Abstract: This paper summarizes and assesses the possible impacts of wind farms on both short- and long-term climate changes both in global and regional areas. Based on the most observed studies and numerical simulations, it is found that the wind speed in the downwind regions of wind farms reduced obviously due to the wind farms?operations. The temperature in the downwind regions became higher or lower than the upwind regions. It depended on the atmospheric stability in the near surface. Based on some numerical simulations, if many large wind farms are designed and set up in the world, for example, the global wind energy accounts for 10% of the total energy, it means that 30%-40% of the global lands and the shallow water of the global oceans are the wind farms, it might cause global warming, and also cause the reduction of wind speed and other climatic effects. Up to now, there are large gaps and uncertainties in the assessment of impacts of wind farms on the global climate change.