QUOTE : Sienna gave him a solemn shrug. “Robert, speaking from a purely scientific standpoint—all logic, no heart—I can tell you without a doubt that without some kind of drastic change, the end of our species is coming. And it’s coming fast. It won’t be fire, brimstone, apocalypse, or nuclear war … it will be total collapse due to the number of people on the planet. The mathematics is indisputable.” Langdon stiffened. “I’ve studied a fair amount of biology,” she said, “and it’s quite normal for a species to go extinct simply as a result of overpopulating its environment. Picture a colony of surface algae living in a tiny pond in the forest, enjoying the pond’s perfect balance of nutrients. Unchecked, they reproduce so wildly that they quickly cover the pond’s entire surface, blotting out the sun and thereby preventing the growth of the nutrients in the pond. Having sapped everything possible from their environment, the algae quickly die and disappear without a trace.” She gave a heavy sigh. “A similar fate could easily await mankind. Far sooner and faster than any of us imagine.