Methane concentrations have more than doubled over the past 100 years, which could explain part of the changes in the high-flying clouds over the past decades.
英
美
- 在过去的100年里,空气中甲烷的浓度增加了两倍以上;而这可以从某个方面解释过去几十年来对高空浮云的疑惑。