Scientists are examining the possibility of using solar radiation management (SRM) techniques to protect the Earth from the amount of sunlight hitting our planet.  Materials would be transported to the stratosphere to provide shading of the Earth.  This high tech solution is being considered both feasible and cost effective. But, it does nothing to reduce greenhouse gases or ocean acidification, nor is the reduction in radiation uniform across the world.  Read more here.

Image from nationalgeographic.com