1.Over the past few years one of thebiggest questions in climate science has beenwhy, since the turn of the century, averagesurface-air temperatures on Earth have notrisen, even though the concentration in theatmosphere of heat-trapping carbon dioxide hascontinued to go up.
参考译文：在过去的几年中，气候科学中最大的问题就在于，为什么，自从本世纪以来，即使大气中吸热的二氧化碳气体聚集的越来越多，地球表面平均的气温也没有上升。
2.This“pause” in global warming has been seized on by those skeptical thathumanity needs to act on to curb greenhouse-gas emissions or even (in the case ofsome extreme sceptics) who think that man-made global warming itself is a fantasy.
词汇突破：seized on 抓住(并利用);
those skeptical that +句子:这种用法在传统的语法中并不多见，但是在经济学人这样的杂志中还是挺多的。
其实就等于those who doubt that+句子 ,大家记住就好。
参考译文：全球变暖的暂停被这些人抓住并加以利用。他们本来就不认为人类需要采取行动来控制温室气体的排放。甚至其中一些极端的质疑者认为人为的全球变暖本身就是一种幻想而已。