Australia’s military will be less ready to confront other security crises if troops are increasingly required to respond to climate-related disasters, a former chief of the Australian defence force has warned.

Retired Admiral Chris Barrie made the comments in an interview with Guardian Australia as he called on the Australian government to pledge at the Glasgow climate conference to cut emissions by more than 50% by 2030, declaring: “We need to all pull together.”

“It is no longer sufficient to say, ‘it doesn’t matter what we do, the defence force will be there to pick up the mess or sweep up the mess afterwards’,” Barrie said.

Barrie, now an executive member of the Australian Security Leaders Climate Group, said Scott Morrison had written to assure it that the government would release a plan before November’s UN summit – but “we haven’t seen enough to be convinced that the government is doing anything serious” about the climate crisis.

The ADF did not recruit people to fight bushfires and sweep up after floods, Barrie said, but was increasingly relied on for such purposes because it was a workforce the government controlled.

“The defence force that we can afford to have will never be big enough to deal with concurrent events and extreme weather events like the black summer bushfires,” said Barrie, who was chief of the ADF from 1998 to 2002.

“And that’s why we need to think carefully about how we are going to head off the likelihood that these things might happen, and then be prepared to deal with them – but not using ADF people. They’re the most expensive people you can buy to do this kind of work.”

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Asked if the climate crisis would leave the ADF less prepared to respond to broader strategic challenges, such as China’s military activities in the region, Barrie replied: “Let’s say we are headed to 3C [of warming] and we’re finding our ADF is out there doing those kinds of work. If there’s a defence emergency and they all bugger off, where are we left?”

The Australian government’s defence strategic update, published last year, warned of rising tensions between China and the US and said high-intensity conflict in the Indo-Pacific was “less remote than in the past”.

The document included only a passing reference to climate change, saying threats to human security “will be compounded by population growth, urbanisation and extreme weather events in which climate change plays a part”.

Barrie said he believed the foreign minister, Marise Payne, and the defence minister, Peter Dutton, were “led by their US counterparts” to include extensive comments about climate change in a joint statement issued after the annual Ausmin talks in Washington DC last month.

The statement also stressed the 2020s as a “critical decade”, recognised “that the impacts of climate change at 1.5?C are much lower than at 2?C”, and acknowledged “the global security threat posed by climate change”. The US Department of Defense will now share its defence-related climate assessment tool with Australia.

Barrie said that development “reinforces the view that the other players around the globe are concerned about Australia’s position and they’re doing their best to try and get Australia to do more before Glasgow”.

While domestic political debate in Australia has largely focused on Morrison’s struggle to win support from the Nationals to firmly commit to net zero emissions by 2050, Barrie noted the need for deeper cuts this decade.

Barrie believes that should include strengthening Australia’s Tony Abbott-era pledge to reduce emissions by 26% to 28% by 2030 compared with 2005 levels.

The Australian Security Leaders Climate Group argues Australia needs to mobilise “all the resources necessary to reach zero emissions as fast as possible”, and Barrie said he believed the 2030 target should be more than 50%.

The comments come after a senior US climate official, Jonathan Pershing, said in August Australia should be considering a 50% cut by 2030, given the urgency of the threat posed by global heating.

Barrie said the Australian government should look at the climate crisis in a similar way as the Covid-19 pandemic.

“What Covid is telling us is that everybody has to pull in the same direction, that it’s not good enough for half the people to be vaccinated and for half of the people not to be vaccinated,” Barrie said.

“It’s not good enough for people to say, ‘it doesn’t actually matter what I do, I’ll do what I damn well like, but everybody else better behave themselves’. Because we are all on the planet together – we’re all on earth together. And on climate change and on dealing with the pandemic, we need to all pull together.”

Morrison signalled to a group of metropolitan Liberals during a private briefing last week that he wanted to reach an agreement before Glasgow on both a policy roadmap and a 2050 net zero target, although some in the Nationals remain opposed.

The Morrison government is facing renewed calls to lift its more immediate climate goals, after New South Wales last week became the third state to set a target of cutting emissions roughly in half by the end of the decade compared with 2005 levels.

Such a target is consistent with what scientists say is necessary for the developed world to live up to the goals of the Paris agreement.