From brightening ocean clouds to launching sulfur dioxide into the stratosphere, some entrepreneurs and scientists are testing technology that could reflect sunlight back into space to combat global warming. There's evidence some types of solar geoengineering could lower global temperatures a lot. But along with potential benefits come huge potential risks. Experts say the science isn't settled and regulations aren't keeping up. Today on The Sunday Story, a journey into the world of solar geoengineering. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy