75Fig. 2.10 (a) Observed and EM-GC simulated global warming, 1860–2015 as well as global
warming projected to 2060. Top rung of a typical ladder plot, comparing EM-GC modeled (red)
and CRU observed (black) ΔT, as well as three of the terms that drive ΔTHUMAN (Eq. 2.4) computed
for the AerRF 2011 = −0.9 W m−^2 , the IPCC ( 2013 ) best estimate for ΔRF due to aerosols, and com-
parison of modeled and measured OHC, for a simulation that derives a value for κ that provides
best fit to the OHC dataset of Ishii and Kimoto ( 2009 ). (b) Same as (a), expect for a simulation that
derives a value for κ that provides best fit to the OHC dataset of Levitus et al. ( 2012 ). (c) Same as
(a), expect for a simulation that derives a value for κ that provides best fit to the OHC dataset of
Gouretski and Reseghetti ( 2010 ). Note how the values of Equilibrium Climate Sensitivity given in
(a)–(c) respond to changes in OHC, whereas the transient climate response (red curve, upper rung
of each ladder plot) are nearly identical. Also, smaller values of Attributable Anthropogenic
Warming Rate (AAWR) are found as OHC rises, due to interplay of the OHE and aerosol terms
within ΔTHUMAN
a
b
2.2 Empirical Model of Global Climate