I may have found your references for it, then when and looked at the IPCC AR4 and AR5 synthesis reports.
Between AR4 and AR5 page 9
AR4 SYR Synthesis Report - Figure 5.1
http://ipcc.ch/pdf/assessment-report..._FINAL_SPM.pdf
went from approx 2.5C to approx 1.75C for a doubling to 500ppm.