At the planetary scale, our calculations reveal strong hemispheric asymmetry of future changes in potential wind power, involving decreases across the Northern Hemisphere midlatitudes and increases across the tropics and Southern Hemisphere subtropics. The changes across the northern midlatitudes are robust responses at both mid-21st century and late 21st century time periods and in both high and low emissions scenarios, whereas the Southern Hemisphere changes appear critically sensitive to emissions scenario.
Amid these planetary scale patterns are regional variations of substantial magnitude including, for example, a roughly 15–20% decrease over the U.S. Great Plains and upper Midwest, ~10–30% increase over eastern Brazil, and ~5–40% increase over northeastern Australia at 2080–2100 (where ranges given are due to emissions uncertainty). These patterns are largely explainable through simple diagnostic fields that reveal the effect of a reduced midlatitude zonal mean meridional temperature gradient (driving the northern midlatitude decrease) and enhanced land-sea thermal gradients (driving the tropical and southern subtropical increases).
While the relatively coarse spatial and temporal resolution of the models upon which these projections are made may not allow high-fidelity predictions of wind resource that would be required for localized wind farm siting, this investigation does highlight areas around the globe where more refined investigations with downscaling can lend critical insight into the likely impacts of climate change on wind resources. Further, because the relatively coarse spatial and temporal resolution of GCMs may not fully capture important variability in wind resources, we also quantify uncertainty in these estimates. The applicability of these results to the local scale is thus addressed using several years of hourly data from tall towers in both flat and complex terrain in North America as well as atmospheric reanalysis data.