So far, Donald Trump has said very little about climate change and energy policy beyond his Twitter posts on the issues.

He has called global warming a “hoax,” for example, and claimed that the Chinese fabricated climate change (just a joke, he later said). And in an interview this week with Reuters, he said that he was “not a big fan” of the Paris climate accord, and that “at a minimum I will be renegotiating those agreements.”

But more clues about Trump’s views on environmental issues emerged this week from a four-page briefing on energy policy prepared for the presumptive Republican nominee by Rep. Kevin Cramer, R-N.D., an early supporter of Trump.

Cramer, who defines himself as a climate change skeptic, discussed in his briefing paper a variety of government regulations that Trump might do away with if he were president.

They included the Obama administration’s Clean Power Plan, currently pending in the courts, as well as a federal rule intended to protect waterways and wetlands, and a regulation setting standards for methane emissions that the Environmental Protection Agency completed last week.

In an interview, Cramer said he wrote in the briefing paper that a growing number of Americans wanted action to reduce carbon dioxide emissions from fossil fuels. And he outlined a broad energy policy that embraced all types of fuel sources — including coal, oil, solar, wind and hydropower — that he called an “all-of-the-above, America-first energy message.” Cramer, from a heavy coal- and oil-producing state, said it was important that any policy does not “punish coal” or other fossil fuels.

Trump may soon share more of views. His press secretary, Hope Hicks, said that the campaign “will have more to say on the topic soon.” He is scheduled to speak at an oil conference in North Dakota on Thursday.

Whenever Trump does fill in more details on the topic, he will have eager audiences both inside and outside his political party.

Republican leaders worry that Trump’s views, his climate-denying Twitter messages notwithstanding, could end up somewhere left of the party’s mainstream.

“I think there is concern about where he stands because he hasn’t come out strongly one way or another,” said a Republican aide who insisted on anonymity because she was not authorized to speak publicly about the matter.

Environmental groups, for their part, have seized on each new scrap of information to warn of disastrous consequences should Trump be elected.

“Trump and Cramer are two peas in the climate denial pod, who would make reckless attacks on the progress we have made in the fight against climate change,” Seth Stein, a spokesman for the League of Conservation Voters, said in response to news reports Thursday afternoon about Cramer’s briefing paper.

If Trump were to acknowledge the reality of climate change, that might provide some Republican politicians with political cover to do so as well.

Since 2010, when a Republican member of Congress, Bob Inglis, lost his re-election bid after saying he would favor a carbon tax, many in the party have regarded any mention of climate change as the equivalent of political suicide. (Inglis has since focused on persuading conservatives to be “less averse” to addressing climate change, and started a nonprofit group, the Enterprise and Energy Initiative, focusing on conservative responses to the problem.)

Yet polls have repeatedly found that a majority of Republican voters, particularly young ones, believe that climate change is real and that the government should take action to reduce carbon dioxide emissions.

Anthony Leiserowitz, director of the Yale program on Climate Change Communication, said that a nationally representative survey of 1,004 registered voters, conducted in March in conjunction with George Mason University, found that 56 percent of Trump voters agreed that climate change was occurring. Just over half of them, however, thought those changes were caused by natural changes in the environment, rather than the result of human-generated emissions.

The number of Americans overall who say climate change is real has risen to 73 percent from 66 percent two years ago, according to the Yale/George Mason poll. But the jump among those who believe in global warming was steepest among Republicans, with a 16 percent increase in two years among all Republicans, and a 19 percent increase among conservative Republicans.

Jay Faison, a North Carolina businessman who describes himself as a conservative Republican, said that denying climate change was “the No. 1 peel-away issue” that could pull voters away from supporting a candidate, according to research conducted by ClearPath, the organization he founded to promote clean energy and climate change policies that could appeal to conservatives.

Faison, who has said he will devote $10 million to persuading Republican candidates to address climate change, said that a platform that emphasized clean energy solutions could make a difference of 1 or even 2 percent in close elections — “which decides a whole lot of elections.”

Like others on both sides of the political aisle, Faison said he had no idea what Trump’s views on climate change might be. But he noted that the candidate had once said in an interview that he believed in “immaculate air.”

“If you believe in air pollution, then perhaps we could get to the same place,” Faison said. “If we have cleaner energy solutions and it brings more energy independence, more jobs, and lower air pollution, then we would do these things even if we don’t agree with scientists on climate change.”

It is a view that echoes those expressed by Cramer, who in the past has said he would support a small carbon tax if the revenue went to research on clean fuel technologies.

“There is no downside in reducing emissions from fuel,” said Cramer, who added that “the climate is clearly changing,” but that he was skeptical about how much humans were contributing to the change, and about the regulatory solutions offered by Democrats.

Climate change has long been far down on the list of issues that voters say are important to them. (Developing clean energy was ranked No. 21 of 23 issues by Trump supporters in the Yale/George Mason survey).

But Jerry Taylor, the president of the Niskanen Center in Washington, a libertarian think tank, said that the importance of issues in voters’ minds may change during an electoral campaign if a candidate talks about them repeatedly.

Taylor said that if Trump continued to deny the existence of climate change, Hillary Clinton could use that to claim that Republicans were anti-science and out of touch with reality.

“Climate contributes significantly to the poor branding of the Republican Party,” he said, adding that just because an issue was a low priority to voters “doesn’t mean it can’t be used to devastating effect against you.”

© 2016 The New York Times Company