Using remote sensing to quantify the additional climate benefits of California forest carbon offset projects.

Autor: Coffield SR; Department of Earth System Science, University of California, Irvine, Irvine, California, USA., Vo CD; Department of Earth System Science, University of California, Irvine, Irvine, California, USA., Wang JA; Department of Earth System Science, University of California, Irvine, Irvine, California, USA., Badgley G; Black Rock Forest, Cornwall, New York, USA.; CarbonPlan, San Francisco, California, USA., Goulden ML; Department of Earth System Science, University of California, Irvine, Irvine, California, USA.; Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, USA., Cullenward D; CarbonPlan, San Francisco, California, USA.; Institute for Carbon Removal Law and Policy, American University, Washington, District of Columbia, USA., Anderegg WRL; School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA., Randerson JT; Department of Earth System Science, University of California, Irvine, Irvine, California, USA.
Jazyk: angličtina
Zdroj: Global change biology [Glob Chang Biol] 2022 Nov; Vol. 28 (22), pp. 6789-6806. Date of Electronic Publication: 2022 Sep 12.
DOI: 10.1111/gcb.16380
Abstrakt: Nature-based climate solutions are a vital component of many climate mitigation strategies, including California's, which aims to achieve carbon neutrality by 2045. Most carbon offsets in California's cap-and-trade program come from improved forest management (IFM) projects. Since 2012, various landowners have set up IFM projects following the California Air Resources Board's IFM protocol. As many of these projects approach their 10th year, we now have the opportunity to assess their effectiveness, identify best practices, and suggest improvements toward future protocol revisions. In this study, we used remote sensing-based datasets to evaluate the carbon trends and harvest histories of 37 IFM projects in California. Despite some current limitations and biases, these datasets can be used to quantify carbon accumulation and harvest rates in offset project lands relative to nearby similar "control" lands before and after the projects began. Five lines of evidence suggest that the carbon accumulated in offset projects to date has generally not been additional to what might have otherwise occurred: (1) most forests in northwestern California have been accumulating carbon since at least the mid-1980s and continue to accumulate carbon, whether enrolled in offset projects or not; (2) harvest rates were high in large timber company project lands before IFM initiation, suggesting they are earning carbon credits for forests in recovery; (3) projects are often located on lands with higher densities of low-timber-value species; (4) carbon accumulation rates have not yet increased on lands that enroll as offset projects, relative to their pre-enrollment levels; and (5) harvest rates have not decreased on most project lands since offset project initiation. These patterns suggest that the current protocol should be improved to robustly measure and reward additionality. In general, our framework of geospatial analyses offers an important and independent means to evaluate the effectiveness of the carbon offsets program, especially as these data products continue improving and as offsets receive attention as a climate mitigation strategy.
(© 2022 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
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