"So the winds are able to derive greater energy from that temperature difference or instability".
A warming climate is likely to calm some of the winds that now produce electricity across the Northern Hemisphere's middle latitudes, while boosting breezes closer to the equator, according to new research by scientists at the University of Colorado.
While not all climate models agree on what the future will bring, substantial changes may be in store, especially a prominent asymmetry in wind power potential across the globe.
The findings don't disqualify wind as a competitive source of renewable energy, cautioned lead study author Kristopher Karnauskas of the University of Colorado, Boulder. "They are there because of this contrast in energy between the equator and the pole". This decline in wind power can be explained by the rapid warming in the Arctic, which is reducing the temperature difference between the Arctic and the tropics, a process that ultimately drives the intensity of storms. But the wind? It has been left out of most conversations regarding climate change. Wind happens because the Sun's light heats different parts of the planet to different levels, creating regions of high energy and low energy. The result is varying levels of atmospheric pressure around the globe, which affects the way air flows from one place to another. Karnauskas and colleagues Julie Lundquist and Lei Zhang wanted to better understand likely shifts in production, so they turned to an worldwide set of climate model outputs to assess changes in wind energy resources across the globe.
Some studies have previously investigated the issue on a small scale, using individual models or looking at specific regions of the Earth. The changes varied by location-for example, in the central USA, the study suggested wind power reductions of 8 to 10 percent by the year 2050.
On the other hand, some increases in wind energy resources were projected for the Southern Hemisphere, which could help to offset the decreases in the North-but only under the more severe climate change scenario.
"That's why we have a constant parade of weather systems", says Karnauskas. "It looks like you get some sliver of good news on the higher-emissions scenario".
Conversely, in the Southern Hemisphere, where there is a lot more water than there is land, a different kind of gradient increases wherein land warms faster than the surrounding oceans - just imagine Australia, lots of land surrounded by even more water.
But it's not all bad news either.
For Australia, Professor Karnauskas said he expected there would be a boom in wind energy for the north-east of the country.
Although the ability to generate power from wind farms is quickly growing around the world as an alternative to fossil fuels, regional studies have demonstrated that the amount of wind available for conversion into energy through the use of turbines can fluctuate in a changing climate.
Average wind power over the central United States is seen decreasing by 8 to 10 percent by 2050 and 14 to 18 percent by 2100, depending on concentrations of carbon dioxide emissions which is the main greenhouse gas responsible for global warming, the study said.
"Wind power is and should remain considered as an important part of the portfolio of renewable investments as part of the broader strategy to reduce carbon emissions", he said.