It calls on the government to appoint an expert panel to conduct a "whole of nation climate and security risk assessment".
Admiral Barrie said the government is "missing in action" and failing its duty to protect the population in Australia - and vulnerable countries in the Asia-Pacific - from climate impacts.
"Our concern is - at the federal government level - they seem to be wasting time. We have had a few reviews. But we don't have a plan. We don't have an action plan for business. We don't have an action plan for states and territories. We don't have an action plan for communities," he said.
"So frankly, we think people have been fiddling around being very complacent and the time for action is now."
He said such impacts include larger scale and more frequent weather events, conflict over resources like water and food, and refugees displaced by rising sea levels.
"I am very worried about our region. I think the Indo-Pacific region is potentially the most dangerous place to be in," he said.
The Intergovernmental Panel on Climate Change report by UN scientists, released last month, identified severe weather events will happen with more frequency and intensity as a result of emissions from human activity.
Extreme heat waves that previously only struck once every 50 years are now expected to happen once per decade because of global warming, while downpours and droughts have also become more frequent, the report said.
Admiral Barrie cited the disappearance of the Himalayan glacier as a fresh water source and the size of the population in the region as factors that could see conflict break out over resources like water and food.
"The potential for conflict is enormous - whether it is squabbling over the rights to fresh water, or about mass migrations with high movements of people from one place to another, when they are starving - you do get violence," he said.
"So I can see a future where, if we can't head all of this off by our inaction now, these are the consequences we might face."
The report says underestimating security risks can prove fatal, "not only for military personnel but for the wider community".
"We saw this during the Black Summer fires that devastated our country," it said.
During the 2019-2020 Black Summer bushfire season, 33 people died - including six Australian firefighters and three American aerial firefighters. Three billion animals were killed or displaced, 3,000 homes were damaged and 24 million hectares of land destroyed.
Source: NASA Earth Observatory
Retired Colonel Neil Greet served in the Australian army in Iraq and Timor-Leste and in peacekeeping and disaster recovery projects, playing a key role in the response from the Defence Force to Victoria’s 2009 Black Saturday disaster.
The fires killed 173 people and destroyed 2,029 homes.
He said there needs to be a shift in thinking from political leaders about the role of the military in mitigating the impact of climate change on communities.
"We've got to change our thinking about national security and what the influences are. Security is a multi-faceted concept. It is not just about shooting bullets, missiles and tanks," he said.
"There is a whole layer of activities that Defence does to support the community, to support people in conflict and move people out of conflict settings.
"Since about 2009, the Defence force has been responding year on year to dramatic events either in our own country or in our near neighbours like Fiji.
"What's really important to understand is the connection between humanitarian activities, civil military activities and how they actually influence security - and how they influence geopolitics. We have got to understand that continuum."
The report said that countries like the US had moved since 2007 to develop intelligence on the security risks from climate change.
It urged the Australian government to set up an "office of climate threat intelligence" to inform governments on how climate change impacts geopolitics in the region.
"The government appeared unprepared for the diplomatic fallout in the Pacific created by Australia’s pro-coal climate policies, and the belated understanding of Chinese initiatives in the region led to some catch-up analysis on climate and security issues amongst near neighbours and in the Pacific," the report said.
The UK will be hosting the UN climate change conference COP26 in Glasgow, Scotland, in November.
Admiral Barrie said the IPCC has underlined the need to plan a rapid decarbonisation of the economy ahead of 2030 to limit global warming to two degrees Celsius.
"If you look at the most recent IPCC report, the world is in serious trouble and the COP26 takes place in Glasgow at the end of next month. And we don't have a plan," he said.
"So, the UK is going (to COP26) with a plan. The United States will have a plan. Europe will have a plan - and all of them are focused on doing something by 2030 that is serious.
"It is not enough for the (Australian) government to stand aside and watch what happens. They have leadership responsibilities and we have to have an action plan."
SBS News has contacted the Prime Minister's Office and the Department of Defence.
Last month, Energy and Emissions Reduction Minister Angus Taylor said Australia remains on track to meet the Paris Agreement target of between 26 and 28 per cent below 2005 levels by 2030.
"Investing in low emissions technologies will enable Australia’s continued success in meeting and beating our emissions reduction targets," he said in a statement on 31 August.
Prime Minister Scott Morrison has previously stated that Australia remains committed to a path of net zero emissions by 2050, but has yet to outline how that will be achieved.
So far, Australia has resisted calls for steeper emissions cuts to match actions by the US, Canada and Japan. US President Joe Biden has pledged to cut carbon emissions by between 50 and 52 per cent below 2005 levels by 2030.
Responding to the release of the IPCC report last month, Prime Minister Scott Morrison said technology would be the focus of emissions reduction efforts - and that he would soon reveal more about actions to take before 2030.
“We will meet and beat our targets,” he told reporters in Canberra at the time.
“We will update what we expect to achieve by 2030, as we always do, and we will make that very clear."