The Kyoto Protocol is/was an environmental treaty which was originally developed on 11 December 1997 in Kyoto, Japan and effective 16 February 2005. The U.S. signed, but the the Senate refused to ratify the treaty.
On surface, it sounded good - the countries would all reduce greenhouse gases by over 5 percent. The problem though, is the world's largest emitter, China received a free ride. So did Brazil and India. Parts of the protocol begin expiring at the end of the year.
Climate Talks Near Close, No Breakthroughs Expected tells that the United States has developed a different strategy for the conference in Durbin, South Africa. The U.S. position is basically, 'we are not signing up to anything unless China does'. China is refusing, reiterating their position that they are an impoverished nation and all the greenhouse gas currently in the atmosphere belongs to the rich western world.
UN Climate Talks to Seek New Deal explains there is a divide - those that produce larger quantities of greenhouse gases and those that don't. But the problem is that if the largest producer of greenhouse gases is only producing more, it nullifies the efforts of the other countries. Coal is much cheaper energy than alternative energy. Those that use it will have an economic advantage.