Once again, environmental groups are trying to use the courts to halt a $9.3-billion pipeline project that they say poses a threat to endangered southern resident orcas.

Ecojustice, the Living Oceans Society, and Raincoast Conservation Foundation filed documents today in the Federal Court of Appeal.

They're seeking a judicial review of the Trudeau cabinet's decision to re-approve the Trans Mountain pipeline expansion.

In court, the environmental groups have alleged that the feds failed to comply with their responsibility to protect these creatures.

“The population of southern residents is small and declining, and the decline is expected to continue," Raincoast senior scientist Paul Paquet said in a news release. "In order to recover, these imperiled killer whales need urgent support, not an increase of physical and acoustical disturbances, oil spills, and contaminants associated with more tanker traffic."

He described the federal government's "failure" to fulfill its responsibility to these creatures as "emblematic of the disarray and apparent political neglect in the government’s endangered species policy".

In May, the federal government announced new rules requiring vessels to remain at least 400 metres away from southern resident orcas. Commercial whale-watching ships are allowed to venture within 200 metres.

Meanwhile, the pipeline project will result in a large increase in oil tanker traffic in the Salish Sea.

The media often characterize this as a seven-fold rise to around 400 tankers per year in Burrard Inlet.

However, Burnaby North—Seymour NDP candidate Svend Robinson has insisted that it's more than a 10-fold increase.

That's based on actual tanker traffic arriving and leaving Westridge Terminal in Burnaby over the previous two years.

In today's news release, Ecojustice's nature program director, Margot Venton, emphasized that the pipeline project was re-approved after Parliament had declared a climate emergency. 

"We simply can’t afford to build a project that will increase emissions at precisely the moment the science says we need to dramatically reduce our carbon footprint to avoid climate breakdown,” she said.

Documents filed by the City of Vancouver to the National Energy Board suggested that the Trans Mountain pipeline expansion would result in annual emissions of71.4 megatonnes of carbon dioxide equivalents. That exceeds yearly emissions across British Columbia.

Karen Wristen, executive director of the Living Oceans Society, highlighted the impact of rising carbon emissions on ocean acidification.

"The prime minister tells us he’s taken into account the emissions caused in Canada by mining the tar sands, but it’s clear that the impact of burning that oil over the next 50 years hasn’t been taken into account in approving this project," she insisted. "It will drive ongoing acidification of the world’s oceans to new levels at which the survival of marine life becomes questionable.

"The climate isn’t going to take notice of whose emissions tip it over into a state of cascading and unpredictable change: we are all responsible and we are all at risk.”

According to Orca Network, there are 76 southern resident orcas living in three pods. A 77th orca is being kept in captivity at the Miami Seaquarium.