Hansen notes that solar brightness has decreased and the effects are “not negligible.”
[You can’t expect global temperature to increase at a constant rate because] there’s too much natural variability. There are otehr forcing factors. It’s not only CO2 that’s changed. The sun’s brightness changed, ah decreased slightly over the last 10 years, about 0.1 watt/m2. That’s not as large as the climate forcing that you get from CO2, but it’s not negligible.