Tropical glaciers in the Andes of Peru and the Mt. Kilimanjaro ice fields of East Africa are retreating at such an alarming rate that, if current warming trends continue, they could be completely ice free within 10-20 years, says glaciologist Professor Lonnie Thompson from Ohio State University.According to Professor Thompson, Quelccaya in Peru, the only true ice cap in the tropics, retreated 32 times faster in the last two years (1998-2000) than during the 20 years from 1963 to 1983, and the Mt. Kilimanjaro ice fields have retreated by at least 80% since 1912.
"As a result of recent global warming, many tropical glaciers around the globe may disappear completely by 2020. Apart from the dramatic impact this will have on local communities, it is also a potent sign that the Earth is undergoing enormous changes," he says.
Professor Thompson's work forms part of a large international effort, under the auspices of the International Geosphere-Biosphere Program (IGBP), to understand how the global environment is changing.
According to Dr. Will Steffen, Executive Director of the IGBP Secretariat based in Stockholm, Professor Thompson's work adds to the growing body of evidence of a rapidly changing earth.
"Retreating glaciers is one of many symptoms that the Earth is undergoing dramatic changes within our lifetime. Climate change is just one piece in a much bigger puzzle," he says.
"Many changes are taking place on the global scale with impacts that go beyond what most people can imagine. Nearly 50% of the Earth's surface, for example, has been transformed by human action, with significant consequences for biodiversity, nutrient cycling, soil structure, etc., as well as for climate."
Dr. Steffen, along with many thousands of scientists within the IGBP network, believes that the Earth is a complex system that behaves as an integrated whole.
"Large changes in one part of the system will have an impact on other parts," he says, "and understanding these changes is no simple task."
The rapidly growing field of "Earth System science" is ushering in a new era in which social scientists, economists, climatologists, etc., are working together to understand this complex system, Dr. Steffen says.
Dr. Steffen and Prof. Thompson joined three other global change experts (Professor Roger Pielke Sr., Colorado State University; Professor Emilio Moran, Anthropological Center for Training and Research on Global Change, and Dr. Inez Fung, UC Berkley) on Sunday for a special symposium on global change held at the AAAS meeting in San Francisco.
[Contact: Susannah Eliott]
19-Feb-2001
