The study, headed by a researcher at the State University of New York-Albany, says that a wind farm in Texas has warmed local night-time temperatures by up to 0.72°C. This is because wind turbines create turbulence that conducts warmer night air higher in the atmosphere to the ground, where temperatures are cooler at night.
But, contrary to what some anti-wind media are claiming, local temperature effects do not have any bearing on global climate change. As scientists have long said, carbon dioxide is the biggest factor behind climate change. The UK’s Met Office says that: “the fundamental physics that links CO2 concentrations to temperature changes has been known since the late 19th century.”
CO2 causes global climate change, and the biggest source of man-made CO2 emissions comes from coal-fired power stations. In fact, Greenpeace says that “coal energy is the single greatest threat facing our climate.”
In 2010 in the EU, wind energy avoided the emission of 126 million tonnes of CO2 by displacing energy produced by the energy mix of coal, gas and oil. The European Wind Energy Association predicts that as the share of wind power in the overall energy mix grows, the annual CO2 avoided by wind energy will rise to 342 Mt in 2020 and 646 Mt in 2030.
It is a large stretch of the imagination to link the US study to climate change. In fact, one professor equates the impact of wind turbines on local temperatures to practices used by fruit growers to prevent frosts. “The same strategy is commonly used by fruit growers who fly helicopters over the orchards rather than erect windmills to combat early morning frosts,” Steven Sherwood at the climate change research centre at the University of New South Wales, Australia, said.
The study acknowledged that the change in temperature was small compared to the overall land surface temperature change, and that more studies were needed, at different locations and for longer periods, before any firm conclusions could be drawn.
While local temperature changes caused by wind turbines may be worth further scientific study, their impacts even on local temperature are far less than many other human activities such as burning fossil fuels to produce electricity and power vehicles and generating nuclear power, the heating of buildings, street lighting. Meanwhile, the wind industry itself is researching new designs that could minimise the local temperature effect of wind turbines.
Zoë Casey, http://blog.ewea.org