Stephen O. Andersen protecting the stratospheric ozone layer. At EPA he rose to Deputy Director for Stratospheric Ozone Protection and then transferred to the Climate Protection Partnerships Division, where he was Director of Strategic Climate Projects until his retirement from government in 2009. The timing of Andersen’s arrival at EPA was fortuitous. 1987 proved to be a watershed moment in the effort to stop ozone depletion, which increased risks of skin cancer and threatened to wipe out crops and ecosystems, among many adverse impacts. The Montreal Protocol on Substances that Deplete the Ozone Layer was agreed on 16 September 1987 and created a
Montreal Protocol and HCFCs. Thus, in 2009, a study calculated that a fast phasedown of high-GWP HFCs could potentially prevent the equivalent of up to 8.8 Gt CO2-eq "per year" in emissions by 2050. A proposed phasedown of HFCs was hence projected to avoid up to 0.5C of warming by 2100 under the high-HFC growth scenario, and up to 0.35C under the low-HFC growth scenario. Recognizing the opportunity presented for fast and effective phasing down of HFCs through the Montreal Protocol, starting in 2009 the Federated States of Micronesia proposed an amendment to phase down high-GWP HFCs, with the U.S., Canada, and