Climate change science : observations on the potential role of carbon offsets in climate change legislation : testimony before the Subcommittee on Energy and Environment, Committee on Science and Technology, House of Representatives

Climate Change Clearinghouse2009PDFResearch PaperStephenson, JohnUnited States. Congress. House. Committee on Science and Technology (2007). Subcommittee on Energy and EnvironmentUnited States. Government Accountability OfficeUnited States. Government Accountability OfficeUnited StatesClimate changeGlobal warmingGreenhouse effectCarbon taxesEmissions tradingLaws and legislationPollution controlCost effectivenessClimate changesGreenhouse gasesCarbon dioxide mitigationGreenhouse gas mitigationLaw and legislationGAO-09-456TIn an August 2008 report, GAO identified four primary challenges related to the United States voluntary carbon offset market. First, the concept of a carbon offset is complicated because offsets can involve different activities, definitions, greenhouse gases, and timeframes for measurement. Second, ensuring the credibility of offsets is challenging because there are many ways to determine whether a project is additional to a business-as-usual baseline, and inherent uncertainty exists in measuring emissions reductions relative to such a baseline. Related to this, the use of multiple quality assurance mechanisms with varying requirements may raise questions about whether offsets are fully fungible\u2014interchangeable and of comparable quality. Third, including offsets in regulatory programs to limit greenhouse gas emissions could result in environmental and economic tradeoffs. For example offsets could lower the cost of complying with an emissions reduction policy, but this may delay on-site reductions by regulated entities. Fourth, offsets could compromise the environmental certainty of a regulatory program if offsets used for compliance lack credibility.109