Write a summary of the article Wind Power.
Wind power currently supplies around 2 per cent of global electricity demand, with capacity more than doubling in the last four years. In Denmark, wind already accounts for one-fifth of the country's electricity production. Wind could meet a quarter of the world's electricity needs by 2050 if current growth rates continue-requiring an additional 1,000,000 onshore and 100,000 offshore turbines. Electricity from offshore wind is less variable, and turbines can be bigger.
Although wind farms have a very visible effect on the landscape, their environmental impact is minimal if they are planned sensitively. When turbines are sited on farmland, almost all of the land can still be used for agriculture, such as grazing or crops. Unlike fossil fuel and nuclear power plants, wind farms don't need any water for cooling. Both on- and offshore wind developments need to be sensitively planned to minimise the impact on marine life and birds, and more research is needed in this area. Floating turbines, which would have less impact on the seabed and could be sited in deeper water, are being trialled.