COP30 gets underway in Brazil — and a Trump-shaped hole is hanging over the climate summit

U.N. clime talks get underway successful Brazil connected Monday, with delegations from astir each state acceptable to convene connected the outskirts of the Amazon rainforest to sermon however to tackle the clime crisis.

The medication of U.S. President Donald Trump volition beryllium 1 notable absentee, however. The White House has confirmed it does mean to nonstop immoderate high-level representatives to the summit, marking an unprecedented lack of U.S. officials astatine the conference.

Roughly 50,000 delegates are expected to be the 30th variation of the U.N. clime conference, known arsenic COP30, with talks acceptable to tally done to Nov. 21.

Anna Aberg, probe chap astatine the Environment and Society Centre astatine Chatham House, a London-based deliberation tank, said it was apt a affirmative for the planetary assemblage that the Trump medication won't nonstop immoderate officials to Belem.

"It's, of course, truly unfortunate that the Trump medication has withdrawn the U.S. from the Paris Agreement for a 2nd clip … and that they are pursuing this precise forceful anti-climate docket some successful the U.S., and progressively besides overseas," Aberg told CNBC by telephone.

"In airy of this, I deliberation it is conscionable arsenic good that they're not sending immoderate elder officials to COP to beryllium honorable due to the fact that I don't cognize what they would person been capable to lend fixed the mode Trump is talking astir clime change."

Trump's views connected the clime situation are good known.

The U.S. president has repeatedly described planetary heating arsenic a "hoax" and speaking astatine the U.N. General Assembly successful precocious September, said that clime alteration was the "greatest con occupation ever perpetrated connected the world."

Trump besides urged different countries to displacement distant from renewable energy. "If you don't get distant from the greenish vigor scam, your state is going to fail," Trump said connected Sept. 23.

Chinese President Xi Jinping and Indian Prime Minister Narendra Modi are among immoderate of the different heads of authorities expected to skip the talks, though some countries are acceptable to nonstop delegations successful their place.

The yearly U.N. clime acme is seen arsenic a premier accidental for the planetary assemblage to determination from mounting decarbonization targets to delivering connected them.

Some of the halfway issues acceptable to beryllium discussed see a propulsion to present connected nationalist clime commitments (NDCs), a translation of the planetary fiscal system, ramping up adaptation measures and taking steps to support nature.

The league comes astatine a clip erstwhile the impacts of clime alteration person go increasingly clear — adjacent arsenic the contented has slipped down the contiguous geopolitical agenda.

Speaking to satellite leaders arsenic they hole to convene for COP30, U.N. Secretary General António Guterres called for urgent action to thrust down planetary temperatures and support the 1.5 degrees Celsius people wrong reach.

"Every fraction of a grade means much hunger, displacement, and nonaccomplishment – particularly for those slightest responsible. It could propulsion ecosystems past irreversible tipping points, exposure billions to unlivable conditions, and amplify threats to bid and security," Guterres said connected Thursday successful Belém.

Failure to bounds planetary heating would magnitude to "moral nonaccomplishment and deadly negligence," helium added.

One of the astir important issues astatine involvement astatine COP30, Chatham House's Aberg said, was for the planetary assemblage to present a changeable successful the limb for planetary efforts to tackle the clime crisis.

"We're successful this truly tricky geopolitical environment, not slightest fixed the U.S. withdrawal, and determination are tons of things that this COP needs to achieve," Aberg said.

"But I really deliberation that the astir important happening it tin bash is to nonstop a awesome to the remainder of the satellite that determination are inactive governments and businesses and institutions that privation to instrumentality enactment connected clime alteration and are already taking enactment connected clime change."

Like galore others, Aberg said that portion the U.N. talks volition beryllium "really important" successful shaping the treatment connected however to tackle the clime crisis, the result was highly apt to beryllium underwhelming.

Business leaders called connected policymakers to supply further incentives to assistance accelerate clime action.

Anders Danielsson, CEO of Skanska, for example, said the Swedish operation institution is assured it tin present connected its ain clime targets, portion acknowledging that "we cannot bash it connected our own."

Speaking to CNBC's "Europe Early Edition" connected Thursday, Danielsson said: "We request governmental willingness to thrust this forward."

Tobias Meyer, CEO of logistics elephantine DHL Group, said that helium "strongly" believed a planetary terms connected c would beryllium the champion inducement to assistance curb rising greenhouse state emissions.

"I deliberation we request to get the occupation done," Meyer told CNBC connected Thursday. "We request a terms [on] CO2 emissions that needs to beryllium done globally. That's the champion tool. Strongly judge successful that, and past concern needs to respond to those terms signals and usage the exertion that is disposable to thrust down emissions."

Meanwhile, Henrik Andersen, CEO of Danish upwind turbine steadfast Vestas, urged renewable manufacture leaders to marque definite they proceed to marque themselves heard successful the displacement toward low-carbon technologies.

"It's not lone astir COP," Andersen told CNBC's "Squawk Box Europe" connected Wednesday. "When COP becomes a theoretical workout to cipher what it means to support 1.5 degrees summation [alive] and it's nary longer possible, past astir apt reinvent yourself is my champion advice," helium added.

— CNBC's Emilia Hardie contributed to this report.