Paul R. Moorcroft is Assistant Professor of Ecology at Harvard University and specializes in terrestrial ecosystem
dynamics.
In his presentation, Professor Moorcroft discusses the "challenges that are ahead of us in trying to preserve habitats
and diversity in the 21st century." He quantifies the vast environmental changes that humans are affecting, which include transformation
of fifty percent of the earth's surface, appropriation of fifty percent of available fresh water sources, and the problematic overuse of
sixty percent of fisheries. "We're appropriating ever larger fractions of the earth's resources for ourselves," he says, "and that is a
real challenge to preserving biodiversity."
Professor Moorcroft cites population growth as the driving force behind these environmental changes. The United Nations
has predicted that the world population will increase by three billion over the next fifty years (as it did between 1950 and 2000), and
Professor Moorcroft addresses the complexities and dangers of this massive population expansion. Although the population surge of second
half of the 20th century only resulted in a ten percent increase in cropland, this was made possible by agricultural intensification,
which doubled the yield of croplands. However, there were also increases in the use of pesticides and fertilizers, as well as in the
consumption of water. Though the doubling of yields made transformation possible, Professor Moorcroft emphasizes that "the picture
becomes a little more sobering" when we ask ourselves what we'll do with the arrival of another three billion people, and he does not
believe that we will "be able to reproduce what we did for the first additional three billion."
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