Some scientists are working on enormous, mirrored parasols to be launched into the stratosphere, which would reflect sunlight back into space and theoretically cool Earth’s atmosphere over time. The Keutsch Research Group at Harvard University is hoping to launch the first ever major aerosol injection trial, known as the Stratospheric Controlled Perturbation Experiment (SCoPEx). The scientists will use a balloon to inject huge amounts of aerosols, or extremely fine particles, into the upper atmosphere, reflecting sunlight. They plan to use a high-altitude balloon to lift an instrument package approximately 20 kilometers into the atmosphere. Once it is in place, a very small amount of material (100 grams to 2 kilograms) will be released to create a perturbed air mass roughly 1 kilometer long and 100 meters in diameter. They will then use the same balloon to measure resulting changes in the perturbed air mass including changes in aerosol density, atmospheric chemistry, and light scattering. Bill Gates and other private donors put $16 million behind the Harvard projects, but some scientists warn the experiments are risky because they threaten to adversely disrupt natural weather patterns, potentially causing extreme flooding and drought in various parts of the world—mostly in poorer countries.