Perhaps the award selection committee considered the fact that "this issue has been in the forefront of discussion for over 30 years" and very little has been done beyond studies and more studies:
"for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change"
Will the award help stimulate action....or will we just have more studies for the next 30 years? Who knows.