SHADED PLANET Solar geoengineering proposals could combat global warming by injecting reflective particles (blue) into the atmosphere above clouds (gray). By reflecting and scattering light, the particles could cool Earth’s temperature and alter rainfall patterns. But that also could reduce the growth of crops (green).
J. Proctor and S. Hsiang
Shading Earth by adding a veil of particles to the upper atmosphere may help to offset global warming — but at a cost.