Oil pipeline projects had been halted by decisions under Obama administration.

Following up on promises to advance fossil fuels, President Trump signed an executive action today to push forward the Dakota Access pipeline as well as the Keystone XL pipeline.

The Keystone XL pipeline was intended to connect oil (technically diluted bitumen) from the oil sands of Alberta, Canada to refineries and ports on the Gulf of Mexico. The pipeline was strongly opposed by advocates for action on climate change because the processing required to extract useful oil from the thick bitumen makes it an even bigger source of CO2 emissions than usual.

In November 2015, the Obama administration rejected the pipeline after a long period of uncertainty, citing the contribution to climate change and a lack of significant benefits in terms of jobs and US energy prices.

The Dakota Access pipeline was intended to run between the Bakken Shale oil field in western North Dakota and facilities in Illinois, but protests near the Standing Rock Indian Reservation brought national scrutiny to the project. The pipeline was being routed across Lake Oahe (a reservoir behind a dam on the Missouri River) just beyond the boundary of the Standing Rock Reservation.

Following those protests, the Army Corps of Engineers decided not to grant the easement for crossing Lake Oahe and started an evaluation of alternative routes.

Details on how the Trump administration intends to get around these decisions are not yet available.

President Trump has owned stock in Energy Transfer Partners, the company behind the Dakota Access pipeline. Until recently Trump’s nominee for energy secretary, former Texas Governor Rick Perry, sat on the board of directors of Energy Transfer Partners.