Is solar geoengineering research having its moment?

How would the world react if one country launched a solar geoengineering project to cool the planet without the permission of others? Would the sky change colour based on the type of particles injected into the upper atmosphere? Even if global average temperatures cooled in response, how would rainfall change over Africa? These are just some of the questions about solar geoengineering scientists grappled with at a December meeting of the American Geophysical Union (AGU) in Washington DC, and they…