Justin Solet planted his foot on the edge of his camouflage green boat in Bayou Chauvin and pointed to a natural gas rig protruding from the waters ahead. A web of pipelines and rusted storage tanks jutted up from the marsh behind him as a shrimp boat floated past and markers for crab traps bobbed on the water’s surface.

“We are water people,” said Mr. Solet, 37, a member of the United Houma Nation, a Native community with many shrimpers, oyster farmers and crab fishers who depend on the Gulf of Mexico’s bounty. “This is their livelihood. And it’s right next to these tanks that I don’t think have been fixed or serviced in years.”

Oil and gas wells and drilling equipment are a persistent threat to the fishing industry in the Gulf. In addition to the 2010 Deepwater Horizon disaster, there have been dozens of less-noticed oil spills. Last month, on the first day of Louisiana’s inshore shrimp season, a tank platform collapsed, pouring 14,000 gallons into Terrebonne Bay and ruining the catch.

Under a new climate and tax law, the federal government will lease hundreds of millions more acres for offshore drilling in the Gulf in the next decade, even as it invests $370 billion to move the country away from fossil fuels and develop wind, solar and other renewable energy.

More Gulf leasing was among the concessions that Democrats and President Biden made to Senator Joe Manchin III of West Virginia, a Democrat who champions fossil fuels and whose vote for the legislation was crucial in the evenly divided Senate.

It came despite Mr. Biden’s promise as a candidate to end new drilling on public land and in federal waters “period, period, period.” And it came even though Deb Haaland, who will oversee the leasing as the interior secretary, said as a congresswoman in 2020 that “we need to act fast to counteract climate change and keep fossil fuels in the ground.”

The leasing also follows a warning from the International Energy Agency that nations must stop approving new fossil fuel projects if the world has any hope of keeping the average global temperature from increasing 1.5 degrees Celsius above preindustrial levels. That’s the threshold beyond which scientists say the likelihood of catastrophic climate impacts increases considerably. The planet has already warmed 1.1 degrees Celsius.

The new law condemns communities like Houma, which are already dealing with storms made more intense by climate change, to continued reliance on oil and gas drilling, even as other parts of the United States race toward renewable power, said Cynthia Sarthou, executive director of Healthy Gulf, an environmental organization based in New Orleans.

“We were really sold down the river and had to serve the role of bargaining chip without the input of folks in Louisiana,” said Jack Sweeney, an activist with the Louisiana Bucket Brigade, an environmental nonprofit organization. The group’s members traveled to Mr. Biden’s home state of Delaware last month to point out that, while Congress and the administration are enabling more drilling in the Gulf, they are protecting the Atlantic and Pacific coasts. “The treatment of coastal Louisiana is so different,” he said.

Erik Milito, president of the National Ocean Industries Association, which represents offshore energy companies, said the new law created an “even playing field” for offshore oil and gas alongside wind. His organization said oil and gas production in the Gulf was projected to average about 2.6 million barrels of oil equivalent per day through 2040, and said the industry would support an estimated 372,000 jobs in the region during that time.

As oil drilling technology improves, the physical footprint of the industry is shrinking, Mr. Milito said.

On Wednesday the Interior Department announced that in compliance with the new law, it has reinstated 307 bids that the agency received last year to lease 80 million acres in the Gulf of Mexico. (The sale was canceled in January by a federal judge who ruled that the Biden administration had not sufficiently taken climate change into account, but it has been revived under the new climate law.)

Analysts have said the lease sale could produce up to 1.1 billion barrels of oil and would most likely emit 723 million metric tons of carbon dioxide into the atmosphere over its lifetime.