Obama faces a fight to protect his climate change agenda after midterm results suggest Senate’s top environmental post will fall to Republican stalwart of climate denial

The Senate’s top environmental job is set to fall to Jim Inhofe, one of the biggest names in US climate denial, but campaigners say Barack Obama will fight to protect his global warming agenda.

Oklahoma Republican Inhofe has been denying the science behind climate change for 20 years – long before it became a cause for the conservative tea party wing. Following midterm elections which saw the Republicans take control of the senate, he is now expected to become the chairman of the senate environment and public works committee.

However, advocates believe Obama will work to protect his signature power plant rules from Republican attacks, and to live up to his earlier commitments to a global deal on fight climate change.

“We think he sees this as a critically important part of his second term legacy and there is no reason why he should not continue to go forward on this… both domestically and around the world,” Gene Karpinski, president of the League of Conservation Voters, told a press briefing.

The campaigners were less clear, however, how far Obama would be willing to fight to block the Keystone XL pipeline project.

Obama will get a chance to show he is still committed to fighting climate change during a trip to Beijing next week, where the US and Chinese are expected to announce new energy co-operation.

Extracting a pledge from China to cut emissions is hugely important now for Obama, who faces growing pressure from Republicans to demonstrate that other countries beyond the US – especially the high-emissions, rising economies – are acting on climate change.

“It is a domestic political imperative for the president to gain emissions reductions from China and other major emitters as much as it is an international policy goal,” said Paul Bledsoe, a climate change official in the Clinton White House.

“The president is under increasing pressure to gain emissions reductions from China and other major emitters in order to justify US domestic mitigation policy. That is going to be the spin Republicans put on it – that we are wasting our time with domestic emissions reductions because they will be swamped by developing countries’ pollution.”

Obama is going to feel that pressure the most from Congress. With his opponents now in control of both houses, the top slot on the Senate’s environment and public works committee passes from a climate defender, the California Democrat, Barbara Boxer, to Inhofe.

He published a book in 2012 calling global warming a hoax, and has compared the Environmental Protection Agency (EPA) to the Gestapo.

A spokeswoman for Inhofe said his first concern was passing the defence budget, and that he would make no comment on his leadership roles until next week.

But if, as expected, Inhofe becomes the new committee chair next January, he will probably try to dismantle the EPA rules cutting greenhouse gas emissions from power plants – the centrepiece of Obama’s environmental agenda.

Industry lobbyists and campaigners said Inhofe lacked the votes to throw out the power plant rules entirely.

Obama would also veto any such move, said Scott Segal, an energy and coal lobbyist with Bracewell & Giuliani.

“I’m not sure we have the votes to advance those across the finish line particularly if they are vetoed,” Segal told a conference call with reporters. Instead, he said he expected “tailored changes”, which could weaken the rules.

Bledsoe did expect, however, that Obama will sign off on the controversial Keystone XL project early next year.

Republicans have said approving the pipeline, built to pump tar sands crude to Texas Gulf Coast refineries, would be an early order of business.

Obama in his post-election press conference gave no indication what he would decide. But Bledsoe said: “I actually believe the president is likely to approve the piepline and in the process deny Republicans a politically potent issue.”

From his perch in the Senate, Inhofe is expected to launch multiple investigations into the EPA – including Republican charges that the agency leaned heavily on a campaign group in drafting the proposed new rules.

But as committee chair, Inhofe is unlikely to indulge in quite the same level of theatrics on climate denial, said RL Miller, a California lawyer and founder of the grassroots organising group, Climate Hawks Vote.

“I expect we are going to see less headline-grabbing efforts on the EPA and more of simply throttling their budget,” Miller said. “If he touches climate denial at all he is going to be ridiculed in public and in the media. If he is smart, he is going to be very quiet publicly, and it will be death by a thousand cuts in the kind of budget battles that people like Jon Stewart don’t pay attention to.”

Despite their upbeat postures, Tuesday’s results were a big setback for campaign groups which had invested an unprecedented amount in trying to elect pro-climate candidates to Congress.

The former hedge fund billionaire, Tom Steyer, spent nearly $75m on advertising and organising in only seven races, making him the biggest known single spender in these elections. Only three of his candidates won.

“There is no way to dance around the issue that in too many races we lost good allies,” Michael Brune, the director of the Sierra Club, told a briefing. “We see those people being replaced by people that are against our values.”

But the environmental leaders blamed the poor showing on low turnout in an off election year – and continued to insist that climate change was becoming a top-tier issue.

They insisted their effort had put climate change on the electoral map – a big shift from 2012 when virtually no candidates would even utter the words climate change.

This time around, Republican candidates were forced to back away from outright climate denial, the campaigners said.

They noted Cory Gardner, the newly elected Republican Senator from Colorado, had appeared in campaign ads with wind turbines, after earlier disparaging climate science. “Climate denial is an endangered species,” Brune said.