Large areas of those parts of the ocean bottom we call the continental shelf were exposed as dry land, and shallow ocean straits, like the Bering Strait and the Gulf of Carpentaria, were instead land bridges. These bridges served as migratory routes for the people now known as aborigines in Australia and the Asiatic nomads now known in North America as Native Americans and in South America as Indians or indigenous people. As the glaciers retreated, the sea level rose again some 10,000 years ago, stranding the Native Americans and aborigines on their new continents. At the same time, as temperatures climbed, the global climate settled into the pattern that it has roughly maintained ever since (Gore, p. 61).
As one can plainly see from the quotation above, Gores examples and his argument are rendered in clear, straightforward prose that effectively work to communicate his main idea — the fact that climate change has caused terrible disasters to occur in the natural, agricultural, political, and social realms throughout history.
It is a lesson we should learn well, as, if we continue to cause global change through pollution of the natural environment, we will be dealing with similar catastrophes in our lifetime — a situation that will only become worse in our childrens and grandchildrens lifetimes.
Gore, Al. Earth in the Balance..