| 8:30 AM | 13.2 | Interannual changes in the global direct radiative climate forcing by well-mixed greenhouse gases over the past 25 years  David J. Hofmann, NOAA/Climate Monitoring & Diagnostics Lab, Boulder, CO; and J. H. Butler, E. J. Dlugokencky, J. W. Elkins, K. Masarie, S. A. Montzka, and P. Tans |