Most people consider parks important for their quality of life, yet systematic causal evidence is missing. We exploit exogenous variations in their use values to estimate causal effects. Using a representative household panel with precise geographical coordinates of households linked to...

This paper considers the question under what conditions domestic markets of emission permits would and should merge to become an international market. Emission permits are licenses, and so governments would need to recognize other countries' permits. In a two-county model, we find that it is in...