FIGURE 2. Northern Hemisphere mean radiative forcing.

Sub-annual forcing data are used in the climate model simulations, but a decadal filter is applied here for illustration only, to focus on timescales most relevant for the analysis. For tropospheric aerosol forcing (green), a range of forcing has been used; for solar (pink) and volcanic (blue) forcing, a best guess forcing (dark, thick line) and a gaussian uncertainty range has been used (2.5% and 97.5% limits are shown by light, thin lines, the lower limit for solar is on the zero line). For clarity, greenhouse gas ('GHG') and aerosol forcings are offset by 3 W m^-2, and solar forcing by 1 W m^-2.