Climate change is generating demonstrable harm around the world. Political and legal efforts have sought to associate climate impacts with specific emissions, including in recent international policy discussion of Loss and Damage (L&D). However, no quantitative definition of L&D exists, nor does...

Reductions in greenhouse gas emissions are a global public good, which makes it efficient to act globally when addressing this challenge. We lay out several reasons that high-income countries seeking to mitigate climate change might have greater impact if they invest their resources in...

Many US states have set ambitious renewable portfolio standards (RPS) that require utilities to switch from fossil fuels toward renewables. RPS increases the renewables capacity, bond issuance, maturity, and yield spreads of investor-owned utilities compared to municipal producers that are...

Flood events and flood risk have been increasing in the past few decades and have important consequences for the economy. Using county-level and ZIP-code-level data from the United States during 1998-2018, we document that (1) increased flood risk has a large negative impact on firm entry,...

Shared socioeconomic pathways (SSPs) are perhaps the most influential economic policy analyses today. My paper evaluates their development, natural associations, logical consequences, and economic identification. All five SSP baseline scenarios are predicting scenarios that historical...

This paper estimates that the macroeconomic damages from climate change are six times larger than previously thought. We exploit natural variability in global temperature and rely on time-series variation. A 1°C increase in global temperature leads to a 12% decline in world GDP. Global...

Do governments systematically intervene in agricultural markets in response to climate shocks? If so, what are the aggregate and distributional consequences? We construct a global dataset of agricultural policies and extreme heat exposure by country and crop since 1980. We find that extreme heat...

Innovation depends on exporting and, in particular, on scale and competition in export markets. We develop a theory featuring (1) quality-segmented markets, (2) step-by-step innovation that moves firms forward along the quality ladder, and (3) escape-the-competition motives for innovation. We...

After decades of rising global economic integration, the world economy is now fragmenting. To measure this phenomenon, we introduce an index of geopolitical fragmentation derived from various empirical indicators. This index is developed using a flexible dynamic factor model with time-varying...

We provide semiparametric identification results for a broad class of learning models in which continuous outcomes depend on three types of unobservables: i) known heterogeneity, ii) initially unknown heterogeneity that may be revealed over time, and iii) transitory uncertainty. We consider a...