The move is part of a bigger push by the U.S. retailing giant that aims to remove 1 billion tonnes of carbon dioxide from its global value chain by the end of 2030, equivalent to taking 211 million vehicles off roads for a year.

Walmart said it had created a specific programme for China that would begin with around 100 major Chinese suppliers and provide tools to measure emissions and set targets.

"We are working with our suppliers on areas such as energy efficiency, renewables, packaging, waste reduction, and thinking about areas like deforestation and improving energy efficiency," said Laura Phillips, senior vice president for sustainability.

The company aims to eventually expand the programme to its entire China supply chain.

Walmart has already enrolled 800 Chinese factories into an energy efficiency programme launched in 2014, helping them cut costs by $40 million a year, said Bill Foudy, Walmart's China-based vice president for global sourcing.

"It is often misunderstood that energy efficiency costs money, when we've found it to be the opposite," he said.

China, the world's biggest producer of greenhouse gas, aims to cut its energy intensity - or consumption per unit of economic growth - by 15 percent over the 2016-2020 period.

The country aims to bring carbon emissions to a peak by "around 2030". It said this week that a target to cut carbon intensity by 40 percent to 45 percent over 2005-2020 had been met three years early.

(This version of the story corrects headline and first paragraph to show aggregate emissions to be cut, not annual emissions.)

(Reporting by David Stanway; editing by Richard Pullin)