A US federal judge has upheld the Biden administration’s approval of ConocoPhillips’ Willow oil project in the National Petroleum Reserve in Alaska (NPR-A), thereby allowing the drilling project in the Western Arctic to move ahead.

The ruling by US District Judge Sharon Gleason is in response to a lawsuit filed in March 2023 by Earthjustice on behalf of Defenders of Wildlife, Friends of the Earth, and Greenpeace USA, along with the Center for Biological Diversity and Natural Resources Defense Council.

The environmental groups have been contending that the Department of Interior’s approval to the oil drilling project did not meet the stipulated federal legal requirements.

Judge Gleason rejected the groups’ assertions and determined that the federal environmental analysis supporting the project’s approval is robust. The judge’s decision means ConocoPhillips can begin construction this winter on Alaska’s North Slope as per schedule.

However, the environmental groups declared their intent to challenge the court ruling by filing an appeal in the Ninth Circuit.

ConocoPhillips aims to draw 180,000 barrels of oil per day at peak from the Willow oil project, which has been scaled down to three drill site pads from the original number of five.

Earthjustice has been claiming that the oil project would result in carbon dioxide emissions equivalent to driving an additional two million cars for the next three decades. This would cause significant environmental damage to the Arctic, its wildlife, and the local communities that rely on the land for sustenance, said the organisation.

According to Earthjustice, the Willow oil project is projected to contribute nearly 260 million metric tons of carbon emissions to the atmosphere over the next 30 years.

Earthjustice Alaska regional office deputy managing attorney Erik Grafe said: “While today’s ruling is disappointing, we are entirely confident in our claims, and plan to appeal to the higher court.

“Beyond the illegality of Willow’s approval, Interior’s decision to greenlight the project in the first place moved us in the opposite direction of our national climate goals in the face of the worsening climate crisis.”