Table 1. Correlation and information flow between observed global surface temperature and different external forcing’s and internal climate variations.

Radiative Forcing	Correlation and Causality–HADCRUT4
	Correlation	Forcing→GMTA[nat/year]	GMTA→Forcing[nat/year]
Total forcing	0.804 ± 0	0.244 ± 0.091	0.036 ± 0.080
Anthropogenic	0.863 ± 0	0.355 ± 0.112	−0.008 ± 0.005
All GHG	0.852 ± 0	0.318 ± 0.108	−0.005 ± 0.003
CO2	0.852 ± 0	0.316 ± 0.108	−0.003 ± 0.003
Aerosol	−0.810 ± 0	0.232 ± 0.095	−0.002 ± 0.006
Cloud	−0.796 ± 0	0.208 ± 0.092	−0.001 ± 0.004
Solar	0.616 ± 0	0.082 ± 0.059	0.035 ± 0.051
Volcanic	0.089 ± 0.267	0.003 ± 0.006	−0.004 ± 0.009
AMO (1900–2008)	0.477 ± 0	0.018 ± 0.043	0.021 ± 0.014
PDO (1900–2008)	0.123 ± 0.204	−0.002 ± 0.013	−0.011 ± 0.025

The chosen unit time step is ut = 1 year.