Poster #138 - Climate Maladaption and the Commons: Groundwater Management in India

• In Event: Friday Poster Reception

Abstract

India is the world’s largest groundwater user, with 90% used for agriculture. However, groundwater depletion represents a classic tragedy of the commons, threatening agricultural sustainability. We develop a tractable model to show how a popular policy intervention — subsidizing efficient irrigation technology — can exacerbate distortions away from socially optimal groundwater extraction when extraction externalities are severe. To test the model’s key predictions, we leverage physical variation in the extent of extraction externalities and a multi-state groundwater management scheme that subsidized irrigation efficiency upgrades.  We find that the impact of the policy depends on the severity of extraction externalities: extraction falls by 9.2% in low-externality areas but rises by 11.0% in high-externality areas. Low-externality farmers maintain cropping intensity with less groundwater input, while high-externality farmers crop same land more intensively. Finally, we find divergent effects on climate resilience: low-externality farmers extract less when rainfall is normal and extract more during droughts, while high-externality farmers do the opposite. Our findings illustrate that the same common pool conditions that justify an intervention also determine its impact. 

Authors

• Nikhil Basavappa, Columbia University
  Presenting Author

• Ricardo Pommer Muñoz, Columbia University
  Non-Presenting Co-Author