The economic case for limiting warming to 1.5°C is unclear, due to manifold uncertainties. However, it cannot be ruled out that the 1.5°C target passes a cost-benefit test. Costs are almost certainly high: the median global carbon price in 1.5°C scenarios implemented by various energy models is more than US$100 per metric ton of CO2 in 2020, for example. Benefits estimates range from much lower than this to much higher. Some of these uncertainties may reduce in the future, raising the question of how to hedge in the near term.
Prof Simon Dietz is an environmental economist with particular interests in climate change and sustainable development. He is based at the London School of Economics and Political Science (LSE), where he is Professor of Environmental Policy in the Grantham Research Institute on Climate Change and the Environment, and the Department of Geography and Environment.