In 1883, Krakatoa erupted, spewing volcanic ash and gas into the stratosphere, making clouds more reflective and cooling the entire planet by roughly 1° C that year. In 2018, the UN reported that human activity has already raised Earth’s temperature by 1°, and if we don’t do something drastic soon, the results will be catastrophic. The optimal solution is staring us in the face, of course; reduce carbon emissions.