This morning, Bloomberg Philanthropies announced a $50 million grant to the Sierra Club, to be doled out over four years. The Sierra Club says they'll use the money for their "Beyond Coal" campaign, which works to transition the nation away from coal.The Sierra Club said the gift from Bloomberg will effectively retire one-third of America's aging coal-fired power plants by 2020, and replace them with clean energy. The announcement was made in front of a power plant in Alexandria, Virginia, by New York City Mayor Michael Bloomberg and Sierra Club Executive Director Michael Brune.In a statement released by the Sierra Club, Bloomberg said:"If we are going to get serious about reducing our carbon footprint in the United States, we have to get serious about coal. Ending coal power production is the right thing to do, because, while it may seem to be an inexpensive energy source, the impact on our environment and the impact on public health is significant," Bloomberg said. "Coal is a self-inflicted public health risk, polluting the air we breathe, adding mercury to our water, and the leading cause of climate disruption."