"We are already experiencing huge cost externalities from population hypergrowth and profligate fossil fuel use in the form of environmental devastation. Of the earth’s estimated 10 million species, 300,000 have vanished in the past fifty years. Each year, 3,000 to 30,000 species become extinct, an all-time high for the last 65 million years. Within one hundred years, between one-third and two-thirds of all birds, animals, plants, and other species will be lost. Nearly 25 percent of the 4,630 known mammal species are now threatened with extinction, along with 34 percent of fish, 25 percent of amphibians, 20 percent of reptiles, and 11 percent of birds. Even more, species are having population declines. Environmental scientists speak of an “omega point” at which the vast interconnected networks of Earth’s ecologies are so weakened that human existence is no longer possible."