At a press conference on July 21, New York City Mayor Michael Bloomberg announced that he was contributing $50 million to the Sierra Club's Beyond Coal Campaign. Michael Brune, head of the Sierra Club, called it a "game changer". It is that, but it also could push the United States, and indeed the world, to a tipping point on the climate issue.
It is one thing for Michael Brune to say coal has to go, but quite another when Michael Bloomberg says so. Few outside the environmental community know who Michael Brune is, but every business person knows Michael Bloomberg as one of the most successful business entrepreneurs of his generation.