The new pipeline, opposed by Native American tribes, would increase the flow of Canadian tar sands crude oil, a contributor to climate change.

In a unanimous decision, state regulators in Minnesota approved a controversial new pipeline that will increase the flow of tar sands crude oil from Canada to refineries in the United States.

The long-anticipated ruling is a victory for Canadian pipeline owner Enbridge and a significant blow to environmental and Native American advocates who opposed the pipeline through northern Minnesota in a region rich in wetlands and wild rice lakes.

The “certificate of need” granted Thursday by the state’s Public Utility Commission greenlights a replacement for Enbridge’s Line 3, a 1,000-mile pipeline that runs from Hardistry, Alberta, to Superior, Wisconsin. The new Line 3 will have an initial capacity about twice that of the current pipeline, and that volume could be increased and also allow for other increases elsewhere in Enbridge’s cross-border pipeline network.