Implications for Global Climate
Compared to other ecosystems, the boreal forest responds relatively quickly to changes in climate. Moreover, analysis of meteorological trends from 1961-90 shows that temperature increases are occurring most rapidly over the interiors of continents at high latitudes (43°N to 65°N)–precisely the location of the boreal forest. In the last 40 years, average temperatures have increased over these regions by as much as 1.25°C per decade (Sellers et al. 1997). If the world’s missing carbon is in fact being stored within the boreal forest, and if the present warming trend is turning the boreal forest into a source of carbon, then there could be a significant increase in the rate of carbon build-up in the atmosphere. Scientists fear that by the year 2100 the amount of carbon dioxide in the atmosphere might actually double pre-industrial levels (Wofsy 1999)–to more than 560 parts per million (the 1990 level was 353 parts per million).

In their Science article, Wofsy and his colleagues note that the global mean temperature is predicted to increase by about 2°C by the year 2100. They state that warming of this magnitude would likely completely thaw the deep layers of frozen boreal soil at the old black spruce site and, as they dry, significantly increase the decomposition of the carbon there. If this trend occurs on a large scale across the boreal ecosystem, the decomposing boreal soils could significantly accelerate the rate of rise of carbon dioxide levels in the atmosphere.

Today, Wofsy, Hall, and their BOREAS colleagues can only speculate what will happen to the boreal ecosystem over the next century. But their hope is that as they continue to collect more data and refine their models, they can one day solve the mystery of the missing carbon and accurately predict what future levels of carbon dioxide will be. "How can we manage the forests for economic return and still keep carbon out of the atmosphere?" Wofsy asks rhetorically. "If we are to have any hope of managing the world’s ecosystems more efficiently, we need to understand the system better."

• References
• Sellers, P.J., F.G. Hall, R.D. Kelly, A. Black, D. Baldocchi, J. Berry, M. Ryan, K.J. Ranson, P.M. Crill, D.P. Lettenmaier, H. Margolis, J. Cihlar, J. Newcomer, D. Fitzjarrald, P.G. Jarvis, S.T. Gower, D. Halliwell, D. Williams, B. Goodison, D.E. Wickland, and F.E. Guertin, 1997: BOREAS in 1997: Experiment Overview, Scientific Results and Future Directions, Journal of Geophysical Research, 102, pp. 28731-28770.
• Hall, Forrest G. Personal Interview, 1999.
• Goulden, M.L., S.C. Wofsy, J.W. Harden, S.E. Trumbore, P.M. Crill, S.T. Gower, T. Fries, B.C. Daube, S.-M. Fan, D.J. Sutton, A. Bazzaz, and J.W. Munger, 1998: Sensitivity of Boreal Forest Carbon Balance to Soil Thaw, Science, 279, pp. 214-217.
• Wofsy, Steven C. Personal Interview, 1999.

Findings from One BOREAS Study Site

 

Work on the ground is a necessary component of the scientific process, even at NASA. These researchers are collecting samples of vegetation for the BOREAS archive. (Photograph courtesy BOREAS project)