Tuvalu has warned Australia needs to take "true leadership" and match words with action as it assumes a leadership role in global climate negotiations.
Australia's three-year push to host the COP31 climate summit in 2026 was sunk this week, as it instead compromised with bidding rival Turkey.
As part of the deal, the next UN climate conference will be staged in Antalya, rather than Adelaide, with Climate Minister Chris Bowen taking on a key role.
The outcome has disappointed the Pacific, which was promised a hosting role in partnership with Australia, with Pacific Islands Forum nations all backing the bid.
There were hopes a successful bid might have bridged the gap between Australia and the Pacific on climate ambitions, given Australia's status as one of the world's top three exporters of fossil fuels.
Tuvalu Climate Minister Maina Talia said he was "heartbroken" by Australia's support of fossil fuel expansion.
"This clear disregard for the concerns we raise year in and year out betrays the trust of the people of Tuvalu, the Pacific and indeed, Australia," he said.
"Our fates are indeed intertwined.
"That is why we ask Australia - as our tuakoi - to choose a path of true leadership, one that matches words with action, and ensures a future where all our peoples can thrive."
Mr Talia acknowledged Australia's efforts to increase renewable energy production, but savaged the extension of coal mines and plans to produce gas through to 2070 as "incompatible with a viable future for Tuvalu".
"Australian leaders nowadays, more often than not, say the right things. But there is a disheartening disconnect between their words and their deeds," he said.
"Australian leaders recognise the Pacific's truth, but fail to live by it."
Mr Talia made the comments in the launch of a new report for the Fossil Free Pacific Campaign Coalition detailing three decades of departure between Australia and the region on climate policy.
Other advocates in Belem, the Brazilian city at the gateway to the Amazon, were focusing on the hard grind of emissions reductions.
Tuvalu joined with Vanuatu and Australia's Smart Energy Council to unveil a plan to decarbonise the Pacific, which Mr Bowen helped launch.
Australia is the leading contributor to climate finance and aid to the region, helping countries reduce their own footprint and adapt to the impacts of climate change.
The Australian Conservation Foundation has also launched a report calling into question Australia's forestation rates, which in turn could overstate the amount of carbon stored by forests.
"The clearing of mature forests and woodlands to expand cattle pasture is a major driver of Australia's extinction record and a serious source of climate harm," ACF spokesman Nathaniel Pelle said.
"It is a fantasy to claim that is balanced out by new saplings or the thickening of existing vegetation that has sprung up because of a few wet La Nina years."
