US President Barack Obama and his Chinese counterpart Xi Jingping unveiled a significant new deal on reducing carbon emissions to fight global climate change.  The two say they will cut greenhouse gas pollution by up to 28 percent from 2005 levels by the year 2015.

“This is an ambitious goal, but this is an achievable goal,” said President Obama at a joint news conference with Xi Jinping.  “We have a special responsibility to lead the world effort to combat global climate change.”

Until today, the two nations were unable to reach an accord because of the “you first” syndrome – neither would make deep cuts to greenhouse gas emissions until the other did.

Now, China is for the first time agreeing on a peak emissions date, in 2030.  That means that China’s carbon emissions will likely increase in the next 15 years, but now there is a first-ever commitment from Beijing on when to stop.  The US would nearly double its pace of carbon reduction from 1.2 percent to 2.3 percent per year through 2020.  That would deepen to 2.8 percent a year afterward.

China’s vow takes away the chief sticking point of US Republicans who’ve thus far blocked climate legislation in Congress.

“The biggest carbon polluter on our planet, China, has agreed to cut back on dangerous emissions, and now we should make sure all countries do their part because this is a threat to the people that we all represent,” said Senator Barbara Boxer of California, outgoing chair of the Senate Environmental and Public Works Committee.

China and the US account for over one third of all global greenhouse gas emissions.  The two nations remain a step behind the European Union, which earlier this year committed to reduce its emissions by at least 40 percent below 1990 levels by 2030.