A Potent Greenhouse Gas Was Supposed to Be Eliminated. But Something Is Wrong https://www.sciencealert.com/a-super-greenhouse-gas-we-d-almost-eliminated-is-back-and-worse-than-ever?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencealert-latestnews+%28ScienceAlert-Latest%29