The letter is signed by 70 former diplomats – everyone from ambassadors and high commissioners to humanitarian aid co-ordinators and middle-level Department of Foreign Affairs and Trade officials – and expresses the group’s concern for the country’s future environment and economy.

“We are concerned that the climate is changing rapidly and without urgent action … the future of life on this planet looks bleak for our children and grandchildren,” former consul-general for eastern Indonesia and deputy ambassador to Greece Richard Mathews said.

The group says key allies across the globe – including the US – are increasingly voicing concerns that Australia is not “pulling its weight” on climate action.

“Australia’s inertia on commitments undermines our credibility as a regional partner; it undermines our reliability in the minds of our strategic allies; and it will cost us dearly as trading partners,” the letter reads.

“As former diplomats, we see what is happening around the globe, and it concerns us that Australia is not at the leading edge of international action on climate change.”

The country needs to commit to achieving net zero emissions by 2050, they say, and set more ambitious goals to be reached by 2030 too, both before the UN Climate Change Conference in Glasgow in November.

Prime Minister Scott Morrison has spent the past week in the US meeting with President Joe Biden and UK Prime Minister Boris Johnson, who are both locked into the 2050 target, as well as fellow members of the so-called Quad that includes India and Japan.

In an interview with the Seven Network from Washington, Morrison said he was patiently working with his coalition partners, the Nationals, on a deal to reach net zero emissions.

“I’m keen to ensure I bring people together on this so Australians can have confidence we are dealing with climate change, that we care deeply about their concerns about what the change means for them,” he said.