WASHINGTON — A federal judge late Thursday blocked construction of the disputed Keystone XL oil pipeline, saying the Trump administration “simply discarded” the effect the project would have on climate change.
The ruling by Judge Brian Morris of the United States District Court for Montana repudiates one of Donald J. Trump’s first acts as president. Two days after taking office, Mr. Trump signed an executive order approving the Keystone pipeline that had been blocked by former President Barack Obama because of environmental concerns.
In saying that no work can go forward until the government more fully reviews the pipeline’s environmental impact, the ruling tees up another potentially contentious legal battle over climate change with a president who dismisses mainstream science and whose administration is also seeking to block a landmark lawsuit on behalf of children asking the government to stop the rise of planet-warming gases.
The White House did not immediately respond to a request for comment.
Environmental groups hailed the decision as a major victory in the long-running battle over Keystone, which has spanned more than a decade and become a symbol of the political battle over climate change. The nearly 1,200-mile pipeline from TransCanada Corp. would carry about 800,000 barrels of petroleum a day from the Canadian oil sands to Gulf Coast refineries.
TransCanada did not respond to a request for comment. Construction could have begun as early as next year.
“Keystone XL would be a disaster for the climate and for the people and wildlife of this country,” Jackie Prange, senior attorney at the Natural Resources Defense Council, said in a statement Thursday.
Judge Morris found that in reviving Keystone, the Trump administration did not adequately account for how a decline in oil prices might affect the pipeline’s viability. In addition, the government’s analysis did not fully study the potential for oil spills or the cumulative effects of greenhouse gas emissions from the Keystone pipeline in combination with a pipeline approved in 2009, the Alabama Clipper.
The ruling specifically takes the Trump administration to task for failing to address the Obama administration’s arguments about climate change, including the need to keep rising global temperatures at safe levels as a basis for denying the pipeline permit.
When Mr. Obama rejected the Keystone permit in 2015, he was weeks away from negotiating an international global warming accord in Paris, and the administration also argued the pipeline would undercut United States leadership in curbing global reliance on fossil fuels.
The Trump administration failed to present facts or a “reasoned explanation” to those arguments as required, Judge Morris wrote.
Rather, the government had declared that it was embracing a policy shift toward “energy security, economic development and infrastructure” and noted that there had been “numerous developments related to global action to address climate change.”
The judge said an administration had the right to reverse a previous policy, but still must back up its reason for doing so with facts. The Trump administration did not do that, Judge Morris found.
“The Department instead simply discarded prior factual findings related to climate change to support its course reversal,” he wrote. He cited a United States Supreme Court ruling that noted, “An agency cannot simply disregard contrary or inconvenient factual determinations that it made in the past, any more than it can ignore inconvenient facts when it writes on a blank slate.”
The Trump administration or TransCanada could appeal Judge Morris’s ruling to the Court of Appeals for the Ninth Circuit.
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Lisa Friedman reports on climate and environmental policy in Washington. A former editor at Climatewire, she has covered nine international climate talks. @LFFriedman