Also called natural gas, methane is released from landfills, from coal mines and rice paddies, from billions of termites that swarm through the freshly cut forestland, from the burning of biomass and from a variety of other human activities.
甲烷也被称为天然气，是从垃圾堆、煤矿、稻田、在刚刚遭到砍伐的林地成群爬过 的几十亿白蚁、被燃烧的一个地区的生物量以及从人类其他各式各样活动释放出来的。
Even though noctilucent clouds were sometimes seen in the past, all this extra methane carries more water vapor into the upper atmosphere, where it condenses at much higher altitudes to form more clouds that the sun's rays still strike long after sunset has brought the beginning of night to the surface far beneath them.
虽然过去有时也能看到夜光云，但是由于所有上述这些外加的甲烷把更多的水蒸气带 人大气层的上层，这样水蒸气就在比以前高很多的高处凝固，形成更多的云。结果，当日落 开始把黑夜带到远在这些云下的地球表面很长时间以后，太阳的光线仍然照射在这些云上。
What should we feel toward these ghosts in the sky? Simple wonder or the mix of emotions we feel at the zoo?
对天空中那些可怕的景象我们应该作何感想呢？只是惊奇还是我们在动物园里所感到的那种矛盾心情呢？
Perhaps we should feel awe for our own power: just as men tear tusks from elephants' heads in such quantity as to threaten the beast with extinction, we are ripping matter from its place in the earth in such volume as to upset the balance between daylight and darkness.
也许我们应该对自己的强大力量感到敬畏：就像人从大象头上拔下如此之多的象牙，以致使这种动物面临灭绝的威胁一样，我们正在强把如此大量的物质撕离它们在地球上的位置，以致破坏了白天与黑夜的平衡。
In the process, we are once again adding to the threat of global warming, because methane has been one of the fastest-growing greenhouse gases, and is third only to carbon dioxide and water vapor in total volume, changing the chemistry of the upper atmosphere.
在这样做的过程中，我们又一次增加了地球转暖的威胁，因为甲烷是增长最快的暖房气体之一，其总量仅次于二氧化碳和水蒸气而居第三位，从而改变了大气层上层的化学成分。