It is intended for those new to the presentation of global surface temperature anomaly data. (wattsupwiththat.com)
We can compare this with a similar reconstruction looking at surface temperature anomalies for the 1999 to 2008 period. (skepticalscience.com)
Given that we're mainly looking at the global mean surface temperature anomaly, the most appropriate comparison is for the net forcings for each scenario. (realclimate.org)