HOTTER EARTH SLOWER WIND

Rising temperatures threaten wind energy: study
November 9, 2010 (CBC News)

"As global temperatures rise, wind speeds drop, says a Texas researcher who has calculated by how much and points out it will mean less wind for powering turbines.

"The conundrum is that while wind is promoted as a renewable source of energy, greenhouse gases released by the burning of fossil fuels impede the ability to produce clean electricity from wind…Wind is created when warm and cool air meet [and winds are stronger when the temperature contrast is bigger], said climate researcher Diandong Ren of the University of Texas at Austin…"

from the Ren paper - click thru for complete info

"Ren's [Effects of global warming on wind energy availability], appearing in the current issue of the Journal of Renewable and Sustainable Energy, explains that prevailing winds in the "free" atmosphere (about 1,000 metres up) are maintained by the contrast in temperatures between the polar regions and lower latitudes.

"But with global warming, temperature contrasts drop because polar regions tend to heat up faster. As the temperature contrasts weaken, so too do winds…Ren calculates that a 2 C to 4 C temperature increase at Earth's mid to high latitudes would result in a four to 12 per cent decrease in wind speeds in certain high northern latitudes."

from the Ren paper - click thru for complete info

"Wind turbines are powered by wind at lower altitudes, where local topography such as mountains, valleys and even tall buildings influence its strength. But Ren said his study [assumed that changes in the upper atmosphere are consistent with changes in the lower layer]…"

[Ren, on the lesson learned:] "[The answer is not to give up on wind but] to invest in more wind turbines to gain the same amount of energy. Wind energy will still be plentiful and wind energy still profitable, but we need to tap the energy source earlier."