The Trump administration has confirmed that no high-level representatives will be sent by the US to upcoming UN climate talks in Brazil, underscoring the administration’s hostile stance towards action on the climate crisis.

The US has always sent delegations of various sizes to UN climate summits over the past three decades, even during periods under George W Bush and Donald Trump’s first term where there was scant desire to address the global heating crisis.

But the upcoming talks in Belém, Brazil, next month are set to be devoid of an official American presence to an extent never seen before. Trump has previously called the climate crisis a “hoax” and a “con job” and has said that the US will withdraw from the Paris climate agreement, which calls for countries to limit the dangerous global temperature rise.

“The Green New Scam would have killed America if President Trump had not been elected to implement his commonsense energy agenda – which is focused on utilizing the liquid gold under our feet to strengthen our grid stability and drive down costs for American families and businesses,” Taylor Rogers, a White House spokeswoman, said in a statement to the Guardian. The “scam” reference relates to the climate policies of Joe Biden.

“President Trump will not jeopardize our country’s economic and national security to pursue vague climate goals that are killing other countries,” she added.

Earlier this year, the US state department shuttered the office that typically deals with climate issues. The position of climate envoy, which operated under Biden, has also been scrapped.

In jettisoning multilateral talks with other countries, the White House has favored an approach whereby Trump strikes deals directly with individual countries.

In recent months, the US president has secured agreements from the European Union, to purchase $750bn in American oil and gas, as well as countries such as Japan and South Korea to develop rare earth materials, nuclear power and fossil fuel projects.

Trump has also urged other countries to shift away from renewable energy. “If you don’t get away from this green scam, your country is going to fail,” the president told leaders at a UN speech last month. “You need strong borders and traditional energy sources if you are going to be great again.”

The lack of US presence at the Belém talks is a further complication to a summit that already appears troubled.

Countries are meant to submit updated plans to slash planet-heating emissions at the gathering but the vast majority have yet to do so, while many delegates are struggling to secure accommodation in time to attend the talks in the city, which acts as a gateway to the Amazon river.

“The president has made it clear he wants to withdraw from the Paris agreement so it doesn’t surprise me they aren’t sending anyone because they aren’t engaged in this,” said Todd Stern, a former lead climate negotiator for the US during Barack Obama’s presidency.

“I don’t think they would add anything useful. This is a much more aggressive administration now, across the board. I think the great majority of countries aren’t going to pay attention to that, they know climate change is real, you just have to look out of the window to see it is getting worse.”

An assortment of US governors, members of Congress, mayors and activists will be attending the Cop30 summit, with the message that subnational American jurisdictions are still pressing ahead with climate action.

But they have been given no support from the US government in doing so. Sheldon Whitehouse, a Democratic senator from Rhode Island, said on Thursday that he had been told “they weren’t even going to send embassy support for the US delegation, which is a fairly standard courtesy for those of us that did go”.

“So at this point, I don’t think there’s any sign of [the administration attending], but who knows? This is a very mercurial administration. They can decide at the last minute to send a plane to Belém full of climate deniers and fossil fuel operatives.”

One former senior state department official, speaking anonymously, said that it was preferable that the US not attend the talks so that other countries can strike a stronger climate agreement.

“If the choice is no US or a US that is there as a spoiler, to wreck and disrupt things, then I think most countries would prefer there to be no US,” the former official said.