As I said before, reducing input of sunlight is one way to fight the change. Not that we really want the nuking and all. Also hard to balance this right, too much and it gets colder.
Another option is to build a solar shield / mirror the circumference of the earth at the Lagrange point between earth and sun. Huge LCD shutter glasses to control how much light can get through :) Of course with current tech no chance.
I wonder if solar panels provide cooling. They keep your roof 3c cooler, yet that's just preventing the heat from reaching your roof. Do they actually convert solar heat to energy? I'm guessing using mirrors to focus sunlight at a central point to turn water into steam does take heat away. You probably need to cover the entire desert with these to make any kind of difference.