In sum, the threat of climate change adds to an extensive list of environmental rationales to develop substitutes for conventional energy technologies. Notable among these substitutes are renewable energy technologies. Contemporary advocates of renewable energy carefully note that no energy technology poses zero environmental cost. Technologies designed to tap diffuse renewable resources on a large scale can require broad areas of land and significant volumes of fresh water. Hydropower can have profound ecosystem impacts, and in America may threaten plants and animals protected by the Endangered Species Act.
Biomass power can pose the same questions of sustainability as any other intensive crop production.
Spinning wind turbines occasionally kill soaring raptors, which, like wind energy developers, prize the gusts blowing through mountain passes. In addition, the manufacture, construction and operation of renewable energy technologies can raise occupational risks for workers and public health risks for others in the region of deployment. Nonetheless, shifting a significant fraction of global energy demand from carbon-intensive fossil fuels to modern biomass and other advanced renewable energy technologies is likely to have many important environmental benefits. The most important advantages may be reduced impacts on human health locally, declining risk of acid deposition and land degradation regionally, and decreased risk of rapid climate change globally.