As scientific researchers continue to press for a reduction in oil sands development across North America, tribes such as the Uinta Ouray Ute Tribe could face hard decisions as oil sands development comes knocking.

More than half of the known United States oil sands reserves occur in two areas of Utah: the Uinta Basin to the northeast, and an area in the central southeast. Within these areas are more than 50 identified oil sands deposits that contain a potential total of 20 to 32 billion barrels of oil, according to an estimate by U.S. Oil Sands, the Canada-based company preparing to mine it. One of its prize project areas, PR Springs, straddles the border between state lands and the Uinta Ouray reservation.

Fracking has been occurring on the reservation since the technology was developed, but so far, oil sands extraction akin to that practiced in Alberta, Canada, is just a controversial proposal, according to tribal member Forrest Cuch.

Oil sands extraction involves the separation of tarry, oil-containing bitumen from sand and clay. It is a cousin to oil shale development, wherein oil is separated as a liquid from heated sedimentary rock. Both types of extraction are occurring, albeit on a small scale, on areas just outside the Uinta Ouray reservation.

The tribally controlled part of the reservation, about 1.2 million acres, includes about 500,000 acres that were given back to the tribe by the federal government in the late 1980s. Called the Southern Extension, the acreage includes desert-to-mountain terrain in the Book Cliffs area between Price, Utah, and Grand Junction, Colorado.

“The first thing the tribe did was declare a third of it forever wild,” Cuch said. “I’ve always been proud of that. But now there’s pressure to develop it. It’s motivated by greed and money. It’s created some struggle here.”

Cuch is adamantly opposed.

“It’s terribly dirty and polluting,” he said. “I think our tribe needs to take a strong position and constantly hammer that position.”

The tribe has not commented officially. Members of the tribe’s governing body, the Ute Business Committee, did not return numerous phone calls and e-mails from Indian Country Today Media Network. But in June the Ute joined a lawsuit filed by four states against the U.S. Department of the Interior calling new fracking rules too restrictive, according to the Associated Press.

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Cuch’s perspective puts him on the same side as groups like Peaceful Uprising and Utah Tar Sands Resistance, whose activists have camped out near some of the operations and occasionally gotten arrested for disrupting the work, as the Salt Lake Tribune reported in June 2014.

“This stuff needs to stay in the ground,” said John Weisheit, conservation director of the Moab-based group Living Rivers, which has also been fighting the development attempts. “It is too dirty to process. It’s too energy intensive to process. It requires way too much water. Why are we putting or water air and climate at risk for fuels that don’t have a lot of value?”

Recent events up in Alberta lend credence to the dirtiness of it all. The biggest spill in Canada’s history sent 1.3 million gallons of emulsion—a mixture of water, crude and sand—into the muskeg.

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Weisheit’s sentiment is echoed in the scientific community. In a rare consensus, more than 100 scientists issued a petition on June 10 calling for a halt to new oil sands development in North America.

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Canadian oil sands extraction is happening largely in northern Alberta and to some extent east of the Rockies, in boreal and sub-boreal forests, said Ken Lertzman, a forestry professor at Simon Fraser University in British Columbia and one of the petition signatories. And that has implications for many indigenous people, he said, expanding on the researchers’ reasons for suggesting the moratorium.

“Once you get more than 100 miles or so north of the border, a lot of the communities are indigenous communities,” he said, “especially in the more remote part, a lot of small, remote communities that are essentially trying to maintain a balance between traditional lifestyles and generating income and that kind of thing.”

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Besides posing a dilemma for Native people, such development comes with myriad consequences, he noted.

“The landscape is crisscrossed with seismic lines,” Lertzman said, referring to the noisy apparatus that is set up to measure oil deposits. “There’s disturbance to caribou, threatened species, impacts ecologically as well as culturally. Once they start trying to extract, it’s basically like strip mining.”

In addition, the processing of the crude requires copious amounts of water and “creates an area of intense disturbance where the intent is that it will be rehabilitated and restored,” Lertzman added. “But we don’t have any examples where they have done that.”

Similarly, he said, the process leaves tailing ponds that are often situated above groundwater supplies or near streams, and the intent is to detoxify those—once they figure out how.

“It’s basically a research project at this point as to how they will be able to do that,” Lertzman said.

As Indigenous Peoples worldwide grapple with climate change’s effects, the debate over expanding oil sands development intensifies, Lertzman noted.

“There is overwhelming evidence that subsistence communities around the world are already seeing many, many kinds of changes in weather, currents and ecological responses of plants and animals,” he said. “I think a lot of people recognize that if we’re going to make a difference on the global front in terms of reducing emissions, we can’t be expanding these dirty, expensive sources of oil.”