Global ChangeIntroduction:Global Change is a new multidisciplinary science that seeks to understand the various ways in which the environment is altered by human activities. The mechanisms of change are called anthropogenic forcing and are usually involved in weathering or changes in land use. The atmosphere is altered by the addition of many chemicals including carbon dioxide, nitrogen oxides, sulfur compounds, halogenated compounds and various aerosols. Land use changes include habitat fragmentation, conversion to agricultural uses, and biome conversion from introduced exotic species. The continuing expansion of the human population places increasing pressure on ecosystem services (Cairns, 1996). Ecosystem services are those benefits that humans derive from the natural world, including air and water with a composition that promotes health, soil and nutrients in which to grow food, plants to convert sunlight into energy, and an atmosphere which provides livable climatic conditions. Global change research attempts to quantify and understand these processes and how human activities can alter them. Current research programs are conducted by the National Science Foundation, the United Nations, the International Geosphere-Biosphere Project (Walker, 1994), the World Wildlife Fund for Nature, and many other nations and international organizations. Atmospheric Change Global Warming One of the most heated debates about global change is the possibility of global warming. The first hints of global warming came from carbon dioxide data from David Keeling's Mauna Loa Observatory that showed repeated annual fluctuations and a definite upward trend in atmospheric carbon dioxide concentrations (Graedel, 1993). Since then...... half of the document....../www.lib.utexas.edu:80:/Libs/PCL/Map_collection/Map_collection.html7. Sustainable development http://www.ulb.ac.be/ceese/sustvl.html8. Environment Today http://enviro.mond.org/9. National Biological Survey http://www.im.nbs.gov/10. University Corporation for Atmospheric Research http://www.unidata.ucar.edu/11. National Climate Data Center http://www.ncdc.noaa.gov/ncdc.html12. United Nations International Panel on Climate Change http://www.unep.ch/ipcc/ipcc-O.html13. Global Changes Master Directory http://www.gcmd.gsfc.nasa.gov/14. USDOE Carbon Dioxide Information Analysis Center http://cdiac.esd.ornl.gov/15. The Nature Conservancy http://www.tnc.org/16. EPA Global Warming Page http://www.epa.gov/globalwarming/home.htm17. United Nations Global Environment Outlook 1997 http://www.grid.unep.ch/geol/