There’s a strong case to be made that coal is humankind’s thorniest problem. It’s the chief source of the world’s energy—it currently keeps the lights on in 40 percent of the world—and simultaneously the globe’s biggest contributor to climate change. It provides cheap power, but infects and kills hundreds of thousands with respiratory illnesses. It’s a nightmare scenario—we’re reliant on what’s killing us. And it’s only been getting worse.
See http://motherboard.vice.com/blog/coal-burning-is-up-50-worldwide-and-its-killing-more-people-than-ever.