Current Research

Novel Analyses of Existing Solar Geoengineering Simulations

I am re-evaluating results from the well-studied Geoengineering Model Intercomparison Project (GeoMIP). The goal of this work is to more clearly show the possible benefits and risks of solar geoengineering by showing the effects of solar geoengineering in the context of the expected response to elevated Greenhouse Gas (GHG) concentrations. The novel analyses I am preparing will clearly distinguish between the case where solar geoengineering adds to the effects of GHG warming and where it offsets too much of this effect, changing the sign of the response.

Analysis of high-resolution simulations of solar geoengineering

I am working to evaluate the climate response to solar geoengineering in the very high-resolution GFDL HiFLOR global climate model. This work will be the first using a model of this class, which can directly simulate tropical cyclones up to category 5 and has a much more realistic representation of regional precipitation patterns and of extreme precipitation events. The analysis will focus on the extreme temperature and precipitation response and will compare these responses to those seen in the GeoMIP ensemble.

The ice-sheet surface mass balance response to solar geoengineering

Solar geoengineering is virtually certain to reduce ice sheet mass loss as it will lower surface air temperatures which drive mass loss from the surface of ice-sheets, however there are uncertainties about it's overall efficacy. This project has two goals: to make a theoretical evaluation of the potential response of ice sheet surface mass balance to solar geoengineering, and to make an initial assessment to confirm these theoretical judgements using the GeoMIP ensemble.

The risk of termination shock

If solar geoengineering were deployed at large-scale and were suddenly, permanently terminated, a rapid warming would follow which would likely have substantial impacts. The effects and implications of such a "termination shock" have been widely discussed in the geoengineering literature but few have stopped to ask: how likely is this? and what can be done to reduce this risk? Andy Parker and I have found that the properties of stratospheric aerosol geoengineering mean that simple precautions could make for a very robust and resilient deployment system. We also argue that if one nation deploying solar geoengineering decided to terminate deployment others could easily step in to prevent a termination shock from occurring as the costs of deploying stratospheric aerosol geoengineering are low.