目前，全球变暖是一个热门话题，但是有关全球变暖的各项证 据似乎还有些不同的声音。人们现在已经知道，地球的发展经历了 很多周期(cycle),尽管在历史上还未出现过像今天这样的时代，即 高度工业化(industrialization)产生如此多的污染。全球变暖主要是由 于二氧化碳气体(carbon dioxide)的增多。

　　Global warming is the hot topic around the world at this time but, there is also dissention about the evidence being presented to support the argument. The earth is known to go through cycles; although the past has never produced an age of so much industrialization causing the pollution currently being experienced. A major source of the problem is the increase in carbon dioxide levels.

(责任编辑：田学江)