[sixbrx]

It's not the saturation at the peak absorbtion frequencies that is driving the warming, it's the widening of the curves which raises absorbtion levels in nearby frequencies. The "saturated" argument was one of the first objections when the science was poorly understood. Krauss's book Physics of Climate CHange has a good account of this history. Check IPCC summaries to see how many models from the literature predict flattening at 0.7C additional warming if we don't curb emissions (spoiler alert: slim to none with many positing 5C or more additional warming in the 2100's if emissions aren't curbed).