But the biggest change in Earth’s energy budget by far over the past hundred years is due to the accumulation in our atmosphere of greenhouse gases, which limit the exit of heat into space. Owing to fossil-fuel emissions, there is now one-third more carbon dioxide in the atmosphere than at any time in at least a million years, as the latest ice drilling in Antarctica has revealed.
所有的天气都是由能量推动的，而这些能量的最初提供者则是太阳。但过去几百年来地球能量总量中最大的变化推动力其实是大气中积累的温室气体，因为他们限制了热量向外太空散失。由于来自化石燃料温室气体的排放，当今大气中的二氧化碳含量比100万年前多了1/3，而冰川的崩坍则印证了这一点。