Arctic deer live on islands in Canada's arctic regions. They search for food by moving over ice from island to island during the course of the year. Their habitat is limited to areas warm enough to sustain the plants on which they feed and cold enough, at

The author states that because of global warming, that has caused sea ice to melt, arctic deer cannot migrate as before and so their population has declined. For this conclusion, however, he provides some evidence such as the report made by local hunters about this declination. But, before making this such a significant conclusion, more reliable evidences are required to make this argument dependable.

First of all, concerning the report by hunters, there is the possibility that deer become of aware of the presence of the hunters and hence leave the spot immediately. Thus, the hunters simply see less deer than before and report as they observe. To be more specific, some other group apart from hunters such as native people or environmentalists should report the same thing about declination, because they are not a threat to the arctic deer themselves. Besides, since the author has mentioned hunters, there should be strong and reliable evidences about the effects of hunting in the area, to be able to presume that excessive hunting is not the cause of this decrease in the number of deer.

Before making global warming the culprit, it should be clear that to what extent, global warming has affected the sea ice. Specifically, there should be evidence such as data from weather stations that a noticeable part of the ice has been melt, so that the deer are not capable of passing. Furthermore, even if the ice has been entirely melted, yet some evidence such as decrease in the population of deer's offspring or considerable number of dead deer due to climate conditions, are needed to make sure that this change in their migration pattern is directly affecting their population.

Besides, apart from the causes mentioned in the argument, other evidences are to be specified so that the reader can make sure that no other factors are possible to be engaged in this phenomenon. For example, if evidence was available that the danger of other predators or level of available nourishment is too minor to be responsible for such a decrease in population, it would have been very helpful.

All in all, in order to make his argument more reliable, the author should provide solid evidences of two types. First is, that there exists, for sure, a decrease in the deer population. Information that are suitable for this kind of conclusion should come from a source other that hunters, such as environmentalists. Then, it should be clarified with reliable data that global warming is influencing the deer’s migration pattern by melting the ice sea and that without migration population of the deer is directly influenced. But in its current state this argument is not sufficiently supported.