It is becoming increasingly apparent that the goal of no more than a 2 degrees C. rise in global temperatures established by the Paris Agreement will not likely be met in a reasonable time frame.  Post-pandemic global emissions are expected to continue to rise as more fossil fuel plants, including coal, are still being planned or placed into service for the foreseeable future, while countries that are reducing emissions are missing their goals.  And while proposals for taking carbon dioxide out of the atmosphere are emerging, it will take decades for these to prove themselves and scale up to the levels required.  Meanwhile, deforestation, severe droughts, raging fires and more powerful hurricanes appear to be happening faster than expected.

With this as a backdrop, Dr. Keith argues that solar geoengineering may be a viable option in that it could be implemented fairly easily and at low cost, estimated at $5B per year, yet offset the impact of many decades of carbon emissions.  Research done to date by his team and international colleagues, suggests that the identified risks may prove manageable, but that much more research needs to be done to create a greater assurance that unintended consequences can be understood and controlled.

He will first review the science and technology of solar geoengineering, addressing its effectiveness in reducing climate risks. Then he will describe how solar geoengineering may create new non-climate risks and analyze their potential severity.  Finally, he will discuss how a substantial research program could further reduce risk and uncertainty.  He will then propose a case for integrating solar geoengineering into a climate policy that includes a full range of emissions cuts, major carbon removal approaches and adaptation.  In his proposal, solar geoengineering is positioned as a long-time frame but temporary bridge to buy time to get to net zero emissions and fully implement carbon removal without blowing away the 2 degrees C. goal altogether.