They are different scenarios for the amount of carbon dioxide is eventually put in the atmosphere. Contrary to what Kano says, they are not (totally failed) climate models. Each of these scenarios is a possible future that hasn't happened yet. And the Y-axis of the graph in my link is energy imbalance, not temperature.

http://www.pik-potsdam.de/~mmalte/rcps/

Oh I'm sorry, it appears I have accidentally stumbled on to the nerd side of yahoo answers. I'm just trying to find my way back.

They are different scenarios of (totally failed) climate models, who's results bare no resemblence to reality.

We need to know what CMIP5 means first.