One-sided significance levels for correlations with the different forcing agents are shown, under the assumption that only positive relationships with GHG and CO2, and negative relationships with DVI, are physically meaningful. The gray bars indicates two different 200 year windows of data in the moving correlation, with the long-dashed vertical lines indicating the center of the corresponding windows. Below, we investigate possible such lagged relationships to forcing. A complimentary approach to the attribution of forcings involves the use of climate model forced with estimated histories of greenhouse, volcanic, and solar radiative forcings, to estimate the expected large-scale temperature trends in past centuries. Relationship between NH series and forcings as above, but employing varying value of lag of temperatures relative to forcing.
Symbols are same as above.
The first 5 panels make use of the 200 year window used above. In the first panel, we repeat the zero-lag case shown above for comparison, while the 2nd panel shows the results for 1 year lag, the 3rd panel 10 year lag, and the 4th panel 15 year lag. The 5th panel shows the results based on employing 100 year moving window in the time-dependent attribution analysis, and with a 15 year lag in the relationship of temperature to forcings. For lags much larger than 1 year, the relationship of temperatures to volcanic forcing is not physically meaningful, and is quite small. Thus, the relationship to volcanic forcing is not shown in the 3rd, 4th, and 5th panels.