#3. The Green Supply Chain

In the age of the international conglomerate, business may have the ability to create more radical change than any single government. A $180 billion company like Wal-Mart has ties to tens of thousands of smaller companies around the world, and through the power of sheer size, it can all but force those suppliers to sell their goods cheaper — or, if Wal-Mart wishes, greener. That's exactly what the Bentonville retailing giant has done this year, pressuring its suppliers to go green. Wal-Mart's initiative was followed this October by the launch of the Supply Chain Leadership Coalition, in which some of the biggest companies in the world — including Procter & Gamble and Unilever — banded together to press suppliers to report their greenhouse-gas emissions and be more open about their efforts to combat climate change.