Dr. Matt Rigby of the MIT Center for Global Change Science will present in the MIT Atmospheric Science Seminar Series. Abstract: Measurements by the Advanced Global Atmospheric Gases Experiment (AGAGE) and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) show renewed growth of atmospheric methane from early 2007 to present. This rise follows almost a decade of relatively stable global levels and has occurred at all monitoring locations almost simultaneously. I will investigate the probable causes of this strange anomaly using 2D and 3D chemical transport models. Sulfur hexafluoride is an extremely potent greenhouse gas, with a lifetime of thousands of years. Its atmospheric burden has risen dramatically over the last few decades and continues to grow, despite efforts to control emissions. We use NOAA and AGAGE atmospheric measurements to try to determine which regions may be responsible.