A 10-year run of the Bureau of Meteorology Research Centre atmospheric General Circulation Model is analyzed in the tropical Pacific to determine its heat flux response to El Ni¿o/Southern Oscillation sea surface temperature anomalies. It is determined that the expected negative feedback occurs with approximately the right magnitude. Such a feedback occurs primarily as a result of changes in the latent heat flux. In addition to this local feedback in the eastern Pacific a response of the opposite sign occurs in the Indonesian region. Again this is caused mainly by evaporation changes. These changes are caused by changes in the scalar wind speed not associated with circulation changes implying that changes in the variance of the wind are important. Radiative changes were found to be, in general, less important and are associated with changes in low-level clouds.