Large wind farms might have a warming effect on the local climate, research in the United States showed on Sunday, casting a shadow over the long-term sustainability of wind power.

Carbon dioxide and other greenhouse gases from burning fossil fuels contribute to global warming, which could lead to the melting of glaciers, sea level rise, ocean acidification, crop failure and other devastating effects, scientists say.

In a move to cut such emissions, many nations are moving towards cleaner energy sources such as wind power.

The world’s wind farms last year had the capacity to produce 238 gigawatt of electricity at any one time. That was a 21 percent rise on 2010 and capacity is expected to reach nearly 500 gigawatt by the end of 2016 as more, and bigger, farms spring up, according to the Global Wind Energy Council.