The Cop28 climate summit is set to bring together an eclectic mix of politicians, officials, business leaders, celebrities, faith and community leaders, scientists, journalists and campaigners as the world plots a way forward on tackling climate change.
On the sidelines are big hitters including billionaires and activists who do not directly take part in negotiations but have the clout to move money, influence the debate and have their voices ringing in leaders' ears.
Here are some of the big names set to attend the climate summit in Dubai.
The Vatican has confirmed that Pope Francis will attend Cop28, a first for a sitting pontiff at a UN climate conference. It will be his second papal visit to the UAE after his historic three-day trip in 2019.
The pope will address the summit before holding private bilateral meetings while heads of state and government are in Dubai. He will also open a “faith pavilion” on the Expo City site.
The pope is a head of state himself and the Vatican has a 2050 net-zero goal, but its emissions are negligible on a global scale and his role as a moral voice will carry greater weight.
A regular advocate of climate action, Pope Francis recently published a 7,000-word “apostolic exhortation” setting out his latest political and spiritual take on global warming.
The piece, an update to the 2015 thesis on climate change, said it was “no longer possible” to doubt its human origin despite what he called some “dismissive and scarcely reasonable opinions” even within the Catholic Church.
Pope Francis expressed hope that Cop28 would represent a “change of direction” and usher in a “decisive acceleration of energy transition”, warning a failure to do this would be a “great disappointment and jeopardise whatever good has been achieved thus far”.
Several religious leaders are expected to speak at side events, while Britain’s Archbishop of Canterbury, who attended Cop26 in Glasgow, addressed a recent Abu Dhabi faith summit to say there is “much more to be done” on tackling climate change.
King Charles III
Britain’s King Charles III has been an outspoken advocate of the natural world since before UN climate conferences existed, having been ridiculed after admitting in the 1980s that he liked to talk to his plants.
Buckingham Palace confirmed he will attend Cop28 at the UAE’s invitation. He will deliver an opening address, meet regional leaders and attend a reception to launch a business and philanthropy forum.
Forbidden by constitutional norms from wading into British political debate, the king has to tread a careful line. He is attending at the request of Prime Minister Rishi Sunak’s government, which had said Cop27 was not the “right occasion” for him to appear.
While he cannot negotiate or support specific policies, the soft power of the monarchy carries clout and can be used to win friends, open doors and give Britain a prominent role at the summit’s opening.
In remarks at Cop26 in Glasgow, Prince Charles, at the time, told leaders that “the cost of inaction is far greater than the cost of prevention” as he urged them to find ways of overcoming their differences.
King Charles III at Cop summits – in pictures
The software billionaire and philanthropist has confirmed his attendance at Cop28, calling it an “important opportunity to check on the world’s progress”.
In the build-up to the summit, Mr Gates addressed the Abu Dhabi Climate Tech conference where he backed the UAE to host a summit with “oil and gas at the table”.
Once the world’s richest man, Mr Gates is a prominent backer of clean energy projects as Cop28 looks to fill funding gaps to help developing countries reach their climate objectives.
With a fund called Breakthrough Energy, he says he hopes to tackle the problem in which “the world needs to cut its carbon emissions to net zero, but the poorest countries – who have done little to contribute to climate change – desperately need access to more energy”.
The Bill & Melinda Gates Foundation is also a partner in the business and philanthropy forum to be launched by King Charles.
Other business leaders backing climate action include Jeff Bezos and his Earth Fund and Elon Musk via a $100 million prize for carbon removal technology, although they have not revealed whether they will attend Cop28.
UN big hitters
UN agencies such as the World Health Organisation are not directly involved in negotiations but still have a prominent voice at Cop summits.
WHO chief Dr Tedros Adhanom Ghebreyesus will lobby for health considerations to be embedded in climate policy, while the International Atomic Energy Agency and its head Rafael Grossi are pushing for nuclear power to have a crucial role in the energy transition.
Jim Skea, the newly elected head of the Intergovernmental Panel on Climate Change – the scientists who advise world leaders on what is happening to the planet – is also due to attend Cop28.
Ones to watch
Greta Thunberg and a group of her fellow climate campaigners staged protests during pre-Cop28 talks in Bonn, Germany, during the summer, but the Swedish activist has not confirmed whether she will be in Dubai.
While Ms Thunberg, who refuses to fly because of the carbon footprint, did not attend Cop27 in Egypt, some activists made a road and rail journey through Europe before taking a plane from Istanbul.
One prominent activist, Vanessa Nakate from Uganda, is confirmed as attending Cop28 side events, including a discussion on climate-induced migration from the world’s most vulnerable nations.
The Fridays for Future movement has been split over the Israel-Gaza conflict. Leading figures including Ms Thunberg have made pro-Palestinian comments, while a prominent German activist, Luisa Neubauer, has distanced herself by speaking out against anti-Semitism.
Cop summits often attract celebrities from the world of sport and entertainment who want to be associated with climate action.
Attendees at the past two summits have included Leonardo DiCaprio, Emma Watson, Amir El-Masry, Ellie Goulding and Andy Murray.
Celebrities entering the debate before Cop28 include actress Joanna Lumley, who has urged world leaders to pay attention to wildlife and biodiversity.
Ex-politicians who no longer represent their countries often take the opportunity to have their say at a Cop summit.
Former US president Barack Obama and ex-New York mayor Michael Bloomberg have appeared at recent summits. Al Gore, US vice president from 1993 to 2001, is a regular participant after turning his focus to climate change after leaving office.
Britain’s former prime minister Boris Johnson raised eyebrows by speaking at Cop27 last year, weeks after he was forced from office. The move was interpreted as throwing down the gauntlet to current leader Mr Sunak who was initially reluctant to attend.