For Immediate Release August 21, 2001	Contact: Peter Frenzen (360) 449-7835 peter.frenzen@esd112.k12.wa.us Terry Gerlach (360) 993-8916, tgerlach@usgs.gov

Geology Seminar and Guided Walk this Saturday at Mount St. Helens

Geochemist Terry Gerlach of the USGS, Cascades Volcano Observatory will discuss volcanoes as producers of carbon dioxide (CO2) gas and how they compare to human generated sources of this important greenhouse gas. The 25-minute slide talk will be Saturday, August 25th at 1 p.m. in the auditorium of the Johnston Ridge Observatory, Mount St. Helens National Volcanic Monument.

At 2:30 p.m., following the seminar, join an interpretive naturalist, the seminar speaker, and the Monument Scientist for a 2-hour, guided exploration of the debris avalanche on the 2.3-mile Hummocks Trail loop.

Admission to the Johnston Ridge Observatory is $3 for adults and $1 for children (ages 5 to 15). Children 4 and under are free. Multi-visitor center passes, which includes Coldwater Ridge Visitor Center and Mount St. Helens Visitor Center at Silver Lake, are also available for an additional charge (inquire at centers).

For more information about the Mount St. Helens National Volcanic Monument, visit our web site at www.fs.fed.us/gpnf/mshnvm.

Description of Saturday's presentation:

Volcanoes and Greenhouse Gases: Do Volcanoes Put Out as Much Carbon Dioxide as We Do?
Terry Gerlach, US Geological Survey, Cascades Volcano Observatory

The greenhouse gas carbon dioxide (CO2) is the most abundant gas (after water) emitted by volcanoes. Volcanologists estimate an annual global output of 200 million tons of volcanic CO2 per year. This natural source is balanced by natural processes that remove CO2 from the atmosphere-specifically by the weathering of rock into soil by atmospheric CO2 dissolved in rain and surface waters.

By comparison, human activities such as the burning of fossil fuels and deforestation produce 130 times more CO2 than all the world's volcanoes put together (adding 26,000 million tons of CO2 to the atmosphere each year, the equivalent of 8,000 Kilaueas (Hawaii's most active volcano). This comparison suggests humans are producing CO2 at a rate unprecedented in a geological history stretching back many millions of years. Clearly, there is need to think seriously about the implications of human CO2 emissions and to consider how current energy policy and land use practices may impact our collective future.

A complete list of our summer geology seminar series (both past and future).

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Gifford Pinchot National Forest
Revised: 21 August 2001