[palmer]

Now, the concept that the 0.2% increase in the solar irradiance having CAUSED the 0.2% of temperature increase on the earth over the last 150 years is gaining more and more recognition.

Assuming no albido and no GH effect, the radiation emitted from the earth of the incident radiation in your chart (1366 now, 1364.5 in 1900). The stefan-boltzman constant is 5.67x10^-8 so:
4th root of ((1364.5 / 4) / (5.67 x (10^(-8)))) = 278.50476
4th root of ((1366 / 4) / (5.67 x (10^(-8)))) = 278.581269
or a 0.03 percent temperature increase from the increased irradiance and the rest from other sources.

[AFPhys]

Yeah... ignore Water Vapor, and albedo, and its pretty cold that way, ain't it?

Obviously, something else must be going on that is not accounted for by Stefan-Boltzman, huh? If not, it would be might cold on this ol' rock.

Let me propose one of the mechanisms that might, just possibly, just maybe, might respond slightly more linearly than than SB: Water Vapor and one of the effects of that, clouds.

That the % increase in temperature so closely matches the % increase in the irradiance of the Sun for over a thousand years might just serve as a clue for us, if we weren't so "intelligent".