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Atmospheric Carbon Dioxide Measurement? That's Sooo Corny

Each year in the Environment chapter of the World Almanac, we present the annual atmospheric concentration of carbon dioxide (for 2007, it’s on page 284). We get that information from the Carbon Dioxide Information Analysis Center, which is part of the Department of Energy. Pre-1943 levels are derived from air bubbles in ice core samples taken in Antarctica, and later measurements are taken directly from the atmosphere. corn_crop.jpgSoon though, you may see us presenting CO2 levels taken from corn samples. That’s right, good ol’ fashioned corn, the vegetable that can do anything from feeding the world, to fueling our cars, to giving us a tasty treat at movie theaters.

Scientists from U.C. Irvine measured levels of carbon dioxide from fossil fuels in corn samples taken from 31 locations across the U.S. They chose corn because it’s grown pretty much everywhere, and the carbon in it is collected during a single growing season (so it's just the carbon from the most recent growing season, and not seasons past). CO2 from the burning of fossil fuels doesn’t contain any radiocarbons, so the scientists can easily tell if the carbon dioxide came from fossil fuels or from natural sources (veeeery C.S.I.-type stuff). By measuring the corn, the scientists were able to accurately tell which areas of the U.S. had highest concentrations of fossil-fuel-derived carbon dioxide. The highest levels were in California, Maryland, Ohio, Pennsylvania, and West Virginia. The lowest concentrations were in Colorado, Idaho, and New Mexico--because, as scientists found, the Rocky Mountains act as a sort of CO2 barrier.

There are lots of ways to measure CO2 in the atmosphere but this method may provide a cost-effective complement to other methods. If anything, it just goes to show that whatever is in the air can eventually end up in our popcorn.

Press release:Scientists map air pollution using corn grown in U.S. fields (U.C. Irvine)
Map: CO2 concentrations in the U.S. (Red areas have the highest, blue areas have the lowest)
Abstract: Regional patterns of radiocarbon and fossil fuel-derived CO2 in surface air across North America (Geophysical Research Letters, January 23, 2007)

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This page contains a single entry from the blog posted on January 24, 2007 2:00 PM.

The previous post in this blog was 2007 State of the Union (and Presidential Tag Cloud Revisited).

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