Climate action is set to dominate discussion at the Commonwealth Heads of Government Meeting, which the King and Queen will preside over for the first time.

It comes as a report published by the United Nations on Friday warns that without action the world could warm by up to a massive 3.1 degrees this century.

The biennial meeting is being hosted in Samoa, the first time it has been held in the Pacific region. Experts and leaders say it is pertinent timing to put a spotlight on climate impacts in the region.

The effects of climate change pose an existential threat to smaller island nations.

On Friday, an opening ceremony will precede the official group photo and the King will then hold a reception for newly appointed heads of state before a broader reception for leaders and their partners.

There will be a more secretive leaders’ retreat at a beach resort on Saturday.

Pacific affairs expert George Carter said the meeting’s Pacific venue meant leaders had the chance to see first-hand the impact of climate change.

Heavy rains and localised flooding across the Samoan capital Apia on Thursday was a timely reminder of what vulnerable nations were going through, he said.

“In terms of sea level rises, this has been an issue Pacific islands have focused on this year,” he said, referencing previous meetings at the Pacific Islands Forum and UN General Assembly where the issue was brought up.

“What’s unique is the lived experience and the reality of changing weather patterns here in the Pacific.”

Pacific expert Dr Meg Keen agreed island nations were pushing for concrete action on climate change, including greater access to finance to tackle associated challenges, such as the need to build sea walls to stop the rising tide.

Prime Minister Anthony Albanese has flagged Australia taking a leading role in dealing with climate change after criticism from Tuvalu’s prime minister that larger Commonwealth nations needed to do more to phase out fossil fuels.

Foreign Minister Penny Wong, who is also at CHOGM, said she hoped leaders would be able to agree to a forward-leaning statement on climate action and outline steps to respond to the threats it poses.

Pacific island nations retaining sovereignty over exclusive economic zones – which grants rights over ocean resources across a specified area – as sea levels rise and threaten legal rights should also be addressed, she said.

Albanese will also hold his first face-to-face meeting with British Prime Minister Keir Starmer since the latter took office.

King becomes Samoan ‘high chief’

The King has been made ‘Tui Taumeasina’, which means high chief, on his visit to the village of Moata’a,

He was presented with a half-coconut filled with the kava brew, which is slightly intoxicating and peppery, while the drink – which is known as “ava” locally – holds a special place in Pacific culture.

When the drink was ready, a Samoan man screamed as he decanted it, and then gave it to the King, who said “May God bless this ava” before taking a sip.

The King also toured a mangrove reserve to learn about the climate change impact on Pacific island nations, which are frequently battered by mega cyclones.

He has spent a lifetime raising awareness about environmental issues and has characterised global warming as the greatest threat to humanity.

The high chief title for the monarch comes days after Indigenous crossbench Senator Lidia Thorpe accused him of “genocide” during a protest at parliament in Canberra.

The King – who spent six days in Australia on his first overseas tour as monarch – is said to be in “good spirits”.

Royal biographer Robert Hardman told People magazine that he appreciated having the support of the Queen, 77, on the royal tour.

“She keeps his spirits up and is a reassurance, but she also steps in here and there,” Hardman said.

“We know she is not particularly keen on long-haul travel and yet has thrown herself into this trip.”

UK faces pressure on slave reparation

Britain’s leaders will likely face uncomfortable questions about reparations for the trans-Atlantic slave trade at Pacific talks in Samoa, after Caribbean leaders said they would thrust the matter into the spotlight.

Starmer has said that compensation for slavery isn’t on the agenda.

But the issue threatens to boil over anyway, presaging an uneasy summit for him and King.

The Commonwealth group of 56 nations has “taken on issues other people have always run away from” before, the organisation’s Secretary-General Patricia Scotland told The Associated Press on Thursday when asked if financial reparations would feature in talks.

She didn’t confirm BBC reports that a draft text of the statement to be issued by leaders after meetings on Friday and Saturday includes an acknowledgement of calls for “reparatory justice” over the slave trade.

The text of the statement could change before its release, and British officials reportedly vetoed a plan for a separate declaration on reparations, the BBC said.

Caribbean and African leaders have led the push to address the reparations issue.

The summit should involve “a ‘come to Jesus’ moment where we truly look at one another in the eye and say, ‘look, this is what happened’,” Bahamas Prime Minister Philip Davis told Politico on Thursday.

-with AAP