Environmental Justice Viewed From Outer Space: How Does Growing Income Inequality Affect the Distribution of Pollution Exposure? (Job Market Paper)
Abstract: Economic inequality has increased dramatically in the United States since the 1970s, but little is known about what environmental effects this rising inequality might produce. This analysis explores how rising income inequality affects the distribution of exposure to NOx (a harmful pollutant) by combining newly available data with a new (to this literature) identification strategy. Novel high-resolution remote sensing data from NASA’s Aura satellite is used to measure exposure to NOx within U.S. metropolitan areas over the period 2005-2011. A simulated instrumental variable identification strategy shows that increasing income inequality within metropolitan areas has led to a decrease in the average level of pollution exposure, but has also increased both environmental inequality and the gap in pollution exposure between blacks and whites. These results seem to be mediated by the political process—increased income inequality has a positive effect on the pro-environmental voting records of US senators.
Unequal Incomes, Ideology and Gridlock: How Rising Inequality Increases Political Polarization (with Nolan McCarty and Boris Shor)
Abstract: Income inequality and political polarization have both increased dramatically in the United States over the last several decades. A small but growing literature has suggested that these two phenomena may be related and mutually reinforcing: income inequality leads to political polarization, and the gridlock induced by polarization reduces the ability of politicians to alleviate rising inequality. Scholars, however, have not credibly identified the causal relationships. Using newly available data on polarization in state legislatures and state-level income inequality, we extend previous analyses to the US state level. Employing a relatively underutilized instrumental variables identification strategy allows us to obtain the first credible causal estimates of the effect of inequality on polarization within states. We find that income inequality has a large, positive and statistically significant effect on political polarization. Economic inequality appears to cause state Democratic parties to become more liberal. Inequality, however, moves state legislatures to the right overall. Such findings suggest that the effect of income inequality impacts polarization by replacing moderate Democratic legislators with Republicans.
State and Metropolitan Area Income Inequality in the United States: Trends and Determinants, 1968-2012
Abstract: This study produces a new dataset of income inequality measures, within both US States and MSAs, covering the period 1968-2012. These measures adjust for Census Bureau topcoding and potential under-reporting of top incomes in the public-use CPS by modeling the tail of the size-adjusted household income distribution as following a Generalized Beta II distribution. We further develop a novel semi-parametric bootstrap method for inference on changes in inequality measures. By examining the entire Lorenz curve, we find that while the observed increase in inequality is consistent with an increase in top income shares, the losses are not uniformly distributed across the bottom of the distribution - the bottom half of the distribution bears the brunt of the losses in income share, while the top quartile is actually relatively better off. We conclude that de-unionization is the strongest candidate explanation for the changes in inequality within the bottom 99%, while changes in innovativeness may be important for explaining the changes in top incomes.
Trends in Environmental Inequality in the United States: Evidence from Satellite and Ground Monitor Data
Abstract: Using positive and normative tools common in the study of the distribution of income, we examine trends in and determinants of environmental inequality in the United States. Using data from EPA monitoring stations and the multinational Aura satellite, we obtain several findings. Average exposure to ozone and nitrogen dioxide have decreased since 1990, as has the degree of inequality in exposure. Pollution exposure inequality is highly correlated with demographic factors in any cross-section, but a majority of the change in environmental inequality is not explained by changes in demographics, but is rather at least partially the result of environmental policy.
Income Inequality and Carbon Emissions: Evidence from State-level Data
Abstract: The literature on Environmental Kuznets curves has argued that there is a non-linear relationship between income inequality and the level of carbon emissions. There is however conflicting empirical evidence as to whether this relationship is positive, negative or nonexistent, and there is no evidence that any relationship is causal. We use State-level data on carbon emissions and recently available data on State-level income inequality to estimate the causal effect of inequality on emissions using an instrumental variables identification strategy. We find that increases in income inequality lead to decreases in emissions, especially in the industrial and electricity generating sectors. This suggests that there may be a trade-off between addressing climate change and addressing rising income inequality.
"New Study Reveals Income Inequality Is the Real Reason American Politics Is So Broken"
Policy Mic, October 7, 2015
"These political scientists may have just discovered why U.S. politics are a disaster"
Washington Post, October 7, 2015
"What If All Politics is National?"
New York Times, September 30, 2015
"A New Insight Into Economic Inequality and Governence"
Equitable Growth, September 21, 2015
"How Rising Inequality Increases Political Polarization"
Economist's View, September 9, 2015
"This Map Will Show You The Staggering Growth In Income Inequality in the Last 40 Years"
Huffington Post, September 20, 2013
"Watch The Growth of U.S. Income Inequality With This Animated Map"
Washington Post, September 19, 2013
"State Inequality Visualizations"
Economist's View, September 19, 2013