Portrait of Peter O'Brien

Peter O'Brien

Ph.D. Candidate, Agricultural & Resource Economics
University of California, Davis

I am an applied economist working at the intersection of environmental economics, international trade, and agricultural economics. My research examines how trade shapes the environmental footprint of our food system. I combine causal inference methods and economic modeling with remotely sensed data and machine learning to study these changes at scale.

I am on the job market in the 2026–2027 academic year and can be reached at paobrien@ucdavis.edu.

Research

Job Market Paper

Feeding the Export Boom: Technological Change and Land Use in Brazil's Beef Industry

Latest version (PDF)

Abstract. Beef is among the most land- and emissions-intensive foods. In Brazil, expanding agricultural production has historically driven deforestation across carbon-rich ecosystems, including the Amazon. Rapid growth in beef exports raises concerns about further land conversion, yet access to foreign markets may also encourage agricultural intensification, or the adoption of technologies that reduce land requirements per unit of output. Because this intensification is difficult to observe, I use satellite imagery and deep learning to build a novel panel of Brazilian feedlots, facilities where cattle are produced in confinement rather than grazing on pasture. I combine this panel with records of processing-plant authorizations to study the effects of Brazil's beef export boom to China. I exploit variation in the timing of plant authorizations and regions' exposure to newly authorized plants and find that greater export exposure substantially increased feedlot entry and total capacity. Holding current beef production fixed, replacing this China-induced intensive production with traditional, grazing-based systems would require approximately 1.29 million additional hectares of pasture. This would put 169 MtCO2 of carbon stocks at risk, an amount greater than one-third of Brazil's annual emissions, underscoring how trade-induced technological change can shape the environmental consequences of agricultural production.

Work in Progress

Does Eating Local Reduce Emissions?

with Levi Crews, Ishan Nath, Milan Quentel, and James Sayre

Draft in progress.

Abstract. This paper examines the conventional wisdom that promoting the consumption of locally produced food reduces greenhouse gas emissions. We first quantify the consequences of an individual consumer's food-sourcing decisions for the carbon footprint of their diet. We combine spatially explicit estimates of production emissions for 46 agricultural products with a model of global transportation and processing networks, allowing us to calculate the average supply-chain emissions associated with sourcing each product from alternative locations worldwide. We show that the spatial variation in emissions from producing food products is large relative to the emissions from shipping them, and in many cases, consumers minimize emissions by purchasing food from a non-local source. We then use a quantitative spatial model to investigate the aggregate emissions implications of global trade in agricultural goods.

Publications

Do California's Cattle Emit Less Carbon Than We Think?

ARE Update, 2025 · with James Sayre