A federal appeals court has dealt a setback to environmentalists trying to force the Interior Department to reconsider the climate impacts of its coal leasing program, one of the world’s biggest sources of global warming pollution.

The U.S. Court of Appeals for the District of Columbia Circuit ruled that the department was under no obligation to redo the program’s environmental impact studies, which were conducted four decades ago when the science of climate change was in its infancy.

But the ruling was a narrow one. The three-judge panel, in a unanimous decision written by Judge Harry Edwards, said the activists can continue to challenge individual leases on climate grounds under the National Environmental Protection Act (NEPA), an avenue where they have met some successes in lower courts.

At issue is one of the most disputed fossil fuel programs on public lands, especially in the West, where federal subsidies drive gigantic quantities of coal onto the market.

Scrapping an Obama-Era Coal Lease Moratorium

Just before the end of the Obama administration, the Interior Department put a moratorium on new leases and  announced a major reconsideration of the program’s merits, including a comprehensive new environmental impact statement that would have addressed the climate questions head on.

But the Trump administration scrapped that approach as part of its full-bore attempt to salvage the coal industry, which has been collapsing in the face of environmental regulations and competition from cheaper, cleaner sources of energy.

That put the coal leases back on track without any significant consideration of how the resulting emissions of carbon dioxide affect Earth’s climate.

It’s a glaring problem that the Trump administration is determined to keep on the back burner, preferably of a coal-fired stove.

Not only does Interior’s Bureau of Land Management continue to write leases with cursory climate assessments, the administration has canceled Obama-era instructions to agencies telling them how to comply with NEPA’s requirements when considering climate impacts.

1979 Statement Mentioned CO2 Risk

At the heart of NEPA is its requirement for a “hard look” at the broad, cumulative environmental impacts of major federal actions. But in 1979, Interior gave the nascent climate science a glance, but little more.

The 1979 environmental impact statement for the coal leasing program acknowledged that “there are indications that the rising CO2 levels in the atmosphere could pose a serious problem, commonly referred to as the greenhouse effect.” But it cited uncertainties in the science and called merely for further study of any impacts from coal mining.

The plaintiffs in this case, the Western Organization of Resource Councils and Friends of the Earth, pointed out in court that there have since been tens of thousands of peer-reviewed scientific studies and that the implications are clear: the use of coal ought not to proceed unchecked as emissions continue to mount and warming reaches calamitous levels. They argued that NEPA requires a new look at the problem, given the passage of time and the advance of science.

But citing a 2005 Supreme Court precedent in a wilderness case, the court said a new review would be required by NEPA only if the government were taking an important new action involving the coal leasing program—not merely maintaining it. Since there is no big change in the program, the court found, no new impact statement is required.

Judge Suggests 2 Paths for New Reviews

Still, in a few sympathetic passages, Edwards acknowledged that the environmentalists’ case was “not frivolous.”

Given that the science has demonstrated that “coal combustion is the single greatest contributor” to climate change, he said, and that the evidence was not so strong when the coal leasing program first passed NEPA review, coal’s foes “raise a compelling argument” for a fresh look.

He suggested two possible paths: They could petition Interior Secretary Ryan Zinke, who does not embrace the mainstream science on climate change, and seek judicial review on the merits if he turns them down. Or they could continue to challenge individual leases that rely on the outdated impact study from 1979, since each new coal lease does constitute a new federal action and must pass scrutiny under NEPA.

The BLM and Friends of the Earth both said they were still reviewing the case and had no further comment for now.