This week’s Pacific Islands Forum comes at an important time in the overall trajectory of Prime Minister Scott Morrison’s very personal commitment to an Australian “stepping up” in the Pacific.

To paraphrase the PM, you have to show up to step up. And after skipping last year’s Pacific Islands Forum, Morrison has certainly been doing a fair amount of showing up around the region, with visits to Vanuatu and Fiji at the beginning of the year and the Solomon Islands immediately after his election victory.

Add to this his recent hosting of the new PNG prime minister, James Marape, and it is clear there has been significant energy devoted to establishing personal relationships with some of the leaders he will sit down with this week.

An ‘existential threat’ to the region

Regional politics and diplomacy in the Pacific are not for the faint of heart. It’s clear from the tone of recent statements by Foreign Minister Marise Payne and the minister for international development and the Pacific, Alex Hawke, that there is some disquiet ahead of the Tuvalu get-together.

And with good reason. For some time, the leaders of the region have been becoming increasingly vocal about the lack of meaningful action from Canberra when it comes to climate change mitigation.

Read more: Yes, Morrison 'showed up' in the Pacific, but what did he actually achieve?

Most recently, ten of the Pacifc Islands Development Forum (PIDF) members signed the Nadi Bay Declaration, which advocated a complete move away from coal production and specifically criticised using “Kyoto carryover credits” as a means of achieving Paris targets on reducing emissions.

While this body does not have the regional clout of the Pacific Islands Forum, its membership includes key players, notably Fiji, Tuvalu, and the Republic of the Marshall Islands, whose leaders have all spoken out strongly on the need for stronger action on climate change.

In a speech last month, Fijian Prime Minister Frank Bainimarama urged his fellow Pacific leaders to withstand any attempts to water down commitments on climate challenge in the region and globally.

Bainimarama is attending this year’s Pacific Islands Forum for the first time since 2007, and has already made his presence felt. Earlier this week, he urged Australia to transition as quickly as possible from coal to renewable energy sources, because the Pacific faces

an existential threat that you don’t face and challenges we expect your governments and people to more fully appreciate.

Losing credibility on its ‘step up’

Given the state of Australia’s domestic politics when it comes to making climate change action more of a priority, it is hard to see how Morrison can deliver what the “Pacific family” is asking for.

The recent announcement of A$500 million to help Pacific nations invest in renewable energy and fund climate resilience programs is sure to be welcomed by Pacific leaders. As is the pledge for A$16m to help tackle marine plastic pollution.

But none of this money is new money – it’s being redirected from the aid budget. And it does not answer the call of Pacific leaders for Australia to do better when it comes to cutting emissions.

Mick Tsikas/AAP

Why does this matter? Because it’s becoming increasingly obvious that the inability – or refusal – to be part of the team when it comes to climate change is undermining Australia’s entire “Pacific step-up”.

If Morrison, and the Australian leadership more broadly, want to reassure Pacific leaders that Australia’s increased attention on the region is not just all about trying to counter Chinese influence, this is where the rubber hits the road.

This is not about whether China is doing better when it comes to climate change mitigation than Australia. The Pacific has greater expectations of Australia, not least because Australian leaders have been at pains to tell the region, and the world, that this is where they live - that Pacific islanders are their “family”.

And for Pacific islanders, if you are family, then there are obligations. This week, as has been the case previously, Pacific leaders will make clear that addressing climate change is their top priority, not geopolitical anxieties over China’s increasing role in the region.

Read more: Everything but China is on the table during PNG prime minister's visit

There is little doubt that Australia’s “Pacific step-up” is driven by concerns about the rising influence of China. But Morrison knows better than to voice concerns of that type – at least in public – while in Tuvalu.

Numerous Pacific leaders have made it clear that as far as they are concerned, partnerships with Beijing (for those that have them) provide for greater opportunity and choice.

While they welcome renewed ties with traditional partners like Australia and New Zealand, they maintain a “friends to all and enemies to none” approach to foreign policy. That is unlikely to change any time soon.

Mick Tsikas/AAP

Will Tuvalu prove a turning point?

Tuvalu Prime Minister Enele Sopoaga may well be hoping that when Morrison sees for himself how climate change is affecting his country, he will be so moved personally, he will shift Australia’s stance politically.

Indeed, on arrival in the capital of Funafuti this week, leaders are being met by children sitting in pools of seawater singing a specially written song “Save Tuvalu, Save the World”.

So what can Morrison realistically be expected to achieve during the summit? He will be able to demonstrate Australia’s commitment to other issues that are important to regional security, such as transnational and organised crime and illegal fishing.

He can also hope the personal relationships he has cultivated with Pacific leaders deliver returns by way of compromise around the wording of the final communique, if only to avoid a diplomatic stoush.

But if there is no real commitment to cutting greenhouse gas emissions, he will leave plenty of frustration behind when he returns to Australia.