co2 emissions from power plants represent a breakthrough not only in the u.s. government ambition to halt climate change, but also a breakthrough in methods to did s s ts to do so. they will be attacked. i will say up front much more needs to be done, yet it is a day for celebrating. >> despite everything, we're finally taking some action to do something about this growing danger. and i think the epa rules which tell the states get with it, make plans, get serious, what are you going to do about your pourer pla power plants, is an important step forward. and i think there will be 1,000 legal challenges, but this is going forward and this is part of a global effort now which i think we're going it hear a lot more about because there is a global agreement to reach an agreement a year from december. and china is working on this.