The Causes and Consequences of Urban Heat Islands (Job Market Paper)
with Jonathan Colmer and John Voorheis
This paper studies the causes and consequences of urban heat islands. Combining new administrative data with a novel proxy for experienced temperature at the neighborhood scale, we show that a hot day increases mortality by six additional deaths per 100,000 for the elderly population living in neighborhoods with a high concentration of impervious surfaces, relative to the median. These patterns hold even within counties and cannot be explained by selection. Moreover, the increase in mortality among elderly Black Americans following a hot day is three times that of elderly White Americans, and half of this disparity can be attributed to Black individuals living in more impervious neighborhoods. We then present suggestive evidence that imperviousness is driven by density zoning policies, and document that the racial incidence of density is reflected in a long historical process since the Great Migration.
with Eleanor Krause
Estimating the value of improved environmental quality is of central interest to policymakers weighing the costs and benefits of environmental regulations. Under the standard hedonic valuation approach, researchers estimate the demand for environmental improvements from changes in housing prices. However, in a general equilibrium setting with elastic housing supply, amenity improvements may yield an expansion of the housing market (the ‘quantity’ effect), muting the capitalization of the amenity into housing prices (the ‘price’ effect), such that inferring benefits solely from price changes underestimates the true willingness-to-pay. We demonstrate how the elasticity of the local housing market affects valuations of amenity changes in the context of local air quality improvements induced by the Clean Air Act’s PM2.5 standards. We present consistent empirical evidence that the price capitalization of air quality improvements is substantially lower in places with more elastic housing markets, as increased demand is absorbed by expansions in housing supply. We present a model of spatial equilibrium of local prices, populations, and wages as functions of local amenities. Estimates from the model suggest that willingness-to-pay for air quality improvements are larger than the those produced by the standard hedonic approach.
Individual-Level Heat Disparities in the United States
with Jonathan Colmer and John Voorheis (draft available upon request)
Temperatures can vary substantially over short distances due to differences in land cover - a phenomenon known as the urban heat island effect. Little is known, however, about how the distribution of surface temperatures varies across individuals, how this has evolved over time, or the underlying drivers of disparities. Combining 20 years of high-resolution satellite-derived land surface temperature data, measured over 9 billion cells, with new individual-level data containing detailed demographic, residential, and economic information for every citizen and permanent resident of the contiguous United States between 2000 and 2019 (~6 billion individual-level observations), we provide the most comprehensive and systematic evaluation of surface temperature disparities to date. We document that within the same commuting-zone, Non-Hispanic Black individuals are exposed to higher surface temperatures than Non-Hispanic White individuals at every percentile of the income distribution. This pattern is stable over time and space. We show that individual economic circumstances can account for approximately 30 percent of the Black-White temperature gap, providing suggestive evidence that race rather than class is more important in determining heat disparities in the United States.