But the agency, which law requires to divulge climate concerns, said “the large magnitude of climate change effects” would be “likely to overshadow smaller magnitude impacts of oil development.” The extinction of scores of bird species could happen “with or without oil leasing and development.”

ADThe refuge — home to polar bears, wolves, migratory birds and the Porcupine caribou herd — has long been closed off to oil and gas exploration despite long-standing interest among members of the petroleum industry. Climate change has made the area more delicate as melting ice has driven threatened polar bears to spend more time in dens along the refuge’s coastal plain.

In filing a final environmental impact statement, the Interior Department’s Bureau of Land Management (BLM) took a key step closer to holding an oil and gas lease sale for the nearly 1.6 million-acre coastal plain, which is part of the 19.3 million-acre ANWR.

But Trump's signing of the bill was partially overshadowed by environmentalist groups angered that his proposed federal budget cuts funding by 31 percent for the U.S. Environmental Protection Agency, or EPA. His proposed budget also reduces funding for the U.S. Department of the Interior by 14 percent and completely eliminates a $7,500 tax credit given to owners of electric vehicles. Additionally, the president named a former coal lobbyist, Andrew Wheeler, as head of the EPA.

The bill was touted by Mojave Desert conservationists and also created a new national monument in honor of 431 people who were killed during the 1928 collapse of the St. Francis Dam near Santa Clarita, California, close to Los Angeles.

The lands package bill included the Wild and Scenic Rivers Act, which protects 30,000 acres of old-growth rainforest and 250 miles of waterways along Oregon's coastline.