the latest observations reported by the IPCC proves that the climate seems to be less sensitive to changes in the greenhouse gas increases than the previous IPCC report indicated.
OK. This is well and good; now the IPCC’s new estimates are reflecting the latest science.
Unfortunately, the IPCC’s climate models are not.
If we examine the climate models chosen by the IPCC to make their projections of future climate change resulting from human greenhouse gas (and particulate) emissions, we find that instead of using models with a 20 percent lower transient climate sensitivity, the transient sensitivity of the models used by the IPCC isthe same in the AR5 as in the AR4.
This has two serious implications.
First is that the climate models using by the IPCC are running behind the latest science, and secondly, and quite significantly, the climate models used by the IPCC produce too much warming for a given rise in atmospheric carbon dioxide levels. This means the climate model projections, which make up the meat of the IPCC Assessment Report (and upon which policy decisions the world around are based), are substantially overheating.
The IPCC implicitly admits this fact through its own numbers.
Now, if only they would admit this explicitly. Then we’d be getting somewhere. But, while they may pay small lip service noting things might not be all right, don’t hold your breath waiting for the IPCC to say “we goofed.”
