Abstract

We modeled the effects of increasing CO₂ and climate on net carbon storage in terrestrial ecosystems of the conterminous U.S. for the period 1895-1993 using new, detailed historical climate information. For the period 1980-1993, results from an ensemble of three models agree within 25%, simulating a land carbon sink from CO₂ and climate effects of 0.08 Gt C per year. The best estimates of the total sink from inventory data are approximately three times larger (~0.3 Gt C per year), suggesting that processes such as regrowth on abandoned agricultural land or in forests harvested before 1980 have effects as large or larger than the direct effects of CO₂ and climate. The modeled sink varies by ~100% from year-to-year as a result of climate variability, suggesting that any future policy or management measures based on estimates of net carbon storage must take this high variability into account. Recent published estimates of a nearly 2 Gt sink in the U.S. are in conflict with ecological process models and forest inventory-based techniques.

HOME PAGE   | CV MAIN PAGE  | CV  PUBLICATION INDEX  |ECOLOGICAL RESEARCH OVERVIEW  |  CLIMATE RESEARCH OVERVIEW