Gas flaring, agricultural productivity and labor reallocation: Evidence from Nigeria
中文摘要
本文研究天然气放空燃烧——石油生产的副产品——对尼日利亚农业生产率的影响。研究使用覆盖2012–2018年的尼日利亚生活水平测量研究(LSMS)家庭面板数据，并结合油田月度放空燃烧量的地理编码数据，利用入户访谈时间的差异来评估收获季和播种季放空燃烧的影响。分析聚焦于石油生产集中的尼日利亚南部，并利用2010年的一项政策改革（《本地内容法》）——该改革增加了本地陆上石油活动，从而增加了放空燃烧。实证策略包括用以控制不可观测异质性的固定效应（家庭固定效应以及地区×月份×年份固定效应）、天气变量（降水和气温），以及采用全球油价变动与样本前期放空燃烧强度交互项的工具变量方法以处理内生性。主要结果变量为每公顷实际作物产量和劳动生产率（实际农业产出除以工日数）。研究发现，放空燃烧在收获季具有显著的负面影响，在雨季期间尤为明显，而在播种季的影响微乎其微。机制分析利用大气污染物的卫星数据，显示放空燃烧地区黑碳、二氧化硫和二氧化氮水平升高。稳健性检验表明，在考虑冲突、石油泄漏等各类混淆因素并进行安慰剂检验后，结果依然成立。本文丰富了关于空气污染对工人生产率和作物产量影响以及气候变化对农业影响的文献，并凸显了发展中国家减轻采掘业环境成本的政策需求。
Abstract
This paper investigates the impact of natural gas flaring—a byproduct of oil production—on agricultural productivity in Nigeria. Using a panel dataset of Nigerian households from the Living Standards Measurement Study (LSMS) spanning 2012–2018, combined with geocoded data on monthly gas flaring volumes from oil fields, the study employs variation in the timing of interview surveys to assess effects of gas flaring during harvest and planting seasons. The analysis focuses on southern Nigeria, where oil production is concentrated, and leverages a 2010 policy reform (Local Content Act) that increased local onshore oil activities and thus gas flaring. The empirical strategy includes fixed effects (household, and region-by-month-by-year) to control for unobserved heterogeneity, weather variables (precipitation and temperature), and an instrumental variable approach using global oil price changes interacted with pre-sample flaring intensity to address endogeneity. Key outcomes measured are real crop yield per hectare and labor productivity (real agricultural output divided by worker-days). The findings reveal significant negative effects during the harvest season, particularly in rainy periods, but minimal impacts during planting. Mechanisms are explored through satellite data on air pollutants, showing elevated levels of black carbon, sulfur dioxide, and nitrogen dioxide in flaring areas. Robustness checks confirm the results against various confounders like conflicts, oil spills, and placebo tests. The paper contributes to literature on the impact of air pollution on worker productivity and crop yields and climate change impacts on agriculture, highlighting policy needs to mitigate environmental costs from extractive industries in developing countries.