CANCUN, MEXICO -- North American native groups urged the United States and Canada to abandon support for carbon-heavy oil sands in one of the first visible protests at the UN climate talks in Cancun.

They regard the booming oil sands industry in Alberta as the main reason for Canada's reluctance to embrace stronger greenhouse gas reduction targets and its failure to meet its Kyoto commitments. The U.S. is the largest purchaser of the Canadian crude.

The indigenous groups are particularly concerned over the possible U.S. approval of a 1,700-mile cross-border pipeline known as the Keystone XL. The project, proposed by TransCanada, would eventually pipe 900,000 barrels of oil sands crude each day from northern Alberta to refineries in Texas and tankers off the Gulf Coast.

The pipeline permit has become a focus of attention among U.S. lawmakers especially since the BP Gulf of Mexico oil disaster heightened concern over environmental security. The Keystone XL line would cut through the largest underground aquifer in the U.S. vital to agriculture and population centers in the region and crisscross the lands of several Native American tribes.

The U.S. EPA has criticized the State Department's environmental review of the project as inadequate, creating an inter-agency tussle that has delayed a permit decision into next year. TransCanada, the energy infrastructure company that wants to build the pipeline, has defended the State Department's review of the project as thorough and complete.

"We're here to place pressure on the U.S. for the Keystone XL project and on Canada to actually take a stand on climate change," Jasmine Thomas of the Carrier First Nation in British Columbia told SolveClimate News.

The demonstrators greeted climate negotiators from some 200 nations as they passed through security at the Cancun conference hub.  A handful of police kept an eye on the protests, as a few dozen curious passersby gathered to watch and grab fliers.

The tribes said they came to the UN Framework Convention on Climate Change (UNFCCC) summit for a shot at being heard.

'No Response from U.S.'

"We did not get a response [to our concerns] from the United States government," said Casey Camp-Horinek of the Ponca Nation of Oklahoma, one of the tribes that would be affected by the pipeline.

"We feel as if taking it to another level — where we do have a voice — would give us a better chance," she told SolveClimate News.

Oil sands production involves mining and extracting tarry bitumen out from under Alberta's boreal forests. The U.S. EPA says that on a "well-to-wheels" basis the heavy oil extracted is 82 percent more carbon intensive than conventional oil. The agency's estimate sits in a middle ground between widely varying claims surrounding the oil sands' carbon footprint offered by industry and environmentalists.

Water pollution is a separate concern. Recent research from the University of Alberta found elevated levels of 11 toxic elements in the oil sands' main water source, the Athabasca River.

Camp-Horinek said "there is already a web of pipelines under the ground" in her native Oklahoma from oil refineries that is bringing spills and damaging the quality of air and water with "virtually no regard for any emergency situations."

"The Keystone XL pipeline is not needed or wanted," she said.

A spokesperson for TransCanada told SolveClimate News that there is a need for the pipeline, which would also bring billions of dollars into the U.S. economy and create thousands of construction jobs.

"The crude oil we would transport is needed to replace dwindling supplies of crude at Texas refineries,"  James Millar said via email. "Supplies from Mexico and Venezuela are declining so the refiners need to replace that supply and they want to do it with Canadian crude."

Canada Acts Quietly

The two dozen protesters delivered their message wearing T-shirts that spelled out the words "Shut Down the Tar Sands."  

Canadian environmentalists at the talks said they do not expect their demands will be heeded. There was no official reaction to the protests.

They point to evidence that the government of Prime Minister Stephen Harper is quietly trying to block any climate change policies that would make it more difficult to market oil sands to the world.

Emails obtained by the Pembina Institute think tank and Climate Action Network (CAN) Canada under Access to Information Act requests seem to support that claim.