China is planning to build as much as 40 massive projects to convert coal to synthetic natural gas (SNG) as it zealously works to curb it coal pollution emissions. But a group of researchers had strongly warned it best to all together shelve the project because the SNG plants will greatly increase China's greenhouse emissions, releasing yet another environmental disaster.

A study by researchers from Duke University said China's SNG plants, still powered by coal, will produce seven times more greenhouse gas emissions than conventional natural gas plants. It also risks to use up to 100 times the water as shale gas production.

"Using coal to make natural gas may be good for China's energy security, but it's an environmental disaster in the making," Robert Jackson, environmental science professor at Duke, said.

"At a minimum, Chinese policymakers should delay implementing their synthetic natural gas plan to avoid a potentially costly and environmentally damaging outcome," researcher Chi-Jen Yang added. "An even better decision would be to cancel the programme entirely."

China has so far approved nine SNG projects that are expected to produce 37.1 billion cubic metres (1.31 trillion cubic feet) of SNG annually. If burned to generate electricity, SNG's carbon emissions is 82 per cent greater than a coal-fired power plant. Moreover, tailpipe emissions from a SNG-powered vehicle compared to a conventional car are twice as much.

These nine SNG plants have an expected life span of 40 years. Over those years, researchers surmised the carbon dioxide (CO2) emissions of these nine plants alone will reach 21 billion tonnes, compared to the measly three billion tonnes of a "natural" gas plant.

Doing further Math, if China pushes to contruct all planned 40 SNG plants, their total CO2 emissions would reach as high as 110 billion tonnes over 40 years. In 2011, China's total CO2 emissions reached 7.7 billion tonnes.

"The increased carbon dioxide emissions from the nine government-approved plants alone will more than cancel out all of the reductions in greenhouse gas emissions from China's recent investments in wind and solar electricity," Yang said.

"While we applaud China's rapid development in clean energy, we must be cautious about this simultaneous high-carbon leapfrogging."