--- Mario Goveia <[EMAIL PROTECTED]> wrote: > >How do we deal with just Mount St. Helens, now >belching several years worth of man made greenhouse >gases into the atmosphere ever day. Try putting a >cork on that one small natural cause! Or the gases >produced by rotting vegetation worldwide or the >effects from evaporation from all bodies of water. >
The above statements are completely false. At Mount St. Helens the maximum measured emission rate of the greenhouse gas carbon dioxide is 22 kilotons per day. By contrast human activity involving expenditure of fossil fuels and land use produces a net output of 1,500,000 kilotons of this gas per day. These values are calculated from data obtained from the following scientific study: Harris, D.M., Sato, M., Casadevall, T.J., Rose, Jr., W.I., and Bornhorst, T.J., 1981, Emission rates of CO2 from plume measurements, in Lipman, P.W., and Mullineaux, D.R., (eds.), The 1980 eruptions of Mount St. Helens, Washington, U.S. Geological Survey Professional Paper 1250, p. 3-15. >From the transcript of a talk entitled "Volcanoes and Greenhouse Gases: Do Volcanoes Put Out as Much Carbon Dioxide as We Do?" given by Dr. Terry Gerlach of the U.S. Geological Survey and the Cascades Volcano Observatory, one of the world’s leading experts on volcanic emissions, I learned that human activities such as the burning of fossil fuels and deforestation produce 130 times more carbon dioxide than all the world's volcanoes put together. Human activity produces 26,000 million tons of carbon dioxide per year compared to 200 million tons produced by all the volcanoes combined. Furthermore, very powerful greenhouse gases such as hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride are not emitted at all by volcanoes or any other natural process. They increase only as a result of industrial pollution. The 20-year global warming potential of sulfur hexafluoride is 16,300 times greater than that of carbon dioxide. Before the industrial revolution there was no sulfur hexafluoride in the atmosphere. Now there is 4.2 parts per million of it. It can persist in the atmosphere with a lifetime of 3200 years, compared to carbon dioxide, which has an atmospheric lifetime of 50 to 200 years. Please see the following PDF document provided by the U.S. Environmental Protection Agency, entitled “Greenhouse Gases and Global Warming Potential Values”, for comparisons of greenhouse gases put out by natural and man-made processes: http://yosemite.epa.gov/oar/globalwarming.nsf/UniqueKeyLookup/SHSU5BUM9T/$File/ghg_gwp.pdf Here are the proper facts regarding rotting vegetation and natural bodies of water, excerpted from page 39 of a report of the Intergovernmental Panel on Climate Change, entitled "Science of Climate Change". "Before human activities began to dramatically increase carbon dioxide levels in the atmosphere, the amount of carbon dioxide emitted from natural sources closely matched the amount that was stored or absorbed through natural processes. For example, as forests grow, they absorb carbon dioxide from the atmosphere through photosynthesis; this carbon is then sequestered in wood, leaves, roots and soil. Some carbon is later released back to the atmosphere when leaves, roots and wood die and decay. Carbon dioxide also cycles through the ocean. Plankton living at the ocean's surface absorb carbon dioxide through photosynthesis. The plankton and animals that eat the plankton then die and fall to the bottom of the ocean. As they decay, carbon dioxide is released into the water and returns to the surface via ocean currents. As a result of these natural cycles, the amount of carbon dioxide in the air had changed very little for 10,000 years. But that balance has been upset by man. Since the Industrial Revolution, the burning of fossil fuels such as coal and oil has put about twice as much carbon dioxide into the atmosphere than is naturally removed by the oceans and forests. This has resulted in carbon dioxide levels building up in the atmosphere. Today, carbon dioxide levels are 30% higher than pre-industrial levels, higher than they have been in the last 420,000 years and are probably at the highest levels they have been in the past 20 million years. Studies of the Earth's climate history have shown that even small, natural changes in carbon dioxide levels were generally accompanied by significant shifts in the global average temperature. We have already experienced a 1°F increase in global temperature in the past century, and we can expect significant warming in the next century if we fail to act to decrease greenhouse gas emissions." Cheers, Santosh