provided by the frontline journalism fund. and a grant from hannelore and and jeremy grantham and the grantham foundation for the protection of the environment. and additional support from scott nathan and laura debonis. additional funding for heat is provided by the kendeda fund. and the nathan cummings foundation. and wallace genetic foundation, inc. tonight on frontline. we re standing at the precipice of hell. if everybody else was to live like an american, then the planet is doomed. .in the midst of a campaign dominated by economic anxiety. the facts of global warming demand our urgent attention. frontline investigates what will be the most important issue facing our world. we can t wait to solve one of the greatest crises that mankind has ever faced and roll back greenhouse gases and global warming. tonight, correspondent martin smith, travels the planet to uncover the scale of the problem and the scale of any solution. by the year 2050, we need to reduc