Population growth is at the root of many serious environmental problems. From the ancient Babylonians thousands of years ago, to Thomas Malthus two centuries ago, to present day neo-Malthusians, humans seem to possess an awareness of Earth's limitations in the face of growing populations. Today, our ability to accurately quantify and monitor population growth is very sophisticated. We can measure growth and make predictions about world growth with mathematical and computer models. Despite long-lasting, rapid global population growth that is only recently starting to show signs of slowing, we have thus far been able to avoid global catastrophe. Can we continue to avoid disaster?