The Obama administration says it's working to boost renewable energy and head off the threat of climate change, but it's not ready to pull the plug on fossil fuels.

The White House this week denied a petition calling for it to halt all new oil, coal, and natural gas leasing on public lands and seabeds, disappointing activists who had urged the Obama administration to stop selling the rights to dig and drill for those fuels. In spiking that plea, the administration touted the rapid progress of renewable energy on its watch and efforts to rein in US emissions of carbon dioxide and other planet-warming gases.

"But even as we move full steam ahead towards cleaner energy, the United States will still need to use fossil fuels in the near term," it added. "So, the administration is working to ensure that energy development meets higher standards for safety and environmental protection."

Many of those involved with the "Keep It in the Ground" movement say their disappointment isn't likely to slow down their campaign, which has grown rapidly on multiple fronts.

"My sense is the White House is aware of the growing power and influence of the Keep It in the Ground movement, and that's why we saw the petition response this week," said Kelly Mitchell, a director at the environmental group Greenpeace.

'No one's proposing that we stop using fossil fuels overnight.'

Just this spring, climate activists hoping to halt the extraction of fossil fuels have been protesting federal energy lease sales around the country, disrupting events in New Orleans and Denver. A protest in Washington drew more than 1,000 people on Sunday. And demonstrators blockaded the rail lines that lead to a pair of oil refineries outside Seattle over the weekend, resulting in more than 50 arrests, according to organizers.

"Our movement is going to continue to grow," said Taylor McKinnon, a campaigner at the Center for Biological Diversity. "The protests are going to continue to grow. The number of people who are involved is going to continue to expand."

McKinnon called the White House response to the online pleading "patently dishonest," saying existing leases can already meet US fossil fuel demand for decades.

"No one's proposing that we stop using fossil fuels overnight," he said. "What we're proposing is we need a rapid transition to clean, renewable energy. We have plenty of fossil fuels already under lease."

The Center for Biological Diversity (CBD) is part of a separate petition submitted as part of coalition of nearly four dozen other groups. A 2015 report by the center argued that Obama could lock away a store of carbon comparable to the entire globe's output in the past decade, simply by saying "No."

Most of that would have to remain off-limits anyway, if the world hopes to reach its goal of limiting climate change to 2 degrees Celsius (3.6 Fahrenheit) over pre-industrial temperatures by 2100. Researchers estimate more than 80 percent of the world's coal reserves, half its natural gas, and about a third of its oil need to be left untouched in order to achieve that mark.

The Obama administration has identified climate change as a top priority from the beginning. It's signed the Paris climate accord, in which nearly 200 countries have pledge to restrain carbon emissions enough to limit climate change to 2 degrees Celsius (3.6 Fahrenheit) by the end of the century. And President Barack Obama used his State of the Union speech to mock the holdouts who insist climate change is a hoax.

It's issued new regulations aimed at reducing carbon dioxide emissions from power plants and reduce methane emissions from the oil and gas industry. It's halted new coal leases on federal lands while it reviews how those leases are issued. And it's cut off the Atlantic seaboard to oil drilling and restricted new exploration in the Arctic to the point where companies are giving up their prospects.

All that has been good, said Mitchell, who called the coal moratorium in particular "phenomenal." But the administration is hamstrung by a gridlocked and largely hostile Congress, and canceling new leases is Obama's best chance to reduce emissions.

"I don't think his lack of a perfect response on this question negates a lot of the progress he's made on things like renewable energy," Mitchell said. "But it's certainly not what the crisis of climate change is requiring."

At the very least, Obama should have temporarily halted all new leases to estimate how much emissions the fuels currently available represent, McKinnon said. The CBD has estimated that even those would blow past what the United States can burn without breaking its Paris commitments.

"There continues to be this very disconcerting disconnect between the administration's climate goals and its federal fossil fuel leasing programs," he said.