter stormsPreliminary results from numerical computer simulations indicate that
the significant cold anomalies over the eastern US in winter are
associated with the decrease of the Arctic sea-ice cover in the
preceding summer-to-autumn seasons (Figure 4, right).2
Although there is considerable year to year variability, as summer
Arctic open water area increases over the next decades, an increasing
influence of loss of summer sea ice on northern hemisphere wind patterns
can be anticipated, with resultant impacts on northern hemisphere weather.
|Figure 4. Computer simulations of unusually high temperatures (red) over regions without sea ice and subsequent unusually cold area (blue) over the eastern U.S. in the following October/November. Figure from Strey, et al.2|