All weather is driven by energy, and the sun ultimately provides this energy. 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驱动的，而这种能量最终都来自太阳。但100年来地球能量“预算”的最大变化是由于大气中温室气体的积累，由此限制了热量向外层空间的释放。最近对南极地区冰层的钻探表明，由于石化燃料的排放，目前大气中的二氧化碳含量比过去至少100万年中的任何时期都高1/3以上。
