SYDNEY ― An Indian mining giant announced Tuesday the “official start” of a proposed $16 billion coal project in Australia that conservationists say threatens the Great Barrier Reef.

Adani Group chairman Gautam Adani said the company had approved its “final investment decision” regarding the controversial project in central Queensland. The 100-square-mile Carmichael mine would produce millions of tons of the fossil fuel each year.

It has faced severe backlash in the country from environmental groups who say the project would negate Australia’s pledges to limit greenhouse gas emissions and harm the environment ― particularly the imperiled reef, located off the state’s coast.

“We have been challenged by activists in the courts, in inner city streets, and even outside banks that have not even been approached to finance the project,” said Adani, who founded the energy company, at a press conference. “We are still facing activists. But we are committed to this project.”

In recent months, Australian officials have cleared regulatory hurdles for the project and the federal government announced it had conditionally approved a $750 million loan to help build a rail line to transport coal from the Carmichael mine to a proposed shipping terminal on the coast. At its peak, the mine would produce about 44 million tons of coal annually to ship to India. That’s enough energy to power 100 million homes.

“This is a great day not just for the Queensland economy, but for the Queensland people, and our greatest asset is our people,” said Queensland Premier Annastacia Palaszczuk at a press conference.

Environmentalists and scientists, however, have roundly lambasted the project and said it runs contrary to any efforts to address climate change. Australia is still party to the landmark Paris climate accord and has pledged to reduce emissions 26 to 28 percent by 2030.

“You can’t be the world’s biggest coal exporter and at the same time be taking action on climate change,”said Nikola Casule, a climate and energy campaigner at Greenpeace Australia. “It’s completely incompatible.”

Credit: Greg Torda/ARC Centre of Excellence for Coral Reef Studies Government officials have said the mine wouldn’t impact the Great Barrier Reef, but scientists say we can’t restore the structure if we allow fossil fuels to destroy it.

Casule noted Tuesday’s announcement doesn’t guarantee the mine would be built because Adani has yet to secure enough funding to start the project. Following public pressure, multiple banks have distanced themselves from the mine, saying they would not fund the project. He said Greenpeace was planning to do “everything we can” to fight the project, and said the group would take aim at the tax dollars being proposed to fund it.

“We know Australians don’t want billions of dollars of money going to the Carmichael coal mine,” Casule said. “What is the best way to spend a billion dollars? Is it funding a billionaire’s coal mine or is it for things Australians actually care about.”

Tuesday’s announcement comes as scientists continue to warn about the future of the Great Barrier Reef. The structure has endured back-to-back mass bleaching events that have left large swaths of coral dead, spurred by rapidly warming global temperatures. Climate change remains by far the greatest threat to the reef, and the federal government was this week warned it would need to “urgently step up its efforts” to tackle the phenomenon if it hoped to save the Great Barrier.

“Without a comprehensive and effective national climate plan to reduce Australia’s pollution ultimately to zero, reefs will continue to be threatened,” said Amanda McKenzie, the CEO of Australian nonprofit the Climate Council, on Monday. “The future of the world’s coral reefs hangs in the balance. To protect them for the future means tackling climate change by rapidly and drastically reducing our carbon emissions.

Government officials have said the mine wouldn’t impact the Great Barrier Reef. The Queensland government’s Palaszczuk cited 39 approval processes and environmental assessments when she threw her support behind the project at the end of last year.

Scientists, however, disagree.

“We can’t restore the Great Barrier Reef if we allow fossil fuels to destroy it,” wrote Terry Hughes, a leading coral researcher and the director of the ARC Centre for Excellence, on Twitter in December. “Please, no new subsidized coal mines.”