Ryan Abman

Biography

Published Work

• 2026

  "The Limits of Cross-Border Environmental Policies: Trade Diversion as Leakage." With Hattie Jenkins and Clark Lundberg. Journal of Environmental Economics and Management.

  Abstract

  Global environmental externalities are one of the most pressing policy challenges of the modern era. Unilateral policy options to address global externalities are limited, however, by sovereignty and a general difficulty in achieving environmental objectives across national borders. We study an emerging trade policy tool used in cross-border environmental policies—environmental standards for imports—using a European Union program aimed at mitigating illegal timber harvesting in tropical timber exporting countries. Through bilateral agreements with partner countries, the program established de facto import restrictions through supply chain transparency and certification requirements on forest products. We find that the policy led to a diversion of partner country exports away from the EU towards other markets, particularly in Asia, and had no discernible impact on reducing forest loss. Our findings highlight the role that trade diversion can play as a leakage mechanism in such cross-border environmental policies.

• 2025

  "Water, Dust, and Environmental Justice: The Case of Agricultural Water Diversions." With Eric C. Edwards and Danae Hernandez-Cortes. American Journal of Agricultural Economics, Vol. 107, Issue 4, pp. 1041–1058.

  Abstract KPBS CNS

  Water diversions for agriculture reduce ecosystem services provided by saline lakes around the world. Exposed lakebed surfaces are major sources of dust emissions that may exacerbate existing environmental inequities. This paper studies the effects of water diversions and their impacts on particulate pollution arising from reduced inflows to the Salton Sea in California via a spatially explicit particle transport model and changing lakebed exposure. We demonstrate that lakebed dust emissions increased ambient concentrations and worsened environmental inequalities, with historically disadvantaged communities receiving a disproportionate increase in pollution. Water diversion decisions are often determined by political processes; our findings demonstrate the need for distributional analysis of such decisions to ensure equitable compensation.

• 2024

  "The Effectiveness of Environmental Provisions in Regional Trade Agreements." With Clark Lundberg and Michele Ruta. Journal of the European Economic Association, Vol. 22, Issue 6, pp. 2507–2548.

  Abstract

  Trade liberalization can spur environmental degradation. Concerns over these adverse impacts have led to a debate over the need for environmental provisions in regional trade agreements (RTAs); however, the effectiveness of such provisions is unknown. In this paper, we provide new plausibly causal evidence that environmental provisions are effective in limiting deforestation following the entry into force of RTAs. We exploit high resolution, satellite-derived estimates of deforestation, and identify the content of RTAs using a new dataset with detailed information on individual provisions. Accounting for the potential endogeneity of environmental provisions in RTAs, we find that the inclusion of specific provisions aimed at protecting forests and/or biodiversity almost entirely offsets the net increases in forest loss observed in similar RTAs without such provisions. The effects are particularly strong in tropical, developing countries with greater biodiversity. The inclusion of these provisions limits agricultural expansion and agricultural trade.

• 2024

  "Contracting, Market Access and Deforestation." With Clark Lundberg. Journal of Development Economics, Vol. 168.

  Abstract

  We study the impacts of market access on forest loss in Ghana through a program designed to increase smallholder participation in oil palm commodity markets. Improved market access is facilitated through production contracts in which smallholders receive credit to establish production, a guaranteed price and quantity for the contract duration, and output pickup at the village. Using a variety of difference-in-differences approaches, we find substantial increases in forest loss in targeted villages following the introduction of the contracting program. The findings suggest that the ecological impacts of reforms to market access may be sizeable.

• 2023

  "Resource Development and Governance Declines: The Case of the Chad–Cameroon Petroleum Pipeline." With Gabrial Longbrake. Energy Economics, Vol. 117.

  Abstract

  In this paper, we study the effects of the Chad–Cameroon Petroleum Development and Pipeline Project that allowed Chad to begin producing and exporting oil. The project was financed under heavy restrictions by the World Bank in an attempt to avert the resource curse. The majority of revenue from the resource was to be directed back into development programs with minimal government discretion. Using synthetic control matching and synthetic difference in differences, we find that oil production had immediate and persistent negative impacts on the quality of governance, increased GDP per capita, but had little lasting effects on measured development outcomes such as infant mortality and health spending. Our findings offer new empirical evidence for the political resource curse and suggest that the World Bank's experiment to impose rules over management of resource rents was not sufficient to ensure widespread benefits from natural-resource wealth.

• 2022

  "Maize Price Volatility and Deforestation." With Clark Lundberg. American Journal of Agricultural Economics, Vol. 104, Issue 2, pp. 693–716.

  Abstract

  We develop a model of deforestation using a real option on agricultural land conversion and establish an important link between agricultural commodity price volatility and forest loss. Higher price volatility of staple commodities increases incentives to delay land conversion and is associated with lower levels of deforestation. Using satellite-derived estimates of local deforestation and high-frequency local maize prices across a panel of market catchments across 26 countries in sub-Saharan Africa, we find strong empirical evidence that maize price volatility is negatively associated with forest loss. Our findings are driven by catchments in biomes that are relatively well-suited to maize production. Instrumenting for changes in price levels and price volatility with spatially explicit temperature and rainfall anomalies yields results consistent with our main approach. The findings highlight important tensions between agricultural price stabilization policies, conservation efforts, and environmental externalities.

