Radiative forcing due to stratospheric ozone changes 1979-1997, using updated trend estimates

Recent estimates of stratospheric ozone changes since 1979, both from satellites and ground-based instruments, show a smaller rate of ozone loss than previous measurements indicated. This paper calculates the radiative forcing resulting from these ozone changes. The trends are derived from a combination of Stratospheric Aerosol and Gas Experiment (SAGE), Total Ozone Mapping Spectrometer (TOMS), and ground-based data. By combining these data in a variety of ways, several problems of determining an accurate forcing from available data are highlighted. Using only statistically significant changes, a "best guess" radiative forcing of -0.10+/-0.02 W m(-2) is estimated for the 1979-1997 period which is about 50% less negative than previous estimates of this forcing, but provides an offset of about 10% to the well-mixed greenhouse gas forcing over the same period.