Changes in climate that had already taken place are manifested __1__ from the decrease in extent and thickness of Arctic sea ice， perma- __2__ frost thawing， coastal erosion， changes in ice sheets and ice shelves， altered distribution and abundance of species. __3__ Nowadays snows melt earlier in the springtime. Lakes， rivers and bogs freeze much more later in the autumn. Reindeer herding __4__ becomes more difficult so the ice is weak and may give way. __5__ Nowadays winters are much colder than they used to be. __6__ Occasionally during winter time it rains. We never expected this; we could not be ready for this. It is very strange. The cycle of the yearly calendar has been disturbed greatly. Warming over northern land areas has been very greater than elsewhere in the world. The __7__ changes are due to human modification of the concentration of greenhouse gases during the 20th century， leading quite directly to the projections the Artic will warm by several times as much during the __8__ 21st century as it did during the 20th century. The amplified warming in Arctic， in turn， directly contributes to overall global warming， as __9__ well as cause changes that create impacts over the rest of the globe. __10__
2.from-in.manifest something in something 意思是“在……方面表现出来”。例如：His frustration manifested itself in his silence and inactiveness.
3.^altered-and.这里要看出并列的几个名次词组是 extend and thickness…、permafrost thawing、coastal erosion、changes in ice sheets and ice shelves、altered distribution and abundance of species，三个斜体的and并不是连接这几个并列项的，所以必须在最后一项altered distribution and abundance of species前加上并列连词and.
7.very-/.very不修饰形容词或者副词的比较级。(觉得这里把very 改为much 也没问题)
10.cause-causing.as well as相当于介词，其后不直接跟动词，应该是名次或动词-ing分词。