• 2022

  "Border Walls and Crime: Evidence from the Secure Fence Act." With Hisham Foad. Eastern Economic Journal, Vol. 48, Issue 2, pp. 167–197.

  Abstract 🏆 Eckstein Award — Best 2021–22 Paper The Crime Report CATO Research Brief

  Despite a lack of rigorous empirical evidence, reduced crime is often touted as a potential benefit in the debate over increasing border infrastructure (i.e., border walls). This paper examines the effect of the Secure Fence Act of 2006, which led to unprecedented barrier construction along the US–Mexico border, on local crime using geospatial data on dates and locations of border wall construction. Synthetic control estimates across twelve border counties find no systematic evidence that border infrastructure reduced property or violent crime rates in the counties in which it was built. Further analysis using matched panel models indicates no effect on property crime rates and that observed declines in violent crime rates precede barrier construction, not the other way around. Taken together, this paper finds that potential crime reductions are not a compelling argument toward the benefits of expanding border infrastructure.

• 2020

  "Agricultural Productivity and Deforestation: Evidence from Input Subsidies and Ethnic Favoritism in Malawi." With Conor Carney. Journal of Environmental Economics and Management, Vol. 103.

  Abstract

  This paper studies the underlying relationship between agricultural productivity and deforestation by analyzing the impacts of a large fertilizer and seed subsidy program in Malawi. In the absence of well-defined subsidy eligibility criteria, we demonstrate that areas with a high proportion of individuals of the same ethnicity as the president received more subsidized fertilizer and deforested less compared to areas with other predominant ethnicities. We provide evidence that subsidized fertilizer increased yields and reduced pressure to expand agriculture and that the findings are not confounded by increases in public sector employment or other public assistance programs. The results suggest that policies aimed at increasing small-scale agricultural productivity may have positive environmental spillovers.

• 2020

  "Land Rights, Agricultural Productivity, and Deforestation." With Conor Carney. Food Policy, Vol. 94.

  Abstract

  This paper studies the relationship between land tenure for smallholder agriculture and deforestation. We combine high resolution satellite data on deforestation with rich household and commune-level, biannual panel data from Vietnam. We study two margins of tenure security, whether a household has any land title (extensive) and the share of a household's land held in title (intensive). Using a household-fixed effects model, we find the increases in crop production and land investment associated with holding land title are driven by the intensive margin. We then aggregate the survey data to the commune-level and find evidence that marginal increases in extensive tenure (share of households with any land title) increase deforestation holding constant the average intensive tenure (average share of land held in tenure among those with land title). We find some evidence that increasing the intensive margin of tenure (holding constant the extensive tenure) decreases deforestation. These results present a more nuanced view of the tenure-deforestation relationship than is prevalent in the existing literature.

• 2020

  "Does Free Trade Increase Deforestation? The Effects of Regional Trade Agreements." With Clark Lundberg. Journal of the Association of Environmental and Resource Economists, Vol. 7, No. 1, pp. 35–72.

  Abstract

  This paper provides new, global evidence on the relationship between trade liberalization and deforestation. Using event studies around the enactment of regional trade agreements (RTAs) on a panel of 189 countries from 2001 to 2012, we find a large and statistically significant increase in deforestation over the 3 years following the enactment of an RTA, which coincides with an increase in agricultural land conversion. The findings are robust to a variety of controls and fixed effects. The results on deforestation and agricultural land expansion are driven by developing countries in the tropics, suggesting that trade liberalization not only increases net deforestation but may also shift deforestation into ecologically sensitive locations. We find no evidence that these effects are driven by increases in timber harvest. Our results suggest that trade liberalization efforts should be accompanied by policies to direct agricultural land expansion away from forests and sensitive habitat regions.

• 2018

  "Rule of Law and Avoided Deforestation from Protected Areas." Ecological Economics, Vol. 146, pp. 282–289.

  Abstract

  Global efforts to protect biodiversity and slow deforestation rely heavily on the establishment of protected areas; land set aside that cannot be deforested or developed. This paper studies the macro-level relationship between rule of law and variation in avoided deforestation from protected areas. Using recent global satellite data from 2000 to 2012, I estimate the country-level avoided deforestation of protected areas established in this period via nearest-neighbor matching. I then use weighted least-squares regressions to explain country-level variation in estimated avoided deforestation as a function of a country's governance characteristics as well as other country-level controls. Across 71 countries in this study period, protected areas were more effective in countries with higher levels of corruption control and protection of property rights, protected areas were more effective in more democratic countries, and there appears to be no relationship between political stability and avoided deforestation from protected areas.

• 2013

  "The Underground Economy of Fake Antivirus Software." With Brett Stone-Gross, Richard A. Kemmerer, Christopher Kruegel, Douglas G. Steigerwald, and Giovanni Vigna. Economics of Information Security and Privacy III.

  Press: The Economist · Krebs on Security