U.S. President Barack Obama : Leaders will work together on climate change . At Italy summit , leaders pledge to slash greenhouse gas emissions . Leaders pledge aim to achieve a 50 percent reduction in global emissions by 2050 . He called the commitment of the emerging economies `` an important stride forward '' in minimizing climate change , but acknowledged that the issue he called one of the most challenging of our times would be difficult to confront . Summit takes place in heart of disaster zone where about 500 people died .
U.S. President Barack Obama : Leaders will work together on climate change . At Italy summit , leaders pledge to slash greenhouse gas emissions . Leaders pledge aim to achieve a 50 percent reduction in global emissions by 2050 . Summit takes place in heart of disaster zone where about 500 people died .