Roughly speaking: a 90 metre wind turbine (300ft) reaches 135 metres (450ft) with its blade tip and has an output of 2-3 megawatts; 20 of these would need a site extending over 160 hectares (400 acres). A conventional power station produces 500 megawatts.
The UK Government set a goal of generating 33 gigawatts of electricity from wind power by 2020, compared with an existing capacity of 1GW (1000 megawatts) around 2008.
The Intergovernmental Panel on Climate Change projects that temperatures will rise over the next century by between 2 and 11.5 degrees F, depending partly on how successful we are at reducing greenhouse gas emissions. The melting of the Greenland ice sheet would raise sea levels by 7 metres.
CO2 concentrations in the atmosphere increased from approximately 280 parts per million (ppm) in pre-industrial times to 382 ppm in 2006 according to the National Oceanic and Atmospheric Administration’s (NOAA) Earth Systems Research Lab, a 36 percent increase. Almost all of the increase is due to human activitiies (IPCC,2007). Concentration passed 400ppm in 2013.