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 worlds
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
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
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 worlds
ecosystems more efficiently, we need to understand the system better."
- 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
- 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
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