Australia is a step closer towards building one of the world’s largest coal mines, despite years of lobbying from environmentalists who worry such a project will undermine efforts to combat climate change and threaten one of the most imperiled ecosystems on the planet, the Great Barrier Reef.

The $16 billion Carmichael coal mine will, if completed, cover more than 100 square miles in the state of Queensland. At its peak, about 44 million tons of coal will be wrenched from the earth each year and shipped to India, enough to power 100 million homes.

But both scientists and activists have expressed worry that the project, centered around the dirtiest fossil fuel, will only contribute more to climate change and continue Australia’s legacy of being one of the biggest emitters of greenhouse gases per capita in the world.

“It is kind of perplexing, really,” said Shani Tager, a reef campaigner for Greenpeace Australia. “With the Paris climate agreement and the targets that we’ve signed up to internationally, [the Carmichael coal mine is] clearly not going to help [halt climate change].”

The phenomenon is by far the greatest threat to the Great Barrier Reef, which just suffered through the worst coral bleaching event in recorded history. Australia has pledged to do all it can to protect the reef as such events are expected to hit more often and become more severe as the world warms.

Saeed Khan/Getty Images The Carmichael coal mine has cleared most regulatory hurdles and received conditional funding for a railway from the Australian government.

Last month, Australia ratified the landmark Paris climate agreement, meant to keep the planet from warming more than 2 degrees Celsius, beyond which scientists have said the globe will suffer the worst effects of climate change. The primary cause of the temperature increase is greenhouse gas emission from fossil fuels. The country’s plans to build the coal mine seem to run contrary to the latest coal project, detractors say.

“I listen to the reef scientists who say we are at a crossroads and we have to choose between new coal and the future of the Great Barrier Reef,” Larissa Waters, deputy leader of Australia’s pro-environment Green party, told HuffPost Australia. “I’m on the side of the 70,000 people who need the reef healthy for their job and I’m on the side of future generations who will not believe we were willing to sacrifice this natural icon.”

The Carmichael mine, spearheaded by India’s Adani Enterprises, has been in the works for more than six years and faced a slew of setbacks. Banks have declined to invest in the project, environmental groups have launched lawsuits and researchers have warned several endangered species could be under threat.

But the project recently cleared most of the regulatory hurdles needed to proceed, and the Australian government has conditionally approved a $750 million loan to help build a railway to transport the coal to a shipping terminal near the Great Barrier Reef.

Government officials have said the project won’t impact the reef ― citing some 39 approval processes and environmental assessments ― and will create thousands of domestic jobs.

“The coal will be mined in regional Queensland by regional Queenslanders,” Annastacia Palaszczuk, the state’s premier, said at a press conference. “Jobs will return to these small regional mining communities.”

The CEO of Adani, Jayakumar Janakaraj, said the project will actually be a “net positive impact on climate change in the world.”

“If Australia doesn’t produce and give India high-quality, highly sustainable mining, it’s going to rely on coal that will come from less reliable geographies,” he told Reuters.

But scientists are doubtful. Terry Hughes, director of the ARC Centre of Excellence for Coral Reef Studies, said claims that the project will have positive impacts on the reef are “laughable.”

“We can’t restore the Great Barrier Reef if we allow fossil fuels to destroy it,” he wrote on Twitter.

Put more simply:

It's not complicated - they dig up #coal to burn it, which causes #globalwarming, which kills corals. https://t.co/ULtrFgBFYX — Terry Hughes (@ProfTerryHughes) December 5, 2016