【Flyer杀G】小组-7.26作业 argument45

wagner1985UID: 2838595

45. The following appeared as an editorial in a wildlife journal.
"Arctic deer live on islands in Canada's arctic region. They search for food by moving over ice from island to island during the course of a year. Their habitat is limited to areas warm enough to sustain the plants on which they feed, and cold enough, at least some of the year, for the ice to cover the sea separating the islands, allowing the deer to travel over it. Unfortunately, according to reports from local hunters, the deer populations are declining. Since these reports coincide with recent global warming trends that have caused the sea ice to melt, we can conclude that the decline in arctic deer populations is the result of deer being unable to follow their age-old migration patterns across the frozen sea."

难度：号称最难的Argument了



Judging from the habits of deer, the author takes the tendency of the global warming into the consideration and therefore draws such a conclusion that the diminishing of deer derives from the melting of huge ices incurred by the increasing temperature. However, the statement relies on a series of unproven assumptions.
To begin with, the decreasing of the real number of the population, which the statement focuses on, may not even exist. The mere evidence is the reports from local hunters which may not be precise estimation. As the habits of deer which mentioned before, the deer is likely to move around the islands which are cut across by the diminishing sea ice and take a longer time to return to the same place because of the disappearing of bridge among islands. And the local hunters have lower possibility to catch the same number of deer in the fixed time as before. And the author does not exclude such a possibility, either: before or during the global warming, some of the deer may have finished  emigration to the place for the reason that their habitat is limited to areas warm enough to sustain the plants on which they feed, and cold enough, at least some of the year, for the ice to cover the sea separating the islands. The few ices may force the deer go to the place in the north where have more ices to go along. So the number would remain the same level, the local hunters just cannot see as much as before.
Furthermore, even if the global warming melts some pieces of the ices, it is not impossible for deer to go around different islands for certain. Because unless not all of the ice was melted, there are still some pieces or parts of ices remain on the sea which retain the possibility of migration patterns. Nor the author did tell us anything about whether the deer is capable of swimming on the sea. If that so, without any piece of huge ices, the deer can still move along the routine of immigration or change to another path.

Also, even if the global warming make the immigration impossible, the decrease of deer number may still ascribe to other factors with or without the influence of global warming. For example, the more difficulty of immigration provides more opportunities of being killed, because the deer cannot leave freely but stand in the only islands. Or else, even without interference of the global warming, the more killing would directly aggravate the diminishes of the deer, which have not be implicitly considered by the author.
In sum, to strengthen the argument, the author has to provide more details about the fact that the number of deer is really diminished and the habits of deer. Also, the other possibilities should be provided for any reason.