ShellNo flotilla participants float near the Polar Pioneer oil drilling rig during demonstrations against Royal Dutch Shell on May 16, 2015 in Seattle. (David Ryder/Getty Images)

Even as President Obama further amplifies his rhetoric about addressing climate change, a coalition of environmental organizations released a letter Monday seeking to push his administration much further still. Not content with recently announced curbs on emissions from fossil fuel fired power plants, the groups want the president to use his authority to stop new leases for the development of fossil fuels in public lands and waters — a dramatic change in policy that would not only affect major companies but could also decrease future federal revenue collected from these leases.

“Here at home, the longstanding U.S. policy of leasing federal public lands and oceans to corporations for coal, oil and gas extraction must end,” the statement reads. “As the world focuses on climate change in advance of negotiations in Paris this winter, we urge you to demonstrate strong climate leadership by stopping new leasing of our publicly owned fossil fuels.”

According to the U.S. Energy Information Administration, sales of fossil fuels produced on U.S. public land in 2014 included 651 million barrels of crude oil, 3,551 billion cubic feet of natural gas, and 402 million short tons of coal.

The statement is signed by a coalition of green groups, including the Sierra Club, Greenpeace,, Friends of the Earth, Rainforest Action Network, and the Center for Biological Diversity, as well as numerous individuals. Notably, some other leading green groups, such as the Natural Resources Defense Council and the Environmental Defense Fund, are not signatories, suggesting that not all environmental organizations are ready to push the president this far, especially in light of his recent intense focus on climate change, epitomized by the newly finalized Clean Power Plan.

Nonetheless, the statement is significant because it represents the latest stage in the development of a climate grass-roots movement that has already brought us the Keystone XL pipeline battle.

“I think that this is the next frontier of climate advocacy,” said Michael Brune, the executive director of the Sierra Club, which backed the statement. “We know that we have made genuine progress in cutting carbon from cars and trucks and increasingly from the electric sector. And all of that is important, it’s necessary — and it won’t get the job done unless we begin to curtail development of fossil fuels, particularly in sensitive areas.”

The letter highlights that even as the Obama administration has focused on reducing warming-causing emissions through traditional regulatory means — most centrally, the EPA’s newly released Clean Power Plan — many environmental activists have pushed a still bolder strategy, and one that far more directly clashes with industry. They have been seeking to block fossil fuel projects or infrastructure, such as the Keystone XL pipeline, as well as calling for universities and other major institutions to divest from holding stock in major companies operating in that industry.

That’s the common theme that ties together the growing divestment movement, objection to the Keystone XL pipeline, protests against Shell’s plans to drill for oil in the Arctic, and now, the letter focused on federal fossil fuel leasing.

[Powder River coal leasing prompts IG, GAO reviews]

Hints of the theme were also apparent when, during President Obama’s recent Alaska trip to highlight climate change, many environmentalists faulted the president for the administration’s approval of Shell’s drilling plans in the Arctic. “His recent trip to Alaska, he didn’t even mention Arctic drilling,” said Ruth Breech, a campaigner with the Rainforest Action Network who helped organize the new statement. “This omission is just amazing. He’s up there talking about the climate crisis but he’s not talking about how he just approved and opened up a new carbon reserve.”

But in fact, the rift is of long standing — for a number of years, many environmental groups have simultaneously praised the president’s climate steps but also faulted his continual reliance on an “all of the above” energy strategy that supports the development of U.S. fossil fuel resources as well as renewables.

The groups claim that the president could, “with a stroke of a pen,” prevent as much as 450 billion tons of “potential” greenhouse gas emissions from the leasing of public land for fossil fuel development. The source of the figure is a recent report prepared for Friends of the Earth and the Center for Biological Diversity, which found that coal was the largest source of potential emissions, followed by oil shale.

“Whether it’s with Keystone XL, or an expansion of drilling in the Arctic, or leasing on public lands, we need to see some examples of the fact that the president understands that energy supply and demand are linked, and we have to start to develop a supply side strategy to address climate change,” said Brune.

[Hillary Clinton breaks with Obama to oppose Arctic drilling]

As a broader justification for this “supply side strategy,” green groups often cite research suggesting that a large proportion of current fossil fuel reserves would have to remain unburned if the world is to have a serious chance of keeping warming below 2 degrees Celsius above pre-industrial levels, a widely agreed upon international target.

Indeed, a study published last week found that if humans burn all available fossil fuel reserves, the emissions would be sufficient to entirely melt the gigantic ice covered continent of Antarctica, triggering over 100 feet of sea level rise.

How the Obama administration will respond to the increasingly loud “supply side” demands from environmental activists remains to be seen — but the push may also influence Democratic presidential candidates. Hillary Clinton, in a contrast with Obama, recently came out in opposition to Arctic drilling.

The Sierra Club’s Brune thinks the “supply side” approach is still only beginning to build momentum. “Give it time,” he said. “I guarantee our conversation in a year is going to be different than it is now.”