I’m not understanding your math here, hopefully you (or anyone with a better grasp of logarithms than me), can walk me through it.
I know a doubling is not the same as four +25% added together. The last 75% isn’t as effective as the first 25%.
200ppm — 400ppm = +100% = 1C
200ppm — 250ppm = +25%
250ppm — 312ppm = +25%
312ppm — 390ppm = +25%
390ppm — 488ppm = +25%
Am I missing part of your intended argument? Did I get your math wrong?
I think I can sort of see maybe 3 * 0.64 = 1.92, and you get close to the doubling at 390, call the last .07 the last 10ppm, but this sort of opens up the can of worms with 18+ years of increasing CO2 and no statistically significant temperature increase, don’t you think?