In the group’s latest Vital Sign report research fellow Christoph von Friedeburg concludes that shale gas production has some troubling external factors

Shale gas is produced in the US, Canada, and China, and discussions about fraccing are ongoing in several European countries, including Australia, Germany, the UK and Bulgaria, with their being around 7299 trillion cubic feet of shale gas considered technically recoverable today, a figure that could rise or fall with further exploration work, but Worldwatch says recoverable quantities of shale gas across the region remain uncertain.

Many supplies are located deep underground, some in densely populated areas which may not be developed, while in areas such as Europe there are disputes about the ownership of mineral rights, and substantial environmental and safety concerns.

The UK government appears to be in favour of shale gas development. However, the single shale well that has been fracced in the country so far, in 2011, caused two small earth tremors, leading to a temporary ban on fraccing that was in effect until 2012.

Since then, a handful of exploration wells have been drilled, but none have been fracced.

In Romania, expectations for the country's shale gas future have soured because of lower and less-profitable projections of available reserves, growing public opposition to fraccing, and lower oil prices, which have rendered natural gas less economically viable.

China has invested more than $US1 billion in shale gas exploration so far, but most of the country's deposits are in hard-to-access mountainous areas, either at great depths or too far from the considerable water resources required for the fraccing process.

This makes drilling wells, as well as establishing the needed infrastructure, such as roads and pipelines, more challenging and expensive.

The US is by far the dominant producer of shale gas, producing a record 32.9 billion cubic feet per day in 2014.

Proponents of fraccing have touted shale gas development as a boon for local job creation. However, Worldwatch says most of the associated jobs are temporary, and many are filled by out-of-area workers whose short-lived influx provides only passing benefit to local economies.

The development of clean, renewable energy sources, such as wind and solar, has been shown in many cases to be more successful in creating employment, von Friedeburg said.

Worldwatch says the costs of damages to local roads from the heavy-truck fleets needed for well construction and wastewater transport amount to hundreds of millions of dollars.

“Air pollution emissions from vehicles and from well-pad diesel generators can harm human health; and the toxic waste water that flows out from the wells after the fraccing fluid is pumped underground-containing a mixture of chemicals, water, and sand-is often inadequately treated, presenting a danger to soils and aquifers," it said.

"Such impacts need to be assessed closely within the US as well as in other countries that are considering shale gas development.”

The group is concerned about the sheer number of shale gas wells being drilled, because while the gas has a short-term displacement effect, replacing dirty coal with cleaner natural gas, the long-term, global benefit of this reduction is dubious given the fraccing process can release large quantities of methane.

Further, growing amounts of US coal have found their way to export markets, increasing overall global greenhouse gas emissions.