The Carbon Bubble: Climate Policy in a Fire-sale Model of Deleveraging

Committed and credible implementation of climate change policy, consistent with the usual 2C limit, is thought to require large fossil fuel asset write-offs. This issue, termed the Carbon Bubble, is usually presented as having implications for investors but, for the first time, this paper discusses its implications for macroeconomic policy and for climate policy itself. We embed the Carbon Bubble in a macroeconomic model exhibiting a financial accelerator: if investors are leveraged, the Carbon Bubble may precipitate a fire-sale as investors rush for the exits, and generate a large and persistent fall in output and investment. We investigate policy responses which can accompany the writing-off of fossil fuel assets, like debt transfers, investment subsidies, government guarantees, or even deception about the true scale of the required write-off of fossil fuel assets. We find a role for policy in mitigating the Carbon Bubble.