I suggested that here ages ago. Some sort of solar shielding would help, but the size of these things would have to be enormous. Its a last resort.
And as the CO2 continued to rise underneath, more and more shading would be required.
The guy is right tho, we have the technology to combat this already, its called renewable energy systems.
With renewables you can use as much energy as you need, and the atmosphere stays clean.
Finally, we know the oil is going to run out if we keep using it - 20-40 years max, so renewables will be needed eventually. Nuclear is simply a messy, nasty for all eternity, process that we don't want. Wind turbines are the answer - offshore, and the bigger the better. Germany has 5 prototypes of the new e-112 4.5 MW turbines complete - each one provides enough energy for 4,200 households.
Dave L