Twelve years of satellite data on water vapor tell us that, of the 15 climate models we've been using only, 5 predicted humidity correctly. Since water vapor doubles the warming caused by CO2, it's an amplifier. The only models that got humidity right were the ones which predicted the hottest future.
In a recent study, Su and her research team used AIRS observations of humidity to analyze the performance of 15 leading global climate models. What they found was surprising: Only five of the models reproduced humidity levels that matched the current range observed by AIRS and other instruments. Even more startling, those models that did accurately forecast current humidity were the ones that predicted a much warmer future climate—about .7 degrees C (1.3 degrees F) higher than the average warming predicted by all 15 models combined.
“It’s kind of an ‘inconvenient truth’—the models that are realistic all happen to be the ones that are predicting a very strong warming in the future,” said Su.
According to Fetzer, Su’s findings beg two important questions: “First, why are we looking at models that don’t accurately produce what we’re experiencing today? And second, if the models that are accurately forecasting humidity say that future warming is going to be closer to 4 degrees C than 1.5 degrees C, shouldn’t we be concerned?” [emphasis mine]
In case you forgot, at 4° C warming the carrying capacity of Earth is expected to drop to about half a billion, and other accelerating feedbacks are guaranteed to kick in.
...4 degrees C would very likely be a way station on the road to much higher temperatures.
I'm glad I've got no children, but I keep worrying about other people's children.