G-8 leaders

President Barack Obama joined other leaders of the industrialized world Wednesday in backing new targets for battling global warming. But the wealthy nations were unable to persuade leaders of developing countries to commit to reductions of their own, and their cooperation is critical to avoiding the worst effects of climate change.

White House officials confirmed that Obama agreed to language supporting a goal of keeping the world's average temperature from rising more than 2 degrees Celsius (3.6 degrees Fahrenheit).