Mario Molina is best known for his study of the effect of man-made compounds on the ozone layer. In one of the most highly cited papers ever published (in Nature, 1974), Molina and his colleague, F. Sherwood Rowland, hypothesized that chlorofluorocarbons could have an adverse effect on the ozone layer. Subsequently, the “ozone hole” was observed over Antarctica in the early 1980s, validating their hypothesis. In recognition of their pioneering work, Molina and Rowland, along with Dutch atmospheric chemist Paul Crutzen, shared the 1995 Nobel Prize for Chemistry for their insightful work on the chemistry of ozone. In addition, Dr. Molina has received other prestigious awards form the American Chemical Society, the American Association for the Advancement of Science, and the United Nations Environmental Programme. In 2005, he established the Mario Molina Center for Strategic Studies in Energy and the Environment in Mexico City to tackle complex environmental issues. As climate policy advisor to Mexican president Enrique Peña Nieto, Molina was instrumental in pushing through an “ambitious” climate change law in 2012. In 2013, Molina received the Presidential Medal of Freedom from President Barack Obama.