The environmental impact of wind power when compared to the environmental impacts of fossil fuels, is relatively minor. Compared with other low carbon power sources, wind turbines have some of the lowest global warming potential per unit of electrical energy generated. According to the IPCC, in assessments of the life-cycle global warming potential of energy sources, wind turbines have a median value of between 15 and 11 (gCO2eq/kWh) depending on whether off- or onshore turbines are being assessed.
While wind turbine installations may cover a large area, they are compatible with many land uses such as farming and grazing, as only small areas of turbine foundations and infrastructure are made unavailable for use.
Wind turbines generate some noise. At a residential distance of 300 metres (980 ft) this may be around 45 dB, which is slightly louder than a refrigerator. At 1.5 km (1 mi) distance most wind turbines become inaudible. From a fundamental biological point of view, it is known that loud noise increases stress and stress causes diseases. Peer-reviewed research has generally supported the view that when properly sited wind turbines do not affect human health from noise. However, when improperly sited, data from the monitoring of two groups of growing geese revealed substantially lower body weights and higher concentrations of a stress hormone in the blood of the first group of geese who were situated 50 meters away compared to a second group which was at a distance of 500 meters from the turbine.
Aesthetic aspects of wind turbines and resulting changes of the visual landscape can be significant. Conflicts arise especially in scenic and heritage protected landscapes. Siting restrictions (such as setbacks) have often been implemented to limit any intrusive environmental impacts.
There are reports of bird and bat mortality at wind turbines as there are around other artificial structures. The scale of the ecological impact may or may not be significant, depending on specific circumstances. Prevention and mitigation of wildlife fatalities, and protection of peat bogs, affect the siting and operation of wind turbines.