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Atmospheric CO2 levels and rising oceans
By Drs. Robert & Sonia Vogl
President and Vice President
Illinois Renewable Energy Association
Since the 1970s, scientists have been concerned about rising CO2 levels and the potential impact on the earth’s climate. By 1990, as the arctic showed signs of warming, questions were raised about what was happening with the Greenland ice sheet: Was it melting? If it were melting, at what rate, and what impact would this have on sea levels and human well-being? The potential effects were considered serious enough to warrant a research project to better understand the most likely outcomes. If the entire Greenland ice sheet were to melt, the sea level could rise by 23 feet. With nearly one-third of the world’s population living along coastal areas, a rapid change would have major adverse consequences.
Anders Carlson, a glacial geologist at the University of Wisconsin-Madison, is actively researching the Greenland ice sheet. His presentation at this year’s Aug. 8-9 Illinois Renewable Energy and Sustainable Lifestyle Fair at Ogle County Fairgrounds in Oregon, Ill., addressed the question of whether a rapid deglaciation of the Laurentide Ice Sheet provides an analogy for our future. The Laurentian ice mass at its peak reached Janesville, Wis., covered Chicago, and extended south to Shelbyville, Ill. As the climate warmed, the ice sheet melted back to an area around Quebec and Labrador, similar in size to the ice sheet now covering Greenland.
Research reveals a million-year record of existing ice cores. The cores consist of annual snowfalls, which include molecules of the atmosphere at the time the snow was deposited. From the cores we know that for the past 800,000 years, atmospheric CO2 levels have ranged from 180 ppm when glaciers were present to 280 ppm as glaciers melted.
Between 1850, with the arrival of industrialization, and 2005, another 100 ppm of CO2 had been added to the atmosphere. By 2009, CO2 increased to 385 ppm. If current trends continue, human activities could raise levels to between 550 ppm and 950 ppm by 2100. According to Carlson, since the original projections in the 1990s, CO2 actually added to the atmosphere has been on the high side of the estimates.
Considering the geologic evidence, at current atmospheric CO2 levels, existing sea levels should be more than 20 feet higher than they now are. Carlson likened the lag in ice melt and rising sea levels to the temperature of water in a teapot when the heat is first turned on. As CO2 levels rise, it could take from 50 to 100 years for the world’s average temperature to rise. It was assumed that changes in the ice sheets would be delayed by 1,000 years.
By combining older research tools with data from new techniques, Carlson has established that the Laurentide Ice Sheet retreated at the rate of 1 kilometer/year. At that rate, the sea level would have risen an average of 1 centimeter per year. Applying that change, by 2100, the sea level would be 1 meter higher than it is today. Such a rise would inundate the beach communities of Florida and the Gulf Coast, New Orleans would be flooded, and New York City would struggle with higher sea levels and subsequent storm surges.
The original projections of rising CO2 levels and their impact on sea levels only anticipated a sea level rise of 37 to 40 centimeters by 2100. According to Carlson, whether these long-term trends continue to accelerate will be determined by actions humans take to curtail the release of greenhouse gases to the atmosphere.
Drs. Robert and Sonia Vogl are founders and officers of the Illinois Renewable Energy Association (IREA) and coordinate the annual Renewable Energy and Sustainable Lifestyle Fair. The Vogls and the IREA are members of the Environmental Hall of Fame. Dr. Robert Vogl is vice president of Freedom Field, and Dr. Sonia Vogl is a member of Freedom Field’s Executive Committee. The Vogls consult on energy efficiency, renewable energy and green building. They have 3.2 kW of PV and a 1 kW wind generator at their home. Forty acres of their 180-acre home farm are in ecological restorations. They are active in preserving natural areas and are retired professors from Northern Illinois University. E-mail firstname.lastname@example.org.
From the September 9-15, 2009 issue