I study how policymakers can access and act on the information about climate change damages that is dispersed throughout the economy. I analyze a new dynamic deposit-refund instrument (called "carbon shares") that I show can: i) efficiently price emissions conditional on information, ii)...

We investigate the optimal policy response to the possibility of abrupt, irreversible shifts in system dynamics. The welfare cost of a tipping point emerges from the policymaker's response to altered system dynamics. Our policymaker also learns about a threshold's location by observing the...