WORKS IN PROGRESS
My most recent research focuses on the economic and environmental effects of urban development, especially tall building construction, and urban redevelopment in high- and middle-income countries including the United States.
1) Remi Jedwab and Gabriel Ahlfeldt. “The Global Economic and Environmental Effects of Vertical Urban Development”
Abstract: We use a global database of about 750,000 tall buildings of at least 55 meters (Emporis) and various identification strategies to study the city-level economic and environmental effects of tall building construction for a sample of 13,000 world cities, each with at least 50,000 inhabitants, from the 1970s to date. Preliminary evidence suggest that larger stocks of tall buildings promote economic development for cities (as measured by population and night lights) while reducing their environmental footprint (land area, sprawl, congestion, and pollution). The mechanisms are examined using firm-level surveys.
2) Remi Jedwab. “The Economic and Environmental Effects of Vertical Urban Development in the U.S.”
Abstract: While the previous analysis has the merit of being global, there are also data limitations in terms of the outcomes that can be studied. For example, historical panel data on city incomes and property prices do not exist except in a few countries, and there is also limited data at the world level on the mechanism by which tall buildings promote economic development and economic densification (per area). This project’s goal is to deepen our understanding of the effects of vertical urban development by focusing on a sample of 200-350 metropolitan areas in the U.S. from the late 19th century (1884 when the first skyscraper was built) to date. An analysis over this long period will also allow us to investigate the economic effects of the earlier skyscraper boom that the U.S. experienced before the Great Depression of 1929.
3) Remi Jedwab. “Quantifying Building-Height Gaps in the U.S.”
Abstract: In the paper “Cities Without Skylines: Worldwide Building-Height Gaps and their Possible Determinants and Implications” (see Working Papers above), we use geospatialized data on 25,000 tall buildings of at least 80 meters in the world (CTBUH database), including information on their year of construction, height, and function (e.g., residential vs. commercial) to measure how many “missing” tall buildings there are in the world due to building-height restrictions (we find strong gaps for the U.S. and some European countries). We show how such restrictions constrain vertical development in cities and increase housing unaffordability, sprawl, and pollution, using data on property prices and land and environmental footprint for a large sample of world cities. While we perform a similar gap analysis using decadal U.S. state-level data from 1929 to 2017, I plan to use the same methodology as well as better data on tall buildings (Emporis, which includes buildings from 55 meters instead of 80 meters like CTUBH) and the drivers of tall building construction to identify city-level gaps and examine their determinants.
4) Remi Jedwab. “Are we Over-Building in “Bad” Locations Globally? Evidence on the Non-Effects of Future Climate Change on Global Urban Construction Today”
Abstract: I use the same tall building data sets (Emporis and CTUBH) to study whether the world is over-building skyscrapers in “bad” locations. For example, Dubai is the city where the world has built the most in the past 20 years. According to the data, it is also the city where the world is planning to build the most in the next 10 years (the databases also include “proposed” projects). However, Dubai is also the city that will be the most impacted by future temperature increases, while skyscrapers are extremely durable (unlike houses and low-rises). We ask to what extent international policymakers should reduce restrictions on investments from Gulf countries, for example in the U.S., so that these very valuable investments can move to countries and locations relatively less impacted by future climate change. Our results should also have implications for important U.S. cities that will likely be impacted by climate change in the future, such as Phoenix, Los Angeles, New Orleans, or Miami. For example, Los Angeles will likely suffer from higher temperatures, threats to its water supply, increased fire rates, and rising sea levels.
5) Remi Jedwab and Jingwen Zheng. “Estimating the Negative Externalities from Urban Blight: Evidence from the Demolition of Kowloon Walled City in Hong Kong”
Abstract: It is difficult to causally estimate the negative externalities from urban blight. We exploit a natural experiment that led to the demolition in 1994 of the densest slum in the history of mankind, Kowloon Walled City (KWC), a vertical slum of 50,000 residents. While the existence of KWC likely had negative visual blight effects on neighboring blocks, KWC was also notorious for drugs and crime. Using census block data from 1981 to 2016, we investigate the effects of the demolition on employment and other economic outcomes in neighboring locations. We check for pre-trends and argue that the timing of the slum’s demolition was exogenous. We then distinguish the effects in the short-run and the long-run.
6) Remi Jedwab. “The Economic and Environmental Effects of Building-Height Restrictions: Causal Evidence from Sao Paulo”
Abstract: I study the effects of building-height restrictions that were exogenously imposed in Sao Paulo, which at one point had among the largest stocks of tall buildings in the world. More precisely, after 200 people died and hundreds were injured when two 100-meter-tall towers burned in 1972 and 1974, the city adopted more stringent height restrictions, which made the city’s form evolve towards one of a cylinder instead of a cone. I plan to use historical and contemporary data at the block level to predict which blocks have exogenously seen their tall building supply become less elastic and binding, and the local, spill-over and general equilibrium effects of such changes on population, employment and other economic outcomes.