The development of wind energy is indispensable in the pursuit of global carbon neutrality. Following decades of climate change, China's annual average wind speed has shown a clear decline, but the rate of this decline and its potential impacts on the need for wind power development in China have not been quantified. Here, we reveal that China's observed wind speed has declined significantly at -0.169 m/s/10 yr, 33.33 times the rate predicted by the Coupled Model Intercomparison Project (CMIP) of World Climate Research Programme, indicating a severe underestimation by those models. We attribute this underestimation to CMIP neglecting the atmospheric boundary layer height and greatly underestimating the Arctic amplification effect on wind speed. Scenario analyses demonstrate that China’s future wind power installed capacity, investment costs, and land area occupied based on the observed trend scenario will increase by approximately 53% compared to any trend of three (high, medium, and low) CMIP emission scenarios in order to meet China’s wind-generated electricity target and carbon peak emission goal in 2030. Hence, formulating its wind energy development plans based on these CMIP scenarios’ trends will prevent China from meeting its low-carbon electricity generation of carbon peak emission target by 2030 and delaying the 2060 goal of carbon neutrality, emphasizing that the CMIP models urgently need to be improved. These findings should serve as a warning to countries throughout the Northern Hemisphere to formulate wind power development plans in consideration of the climate change impacts in the pursuit of global carbon neutrality.