In Spring 2020, COVID-19 led to an unprecedented halt in public and economic life across the globe. In an otherwise tragic time, this provides a unique natural experiment to investigate the environmental impact of such a (temporary) "de-globalization". Here, we estimate the medium-run impact of a battery of COVID-19 related lockdown measures on air quality across 162 countries, going beyond the existing short-run estimates from a limited number of countries (

Globalization is routinely blamed for various ills, including fueling conflict in strategic locations. To investigate whether these accusations are well founded, we have built a database to assess any given location’s strategic importance. Consistent with our game-theoretic model of strategic interaction, we find that overall fighting is more frequent in strategic locations close to maritime choke points (e.g., straits or capes), but that booming world trade openness considerably reduces the risks of conflict erupting in such strategic locations. The impact is quantitatively sizable, as moving one SD (1,100 km) closer to a choke point increases the conflict likelihood by 25% of the baseline risk in periods of low globalization, while reducing it during world trade booms. Our results have important policy implications for supranational coordination.

In Spring 2020, COVID-19 led to an unprecedented halt in public and economic life across the globe. In an otherwise tragic time, this provides a unique natural experiment to investigate the environmental impact of such a (temporary) ‘de-globalization’. Here, we estimate the medium-run impact of a battery of COVID-19 related lockdown measures on air quality across 162 countries, going beyond the existing short-run estimates from a limited number of countries. In doing so, we leverage a new dataset categorizing lockdown measures and tracking their implementation and release, extending to 31 August 2020. We find that domestic and international lockdown measures overall led to a decline in PM2.5 pollution by 45% and 35%, respectively. This substantial impact persists in the medium-run, even as lockdowns are lifted, there is, however, substantial heterogeneity across different types of lockdown measures, different countries, and different sources of pollution. We show that some country trajectories are much more appealing (with fewer COVID-19 casualties, less economic downturn and bigger pollution reductions) than others. Our results have important policy implications and highlight the potential to ‘build back better’ a sustainable economy where pollution can be curbed in a less economically costly way than during the COVID-19 pandemic.

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Containing a pandemic is first and foremost a management problem: one has to find ways to reduce mobility and physical contacts in order to slow down the spread of the virus. We discuss and construct a novel database of internal and external lockdown measures around the world and analyze whether they helped reduce the spread of infections and the number of deaths. We address the endogeneity of lockdowns by modeling anticipation effects. Our data cover 178 countries in the period from December 2019 to November 2020 and identify lockdown and release periods along with confirmed cases of infections and deaths resulting from COVID-19. Overall, we find that lockdowns were effective, reduced mobility, and saved about 3.6 million lives in developed countries within 100 days after they were implemented. Measures taken within countries (rather than border closure) and partial lockdowns (instead of more constraining measures) were the most effective. However, in developing countries, where the opportunity cost of staying home might be too high for people to comply, lockdowns were ineffective. Additionally, the release of lockdown measures, which started in mid-May 2020 in most countries, did not lead to a strong resurgence of the virus except for border closure releases. This paper was accepted by Stefan Scholtes, healthcare management. Supplemental Material: The data is available at https://doi.org/10.1287/mnsc.2022.4652 .