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| Fig. 1: An example of the violent release of forest based carbon into the atmosphere. (Courtesy of the USDA. Source: Wikimedia Commons) |
For some, carbon offset projects present a beneficial a way to harness public support for climate change mitigation, as well as provide meaningful alternatives for corporations and governments to respond to increasing greenhouse gas emissions. Critics argue that carbon offset projects help only to shift the burden away from corporations for ever-growing carbon footprints, and often capitalize on projects that would have happened anyway. Here we will look at the efficacy of forest based carbon offset projects, and attempt to evaluate whether they are significant tools in lowering atmospheric carbon levels.
Atmospheric carbon dioxide forms the overwhelming majority of global greenhouse gas emissions, and for a long time has been known to play a major role in climate change. [1,2] A growing method of reducing net emissions is through carbon capture in forests, a tactic commissioned by United Nations Framework Convention Climate Change (FCCC). In the United States alone, forests absorb an estimated 200 million metric tons of carbon per year (200 Tg C/year), offsetting approximately 10% of US emissions. [3] Efforts to increase this number include: creation of new forests and reforestation; conserving existing forests through land use regulation; and expanding the carbon sequestering capacity of forests by increasing forest density. [4]
Carbon offset projects in general suffer from accounting issues and lack of international evaluation standards. Various governments have committed to reduce emissions through treaties such as the Kyoto Protocol or the Paris Agreement, and this has in part led to the formation of carbon-credit programs which attempt to use market forces to incentivize corporations or governments to lower or offset their carbon emissions. One of the major criticisms of carbon offset programs is that international standard regarding how to evaluate the total carbon sequestered by, for example, a forestry project, has not been universally agreed upon. As a result, several different competing standards have been established, which makes it difficult to agree on the true impact of such projects. [5]
In addition to accounting challenges, sequestering carbon in forests is an inherently risky practice, as sudden and volatile CO2 releases due to fire could setback years of effort. Fig. 1 shows an example of the dangers of forest-based carbon projects due to the potential for violent release of carbon into the atmosphere through fire. The amount of carbon released into the atmosphere from forest fires each year can be quite significant. Studies show that from 2002-2007 an estimated average of 2.1 Pg C was released each year from global fires. [6] This can be compared with the average global carbon emissions at 49.5 Pg C/year reported by IPCC for 2010. [7]
Carbon offset projects have the potential to be a significant part of global tactics to lower net CO2 emissions. Beyond the scientific factors involved in evaluating the efficacy of forest-based carbon offset projects, there are also social and political challenges. Whether land owners (governments included) can be incentivized to use their forests in this way is still unclear, and depends largely on the specifics of the region. [2] On top of this challenge, mismanagement can lead to fires and pests, which could jeopardize the stability of carbon sequestered in forests. Without an approach to ensure these risks are minimized, the potential that forests have in carbon-offset could go largely under-utilized.
[1] D. Schimel et al., "Radiative Forcing of Climate Change," in Climate Change 1995: The Science of Climate Change, ed. by J. T. Houghton et al. (Cambridge University Press, 1996), p. 65.
[2] "Climate Change Indicators in the United States 2016, Fourth Edition," U.S. Environmental Protection Agency, 2016.
[3] L. S. Fletcher, D. Kittredge Jr., and T. Stevens, "Forest Landowners' Willingness to Sell Carbon Credits: A Pilot Study," North. J. Appl. For. 26, 35 (2009).
[4] S. Brown et al., "Issues and Challenges for Forest-Based Carbon Offset Projects: A Case Study of the Noel Kempff Climate Action Project in Bolivia," Mitig. Adapt. Strat. Gl. 5, 99 (2000).
[5] A. Kollmuss, H. Zink, and C. Polycarp, "Making Sense of the Voluntary Carbon Market: A Comparison of Carbon Offset Standards," Stockholm Environment Institute, March 2008.
[6] G. R. van der Werf et al., "Global Fire Emissions and the Contribution of Deforestation, Savanna, Forest, Agricultural, and Peat Fires (1997-2009)," Atmos. Chem. Phys. 10, 11707 (2010).
[7] D. G. Victor et al., "Introductory Chapter," in Climate Change 2014: Mitigation of Climate Change, ed. by O. Edenhofer et al. (Cambridge University Press, 2014), p. 111.
