Add enough iron, the argument goes, and the algae will grow and multiply, soak up excess carbon dioxide from the atmosphere, and so reduce the greenhouse effect. (newscientist.com)
They would have the effect of reflecting some of the incidental sunlight into space thereby reducing the greenhouse effect. (newstatesman.com)
But then sometimes I think: NOTHING that I do for the remaining decades of my life is going to have even the most infinitesimal impact on reducing the greenhouse effect in my lifetime. (dotearth.blogs.nytimes.com)