Historic step expected to get more countries to agree on deal in 2015

China and the United States made an unprecedented joint pledge on Wednesday to cut greenhouse gas emissions, a historic step that is expected to drive more countries on board to negotiate a new agreement in Paris next year.

China announced it intends to achieve peaking of carbon dioxide emissions around 2030 and to make its best effort to peak early, according to a joint announcement made by President Xi Jinping and US President Barack Obama in Beijing on Wednesday.