How we can learn from the past
Although Uniformitarianism [1] is no longer accepted as a wholly valid theory, the inverse of this theory - that the past can be used to predict our future - can be used to view our current situation in the context of past natural mass extinctions, and learn how through adaptation life on earth might change in order to survive the age of humans, and whether we risk damaging complex life beyond what evolution can cope with. With the Earth's sixth large mass extinction well under way yet at the same time fully under our control, it would be foolish not to ask these questions.
References:
[1] http://geography.about.com/od/physicalgeography/a/uniformitarian.htm
[1] http://geography.about.com/od/physicalgeography/a/uniformitarian.htm