U.S. President Barack Obama : Leaders will work together on climate change . At Italy summit , leaders pledge to slash greenhouse gas emissions . However , Stern said the 2-degree threshold was the `` underpinning '' of the global goal for an overall 50 percent reduction in greenhouse gas emissions by 2050 , including the 80 percent cuts targeted by the G-8 countries . Leaders pledge aim to achieve a 50 percent reduction in global emissions by 2050 . Comment:
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 . Comment: