Climate tipping points and solar geoengineering

We study optimal climate policy in the presence of climate tipping points and solar geoengineering. Solar geoengineering reduces temperatures without reducing greenhouse gas emissions. Climate tipping points are irreversible and uncertain events that can alter the dynamics of the climate system. We analyze three different rules related to the availability of solar geoengineering, and we model three distinct types of tipping points. Before reaching the tipping point, the introduction of solar geoengineering reduces the amount of mitigation, lowers temperatures and increases carbon concentrations. The capacity of solar geoengineering to deal with climate damages depends on the type of tipping point. Solar geoengineering is most effective at dealing with tipping points that affect the responsiveness of temperature to carbon, and it is least effective at dealing with tipping points that cause direct economic losses.