April 21, 1999

Climate Expert Michael MacCracken to Talk on "Global Warming: The Increasing Effects of Human Activities on Climate" at Middlebury College on April 28

Michael MacCracken, a senior figure in the United States Global Change Research Program (USGCRP), will give a talk, titled "Global Warming: The Increasing Effects of Human Activities on Climate," at Middlebury College on Wednesday, April 28 at 7 p.m. The event will take place in the library of the Geonomics Center for International Studies on Hillcrest Road off College Street (Route 125), and is free and open to the public.

MacCracken is executive director of the National Assessment Coordination Office of USGCRP, the portion of the program responsible for assessing how global warming will impact the United States. His talk is the 1999 Scott Margolin Lecture in Environmental Affairs.

The lecture will include a number of topics related to the cause of global warming, the evidence that it is occurring, and its impact on the world. McCracken will discuss the fact that emissions from fossil fuel combustion, deforestation, and non-sustainable agriculture are releasing carbon dioxide, methane, and other greenhouse-effect gases into the atmosphere, thereby altering atmospheric composition.

He will point to evidence-including rising ocean and land temperatures, melting glaciers, the rising sea level, and increasing rates of precipitation-that suggests human activities are now having a discernible influence on the global climate.

MacCracken also will discuss prospects for the next century that global average temperatures will rise one to three and a half degrees centigrade, and that the sea level will rise by 10 to 95 centimeters by the year 2100 if emissions are not reduced below projections, and he will also review substantial changes that will occur even if emissions start to be curtailed early in the next century. He will show how these types of change will lead to a range of possible environmental impacts that will affect every region of the world.

Contact Dan Bedford of the Middlebury College geography department at 802-443-5210 or