Decreased Surface Wind Speed
Observations indicate that surface wind speed has decreased in numerous sites around the globe during the past few decades and research suggests about half of the change is due to atmospheric circulation, with possible climate links. Changes wind speed can have far-reaching implications, such as on the rate of evaporation.
Large scale air circulation depends on the temperature differences between the warm equator and cold polar regions. As global warming continues, scientists expect the temperature difference between the equator and the poles to shrink, because the Arctic is warming at a rate twice the global average.
Less of a temperature difference between the equator and the poles is likely to mean slower average wind speeds. However, wind speed will not change uniformly across all regions and some regions could experience an increase in average wind speeds.
Over the past 30 years, observations indicate a decline of about −0.3 meters per second in the northern mid-latitudes land surface wind speed. By one account, the up to 50 percent of the northern mid-latitude stilling in the past 30 years may be attributed to atmospheric circulation changes.
A review study analyzing 148 studies reporting surface wind speed trends from across the globe found that the average annual trend was a decrease of –0.014 meters per second since 1950. The picture is less conclusive for the Southern Hemisphere and over the oceans.