The blue line is RSS, the black line is UAH, the red line is the CMIP5 mean and the grey bands show the RCP4.5 range.
The thin white lines denote the central 66% and 95% ranges. Even with the 2016 El Nino the discrepancy is visible and the observations do not cross the CMIP5 mean after 1999.
found that the discrepancy between models and observations declines somewhat. shows that the use of SAT/SST (“blended”) model output data doesn’t actually close the gap by much: the majority of the reconciliation happens by using “updated forcings”, i.e. With the 2016 El Nino at the end of the record a crossing between the observations and the modified CMIP5 mean occurs.
On a 1970-2000 centering the max value of the CMIP5 ensemble exceeds 1C in 2012, but in Hausfather’s graph that doesn’t happen until 2018.
The ranges of observed trends reflect observational uncertainty, whereas the ranges of model trends reflect forcing uncertainty, as well as differences in individual model responses to external forcings and uncertainty arising from internal climate variability.
The IPCC’s Fifth Assessment Report also acknowledged model over-estimation of recent warming in their Figure 9.8 and accompanying discussion in Box 9.2. I set the CMIP5 range to gray, and the thin white lines show the (year-by-year) central 66% and 95% of model projections.
This would appear to confirm the claim in Millar et al.
that climate models display an exaggerated recent warming rate not observed in the data.
Apples with Apples The basic logic of the Cowtan et al. The question is whether their approach, as shown in the Hausfather graph, actually reconciles models and observations.