The black "observed" line is the GISS global land and ocean temperature record, which can be found here. It starts in 1880.
The colored temperature lines are the modeled estimates that each climate factor contributes to the overall temperature. Each factor was simulated five times, with different initial conditions; each trace here shows the average of five runs. GISS researchers laid out their historical simulations in detail last year in this article.
All the lines on the plot show the variance from the 1880-1910 average of the parameter.
The graph and writeup is from the Bloomberg Climate Change graph.