Temporal dynamics of selected terrestrial carbon pools. Annual progress report, June 5, 1981-June 4, 1982

The study assesses the temporal dynamics of resource utilization in forest and wetland ecosystems as it relates to global carbon storage or release. Results to date indicate that: (1) drainage of wetlands, which once functioned as carbon sinks, is causing a shift in carbon releases from the biosphere currently estimated to be around 0.2 x 10/sup 9/ tons per year. However, resource development plans suggest that tropical wetlands may form an increasing source over the next several decades; (2) intensified harvest is likely to convert US forests from a net carbon sink to a net source by the year 2010 or sooner. Plausible scenarios of biomass energy development suggest that forest utilization will intensify, lowering the total stored carbon. Whether similar trends will significantly affect the carbon balance in other temperate and tropical countries is under investigation; and (3) the carbon balance of the biosphere appears to be currently unstable, developing more unambiguously into a significant net source of atmospheric CO/sub 2/. Although uncertainties are still significant, updated estimates of annual change in 14 biospheric pools indicates a probable net biospheric release of 0.85 +- .30) x 10/sup 9/ tons in 1979, up from 0.39 (+- .20) x 10/sup 9/more » tons in 1965, an increase of 7.4% per year.« less