61regression constant C 0 (not shown). Finally, the bottom panel shows a comparison of a
time series of OHC (available only from 1950 to 2007) to the modeled QOCEAN term.
Figure 2.5 is similar to Fig. 2.4, except here the model has been expanded to include
the AMV, PDO, and IOD terms in Eq. 2.2. The OHC comparison is not shown in Fig.
2.5 because it looks identical to the bottom panel of Fig. 2.4. The red curve on the top
panel of Fig. 2.5 is the sum of the curves shown in the rest of the panels, plus the con-
stant C 0. The top panel of Fig. 2.5 shows remarkably good agreement between observed
ΔT from CRU (black) and modeled ΔT found using the EM-GC equation (red).
Fig. 2.5 Observed and EM-GC simulated global warming, 1860–2015. Same as Fig. 2.4, except
the EM-GC equations have been expanded to include the effects of the Atlantic Meridional
Overturning Circulation (AMOC), the Pacific Decadal Oscillation (PDO), and the Indian Ocean
Dipole (IOD). The fifth rung of the ladder plot shows contributions to variations in ΔT from fluc-
tuations in the strength of the AMOC; the sixth rung shows contributions from PDO and IOD. See
Methods for further information
2.2 Empirical Model of Global Climate