A major fossil fuel project in the Arctic is experiencing delays due to shrinking ice cover—an ironic consequence of climate change that is transforming the frozen landscape.

The project is slated to become the first oil and gas production facility in federal Arctic waters, and advanced under the pro-energy Trump administration. Last month the Interior Department issued conditional approval to Texas-based Hilcorp Energy to build an offshore production facility in the Beaufort Sea, which borders Alaska’s northernmost coast, just miles from the Arctic National Wildlife Refuge.

If developed, the groundbreaking “Liberty Project” would consist of a nine-acre artificial gravel island with a pipeline to the shore, roughly fives miles off the shallow coast and 20 miles east of Prudhoe Bay, one of the largest oil fields in North America. Hilcorp estimates that it could recover 150 million barrels of crude oil from the reservoir.

But construction of the gravel island is being hampered by warming Arctic waters, Alaska Public Media first reported. Unseasonably thin ice is preventing Hilcorp from progressing at the pace it originally intended.

“In my opinion, this is related to climate change,” Mark Serreze, director of the National Snow and Ice Data Center, told Motherboard in an email.

Hilcorp aims to use landfast sea ice, which forms along the coastline, as a foundation for the island—removing sections of ice, pouring gravel through to the seafloor, and laying concrete on top, “building the island structure from the bottom up,” stated a plan the company’s submitted in 2015 to the Interior’s Bureau of Ocean Energy Management (BOEM). This technique has been used by fossil fuel projects elsewhere in the Arctic.

Landfast sea ice is mostly stationary and accumulates in shallow waters off the coast, thickening in the fall and breaking up come spring. Its behavior can be an indicator of climatic changes in the Arctic for scientists anticipating how these shifts will disrupt the region’s interconnectedness.

“Hilcorp originally estimated in 2015 that it would take one year for island construction,” a BOEM spokesperson told Motherboard in an email.

This ice needs to be thick enough to safely transport building materials, the spokesperson added. But over the last few years, “that thickness has not developed until unusually late in the season.”

As a result, Hilcorp has tacked another year onto its construction timeline.

And while sea ice conditions can be highly variable, “there has been a trend over the past few decades, clearly associated with climate change, towards much more open water at summer's end in the Beaufort Sea and a later autumn freeze up,” Serreze said.

“The freeze-up is later because there is now more heat in the upper ocean at summer's end than there used to be, and before ice can form in autumn, the ocean has to lose that heat to the atmosphere,” Serreze explained. “With ice forming later, it is only later in this season that it can become thick enough to safely traverse with heavy machinery.”

The Liberty Project was described as a testament to “American energy dominance” by Interior Secretary Ryan Zinke. Meanwhile environmental groups and indigenous communities expressed concern over its threat to local ecosystems and potential oil spills.

Hilcorp boasts a troubling safety and environmental track record, InsideClimate News pointed out. The company has acquired numerous violations, including a 2015 incident when three workers were nearly killed by a nitrogen leak from a well.

In 2015, fossil fuel giant Royal Dutch Shell abandoned its controversial plan to commence exploratory drilling in the Chukchi Sea, also federal Arctic waters. Unlike the Liberty Project’s gravel island, it would have used floating rigs 70 miles off the Alaskan coast.

“Responsibly developing our resources, in Alaska especially, will allow us to use our energy diplomatically to aid our allies and check our adversaries,” Zinke said of the Liberty Project. “That makes America stronger and more influential around the globe.”

But the Arctic’s remote and tempestuous waters are a risky place to drill for oil, even according to the Interior Department’s own assessment. Hard-to-reach locations, foul weather, and a lack of infrastructure would make cleaning up an oil spill prohibitively difficult.

One of former president Barack Obama’s final acts in office was to withdraw large swaths of the Beaufort and Chukchi seas from new offshore oil and gas drilling. President Trump later moved to lift that ban.

Warming temperatures around the Arctic are affecting other fossil fuel projects, too, disrupting machinery that’s been calibrated to operate in colder weather.