Changes in the Land: Environmental Stresses and the Terrestrial Biosphere's Capacity to Store Carbon
Dr. Jerry M Melillo
Co-Director and Senior Scientist, The Ecosystems Center, Marine Biological Laboratory, Woods Hole
Jerry Melillo bears a formidable burden of knowledge. He studies the forces behind global warming, and attempts to predict how they will shape the future of the planet. Melillo's research involves both small-scale and large-scale studies, in different regions of the world, and allows him to form a truly global picture of the ways carbon dioxide is released into the atmosphere, or stored within terrestrial ecosystems.
Melillo's research in Massachusetts forests has highlighted a little known piece of the carbon cycle: If more nitrogen becomes available to plants, they grow better, and tend to accumulate more carbon-- reducing the amount released to the atmosphere. So one way of helping reduce atmospheric CO2 is feeding trees with nitrogen. But this works only to a point, since too much nitrogen, from such sources as fertilizers, washes out of the soil and into water supplies.
The bigger picture Melillo presents is grim: human land use -- specifically the conversion of forests into agricultural land -- represents an irreversible loss of the capacity of the planet to store carbon. He points to an astonishingly destructive project: China's $7 billion dollar investment in Borneo in 2005 to clear tropical forests in order to create palm tree plantations to produce biofuel. Half of Borneo's forests are already gone. Comparable enterprises are underway in Brazil, clearing forest and savannah to make way for massive soy bean plantations -- for biodiesel fuel. Melillo points to the paradox of destroying carbon dioxide storing capacity, to feed economies that will produce more carbon dioxide. "The prospects for carbon storage on land, if this activity continues -- it's not a pretty picture," he says. He also points out that as the world warms up, we must contend with more frequent forest fires, as well as the vast pool of carbon lying in cold regions, which will be released into the atmosphere as frozen soil thaws and decomposes.
"I look into a very clouded crystal ball," concludes Melillo. "Our knowledge of the global carbon cycle is incomplete and our current approach of managing it is not in the interests of human kind."
About the Speaker(s): Jerry Melillo studies how human activities are altering the biogeochemistry of terrestrial ecosystems. His research includes studies of carbon and nitrogen cycling in a range of ecosystems across the globe including arctic shrublands in northern Sweden, temperate forests in North America, and tropical forests and pastures in the Amazon Basin of Brazil. He has become increasingly committed to studying the large-scale effects of global change on terrestrial ecosystems, including effects on the chemistry of the atmosphere and on the climate system.
Melillo received his B.A and M.A.T. from Wesleyan University, and his M.F.S. and Ph.D. from Yale University.Host(s): School of Science, Center for Global Change Science
Credit: MIT World -- special events and lectures
License: MIT TechTV