Recent Publications
The Effectiveness of Financial Work Incentives in DI and SSI: Lessons from Other Transfer Programs
in Disability, Work and Cash Benefts, edited by Jerry Mashaw, Virginia Reno, Richard Burkhauser, and Monroe Berkowitz. Upjohn: Kalamazoo, Michigan, 1996, 189-222. (with Robert Moffitt)
Welfare Transfers in Two-Parent Families
Econometrica, Volume 64 No. 2, 295-332, March 1996
Has the Decline in Benefits Shortened Welfare Spells?
American Economic Review, Volume 84 No. 2, 43- 48, 1994. (with Thomas MaCurdy)
Systematic over-crediting in California’s forest carbon offsets program
Grayson Badgley, Jeremy Freeman, Joseph J. Hamman, Barbara Haya, Anna T. Trugman, William R.L. Anderegg, & Danny Cullenward (submitted to PNAS), https://doi.org/10.1101/2021.04.28.441870
Carbon offsets are widely used by individuals, corporations, and governments to mitigate their greenhouse gas emissions on the assumption that offsets reflect equivalent climate benefits achieved elsewhere. These climate-equivalence claims depend on offsets providing “additional” climate benefits beyond what would have happened, counterfactually, without the offsets project. Here, we evaluate the design of California’s prominent forest carbon offsets program and demonstrate that its climate-equivalence claims fall far short on the basis of directly observable evidence. By design, California’s program awards large volumes of offset credits to forest projects with carbon stocks that exceed regional averages. This paradigm allows for adverse selection, which could occur if project developers preferentially select forests that are ecologically distinct from unrepresentative regional averages. By digitizing and analyzing comprehensive offset project records alongside detailed forest inventory data, we provide direct evidence that comparing projects against coarse regional carbon averages has led to systematic over-crediting of 30.0 million tCO2e (90% CI: 20.5 to 38.6 million tCO2e) or 29.4% of the credits we analyzed (90% CI: 20.1 to 37.8%). These excess credits are worth an estimated $410 million (90% CI: $280 to $528 million) at recent market prices. Rather than improve forest management to store additional carbon, California’s offsets program creates incentives to generate offset credits that do not reflect real climate benefits.