GRE writing, decline of the population of arctic deer and global warming

Material： 

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.

Response:

Since extinction of a species as a result of global warming is not news anymore, it is natural to attribute the decline of arctic deer population to global warming. The supposed causal relation of melting ice and its habitat loss can easily be associated with the plight of polar bear, which is reported to be endangered because it is prevented from hunting seals due to loss of ice caused by global warming. It is pretty much possible that we will see not only the last polar bear but also the last arctic deer in the near future. However, to make this conclusion, the relation between global warming and the habitat loss has to be verified and also other possible causes of the population decrease have to be eliminated as each species lives under distinct conditions.

The causal relation of global warming and melting of sea ice in the Arctic is now a consensus, and thus there is no need to question this assumption. But whether the melting of the ice means arctic deer losing the habitat or not is another issue. Research should be done on whether there have been changes in the amount of ice within the habitat of arctic deer. Also, that the distances between islands are too far for deer to swim across should be proved. It is possible that melting of ice has never affected deer migration since they just swum instead of walking to move from one island to another.

Research needs to be done to see if there have been drastic changes in the niche of this animal. One possible change is loss of food. Another is spread of a disease which is fatal or causes reproduction problem. Both are highly possible since arctic is now a popular destination of tourists and virus that did not exist before has reached the area and wiped out the main stay plants of the deer or directly killed many of them. Thus, bacteriological research on the flora in the deer habitat and the dead dear is necessary. If there is no such causes as directly increasing the deaths of the deer, the argument will be more solid than before.

Increase of the predator of the deer for some reason could be another factor. If there is an evidence that the number of the deer predator is inversely proportional to that of the deer, the global-warming culprit theory would be weakened.

Moreover, some human factors might be worth considering. Global warming is not the first anthropologic factor of a population decline. Throughout history, over-hunting has reduced the number of many kinds of species. It needs to be determined that there has been no such activity in the deer habitat. Also, the presence of hunters and tourists might have disturbed deer migration as wild life is easily put off by the hint of human presence.

There could be many more factors that challenge the argument that global warming is the cause of the decline of arctic deer population as reality is unpredictable and as many elimination of other thinkable factors should be made to make the argument strong although some intuitively clear causal relations should be taken seriously before too much assurance makes loss of species too late to stop.