温室效应(greenhouse effect)
随大气中二氧化碳和某种其他气体增多，地球表面和大气层下部有增强趋势的变暖现象。来自太阳的可见光辐射线到达地表并使之加热。一部分这种热能又以长波红外辐射形式被地表反向辐射回去，其中很大部分被大气中的二氧化碳和水蒸气的分子所吸收，一部分作为热能反射回地表。这大致同温室窗玻璃所产生的效应类似︰温室窗玻璃能使可见波段的日光透过，但把热量阻止在室内。这种红外辐射的被捕获促使地表和大气下层变暖，温度比没有大气的情况下要高。由於现代工业社会普遍燃烧化石燃料（煤炭、石油和天然气）引起大气中二氧化碳含量升高，使得地球上的温室效应可能得到加强，亦可能造成长期的气候变迁。其他微量气体，如氯氟烃、氧化亚氮和甲烷之类在大气中浓度增加，可能也会使温室条件更加严重。据估计自工业革命开始，大气中二氧化碳量增加了30%，同时甲烷量增加了两倍。今日美国承担所有人类制造的温室气体排放的1/5左右。亦请参阅global warming。
English version：
greenhouse effect
Warming of the earth's surface and lower atmosphere that tends to intensify with an increase in atmospheric carbon dioxide and certain other gases. Visible light from the sun heats the earth's surface. Part of this energy is reradiated in the form of long-wave infrared radiation, much of which is absorbed by molecules of carbon dioxide and water vapor in the atmosphere and reradiated back toward the surface as more heat. This process is analogous to the glass panes of a greenhouse that transmit sunlight but hold in heat. The trapping of infrared radiation causes the earth's surface and lower atmosphere to warm more than they otherwise would, making the surface habitable. The increase in atmospheric carbon dioxide caused by widespread combustion of fossil fuels may intensify the greenhouse effect and cause long-term climatic changes. An increase in atmospheric concentrations of other trace gases such as chlorofluorocarbons, nitrous oxide, and methane may also aggravate greenhouse conditions. It is estimated that since the beginning of the industrial revolution the amount of atmospheric carbon dioxide has increased 30%, while the amount of methane has doubled. Today the U.S. is responsible for about one-fifth of all human-produced greenhouse-gas emissions. See also global warming.