President Barack Obama and Chinese President Xi Jinping have entered in a joint agreement to lower carbon dioxide emissions in the United States and China.

To meet the new target goal of reducing emissions 17 percent by 2020, the pace will have to double, according to a White House press release.

China and the U.S. are the largest producers of greenhouse gases, and make up 45 percent of the world’s carbon emissions.

Conversations for a new standard of greenhouse gas emissions have been going on for several months. China has agreed to generate 20 percent to its electric power from renewable sources by 2030 or earlier. This is the first time China has agreed to cut back on carbon emissions.

The two presidents hope their sustainable initiative will encourage other countries to follow suit.

Implementing the joint agreement will be difficult for President Obama, who has no more than two years left in office. Republicans have already voiced their opposition for the new target goal.

“This unrealistic plan, that the president would dump on his successor, would ensure higher utility rates and far fewer jobs,” Mitch McConnell, senate minority leader, said in a statement released by his office.