America and China agreed on Wednesday to work together to develop cleaner trucks, expanding joint efforts against climate change by the two greatest emitters and raising prospects for a global climate deal.

The new initiatives announced in Washington on Wednesday would see China and the US extend their climate co-operation to five new areas – beginning with heavy trucks, which are a significant cause of greenhouse gas emissions in both countries.

The US secretary of state, John Kerry, speaking before the announcement, said such co-operation would resonate far beyond the two countries, boosting prospects for a global climate agreement.

America and China between them account for more than 40% of greenhouse gas emissions, but signs of co-operation between the two big emitters could help unlock a global deal to cut emissions, Kerry suggested earlier on Wednesday.

"I want to underscore that when we make a decision … it ripples beyond our borders," Kerry said. "How will we curb climate change? How will we pioneer new energy technology that is in fact the solution to climate change?" Kerry said in his opening remarks at the fifth annual US-China Strategic and Economic Dialogue.

A State Department fact sheet on the new initiatives underlined Kerry's point, noting that the two countries pledged to work together to advance the United Nations' efforts to reach an international climate accord.

"Recognising the importance of working through the United Nations Framework Convention on Climate Change (UNFCCC), the United States and China are committed to enhancing our policy dialogue on all aspects of the future agreement," the fact sheet said.

That spirit of co-operation represents a drastic change from the calamitous Copenhagen climate summit in 2009, when diplomatic snubs and general distrust between the two countries wrecked any prospect for a deal.

The State Department climate envoy, Todd Stern, told reporters he thought the initiative would help efforts to reach a deal by 2015.

Under the initiatives announced on Wednesday, the two countries agreed to work together to reduce emissions from heavy duty trucks and other vehicles by raising fuel efficiency standards and introducing cleaner fuels.

The State Department notes in its fact sheet that emissions from transport account for a significant share of China's notorious air pollution.

The countries also agreed to work together to develop carbon capture technologies, increase energy efficiency in buildings, promote smarter grids and improve reporting of greenhouse gas emissions.

The working groups for each initiative are to report back in October, the State Department said.

The announcement marks the second agreement on climate co-operation between America an China in a month following the agreement in California between Barack Obama and China's premier Xi Jinping to work together to reduce the production of especially powerful climate pollutants – hydrofluorocarbons. HFCs are used in air conditioners and refrigerators and are far more potent than carbon dioxide in the short-term.

That deal – followed one week later by Obama's announcement of a sweeping climate change plan – appeared to have eased the way for further co-operation between America and China, said Deborah Seligsohn, who has advised the World Resources Institute on China's climate and energy policies.

Obama's plan would bypass Congress to use government agencies to cut emissions from power plants and take other climate measures.

Seligsohn said the move could prod China towards more ambitious curbs on its own greenhouse gas emissions at future negotiating rounds.

"There is a little bit of new wind in everybody's sails right now," she said.