 by David Herring and Robert Kannenberg April 28, 1999 |
Boreal Ecosystem Series |
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| Scientists estimate that between 1 and 2 billion metric tons of carbon per year are "missing" from the global carbon budget. Or, more precisely, they cannot account for the location of between 15 and 30 percent of the carbon released into the atmosphere each year from fossil fuel burning (Sellers et al. 1997). Worldwide, humans annually release about 7 billion tons of carbon. Of that amount, 3 billion tons remain in the atmosphere, 2 billion tons are absorbed into the ocean, and…the rest? Scientists assume land vegetation absorbs the rest, but they don’t know exactly where or how much. |
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The main motivation for studying Earth’s global carbon cycle is to enable scientists to predict future levels of carbon dioxide in the atmosphere. According to Steven C. Wofsy, an environmental scientist at Harvard University, the ability to predict carbon dioxide levels is important if Earth scientists are to answer fundamental questions like how much will global temperatures rise over time, and how will this affect other aspects of Earth’s climate? "Are those 2 billion tons of carbon missing permanently, or temporarily?" Wofsy asks. "You’re at a loss
to predict if you don’t know why the carbon is disappearing and if it will stay gone." |
Ecologist Joe Berry checking instruments at the top of a tower in Saskatchewan, Canada. He is surrounded by 120-year-old black spruce, one of the predominant trees in the boreal forest. (Photograph courtesy BOREAS project) |
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The circumpolar range of the boreal forest. From Hare and Ritchie (1972) (Map courtesy BOREAS project) |
In a concerted
effort to solve the mystery of the missing carbon, NASA led an interdisciplinary Boreal
Ecosystem-Atmosphere Study (BOREAS) from 1994-97 that spanned two Canadian provinces. Wofsy, along with
members of 85 other science teams from five nations, participated in the investigation. Their prime
suspect was the boreal forest. Named after Boreas, Greek god of the north wind,boreal refers to
the mostly evergreen forest that encircles the Earth at high northern latitudes–between
43°N-65°N–occupying between 16 to 20 million square kilometers of the Earth’s land surface. Could this
cold, mostly coniferous ecosystem be the culprit?
Some Important Clues