Argument Arctic Deer Population

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 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 purported decline in deer populations is the result of the deer's being unable to follow their age-old migration patterns across the frozen sea.
Write a response in which you discuss what specific evidence is needed to evaluate the argument and explain how the evidence would weaken or strengthen the argument.
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The author of this argument claims that arctic deer population may be declining due to global warming. The reason behind this argument is that global warming causes sea ice to melt, disrupting the migritory patterns of the arctic deer across the frozen sea. While such a claim raises concern for the arctic population, a few questions must be answered before we could take it seriously.

First, the entire observation of this study is based on the report of local hunters, whether or not these hunters have been trained in scientific method remains unclear. But one thing is clear, that hunters would usually live in warmer areas, it could be that arctic deer population is not decreasing, but chose to migrate further north, or choose to migrate early, thus missing the hunters. Methods such as satellite imaging could provide us with a definite answer as to whether or not deer population is decreasing, which the evidence given in the passage cannot.

Assuming that the deer population is indeed decreasing, we cannot acertain it is global warming that is causing the decrease. For one thing, the effect of global warming could be relatively small, allowing enough ice for arctic deer to migrate largely unharmed, indeed, warmer climate could mean better grass, that could even boost the deer population. For another, we already know from the passage that hunters exist in the area, it could simply be that previous high numbers provided by the hunters simply indicate over hunting on the hunter's part, and the decline in population is really the surfacing of a long overdue event due to such huntings. Moreover, other random factors such as disease or famine could cause the decline. Before any of such factors could be assessed we cannot be sure to the cause of the decline in deer populations.

In sum, there are still many details not provided by the author, before such details are clarified, we cannot jump to the conclusion the author tries to convince.