Humanity's Contribution To "Global Warming"

jellisky writes: "In a recent climate modeling experiment, researchers have attempted to calculate the effect humanity has had on our climate. The results and article suggest that humanity is mainly to blame for a few recent warming periods, but also suggests that there are many other effects that might be just as important at times, including an oceanic oscillation and a mysterious "residual effect". Anyone else curious about this "residual effect"? How much trust should we put into these models when people cannot classify what's happening in them? Most importantly, though, what have we learned?"