Oct 11, 2002 — In the wake of the World Summit on Sustainable Development in Johannesburg, South Africa, there's been a lot of talk about how to balance human needs with the health of the planet. Ecologists have been trying to measure the impact of humans on the environment for a number of years, with some sobering results. The Great Lakes Radio Consortium's Daniel Grosssman went to the New York Botanical Garden recently to take the pulse of the planet.