` :::::This text, also from chapter 9, explicitly discusses as a ``delay``, the lag in warming response due to aerosols: ::::::``In contrast, changes in solar forcing can potentially explain only a small fraction of the observationally based estimates of the increase in ocean heat content (Crowley et al., 2003), and the cooling infl uence of natural (volcanic) and anthropogenic aerosols would have slowed ocean warming over the last half century. Delworth et al. (2005) fi nd a delay of several decades and a reduction in the magnitude of the warming of approximately two-thirds in simulations with the GFDL-CM2 model that included these forcings compared to the response to increasing greenhouse gases alone, consistent with results based on an upwelling diffusion EBM (Crowley et al., 2003).`` :::::  `