Tuvalu climate change minister Maina Talia issued the warning to a delegation of world leaders visiting the small island nation on Tuesday as part of the pre-COP31 event in the Pacific.
Fourteen world leaders from nations including Australia, Solomon Islands, Vanuatu and Mauritius visited Tuvalu for the event despite persistent rain that curtailed some plans.
The event was designed to show leaders the impacts of climate change firsthand in one of the world's lowest-lying nations, where land sits an average of two metres above sea level.
The tour was scheduled a month before the United Nations' Conference of the Parties climate talks in Turkey, where Australia will host negotiations.
But the headline event would need to deliver genuine climate commitments and action, Dr Talia told attendees, including work to phase out fossil fuels and keep 1.5 degrees of warming within reach.
"COP31 cannot be another talk shop or debate over ideas. Our discussions here in Tuvalu and Fiji must deliver strategic action," he said.
"We must transform how COPs have operated for the past 10 years."
COP31 discussions should also include commitments for more grants to endangered island nations, Tuvalu Prime Minister Feleti Teo told leaders, as their communities were suffering an unfair burden.
"Why should countries like Tuvalu take on more debt to protect ourselves from a climate crisis we did so little to cause?" he said
"Climate finance must not push vulnerable countries deeper into debt simply to survive."
Representatives from 30 nations arrived on the nation of nine islands and atolls early on Tuesday for a traditional welcome ceremony, followed by a brief visit to one of the sites being built by the Tuvalu Coastal Adaptation Project.
The multimillion-dollar program is reclaiming coastal land over four sites, with a goal to add more than 20 hectares that are safe for habitation by the end of 2026.
The land would be built six metres above the reef flat to ensure it would resist even the highest tide of 3.2 metres, project manager Alan Resture said, and would be used to accommodate housing, schools and hospitals.
"What we are doing here has shown to the world that adaptation is not a dream," Mr Resture told AAP.
"Our leaders are working tirelessly to make sure the people of Tuvalu remain safe from all the ... adverse impacts of climate change and sea-level rise."
The event was the first official visit to Tuvalu for Prime Minister Anthony Albanese, who said the project showed what actions could be taken to adapt to existing global warming while planning to avoid greater impacts.
"It was a reminder as well that we can't afford to just deal with adaptation, as important as that is," he said.
"We need to deal with the fundamental issue of the rising emissions and the need to keep 1.5 degrees very much on the table."
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