The excitation of Earth's rotation by atmospheric pressure fluctuations, on timescales from days to years, is modified by the oceanic response to the pressure load. That response has often been approximated as a static, inverted barometer (IB) change in sea level; but evidence from theory and both tide gauge and altimetric data suggests that the IB poorly models the sea level response at short periods. Static models also fail to account for the currents induced by the pressure loading. The actual, dynamic response of the oceans to barometric loads depends on frequency and on the spatial structure of the loading. This work presents a Green's function approach to determining the rotational effects of that oceanic response. The Green's functions characterize the rotational effects of the oceanic response to pressure loads described spatially by individual spherical harmonics. For each harmonic of forcing they were computed at nine periods, ranging from 4 days to 18 years, and interpolated at intermediate periods. Computations were based on solutions to the author's dynamic spherical harmonic ocean tide model. The effects on rotation of the dynamic barometer oceanic response are obtained by a convolution-type combination of the Green's functions with actual atmospheric pressure data. Results for data spanning the past decade will be illustrated using harmonically decomposed National Center for Environmental Prediction (NCEP) and European Centre for Medium-Range Weather Forecasts (ECMWF) pressure fields. ¿ 1998 American Geophysical Union