The Bramble Cay melomys was not, frankly, a particularly prepossessing creature, as one might gather from the little native rodent’s other name, the mosaic-tailed rat.

In life, it had none of the iconic appeal of those more charismatic species that bring popular support to environmental causes. Only by the manner of its extinction is the melomys distinguished: science believes it to be the first mammal species whose demise can be attributed directly to climate change.

The melomys was previously the only mammal endemic to the Great Barrier Reef. Its entire population was confined to the single Torres Strait island for which it was named, a cay inhabited by no people or introduced predators, about four hectares in area and less than three metres above sea level at its highest point.

The last of the melomys are thought to have died somewhere between 2007 and 2009, although it was not until 2014 that the Queensland government released a report conceding that despite a determined effort by scientists, using traps, cameras and old-fashioned foot searches, there were none left.

That report confirmed sea level rise, coupled with increasingly frequent and intense storms and higher storm surges, as the probable cause. The species was washed away while no one was looking.

The announcement caused a brief flurry of interest in the media and prompted a comment piece in the prestigious journal Nature, suggesting the fate of the melomys should serve as a call to heed the science and act urgently to implement policies that mitigate the threat of climate change.

The melomys is the only extinction we know of so far, but things are grim for many other living things.

About 600 kilometres south of Bramble Cay is the Wet Tropics World Heritage Area. Extending in a 450-kilometre-long rugged ribbon from just south of Cooktown to just north of Townsville, the 890,000-hectare heritage area is Australia’s most biologically diverse terrestrial environment.

The way things are going, says Stephen Williams, professor of ecology and climate change at James Cook University, about half the endemic vertebrate species of the wet tropics could be extinct by the end of this century. Most of the rest would be expected to be critically endangered.

“We are a mega-diverse country, meaning we have a lot of wildlife that occurs nowhere else on Earth. Endemic species with limited dispersal options and small ranges are particularly vulnerable to extinction from climate impacts.”

“We have a World Heritage Area rapidly losing the things that made it a World Heritage Area,” he says.

“The reason the Wet Tropics is so special is that it’s a relict of what once existed right across the country, before Australia warmed and dried over the past few million years.

“Overall, we have about 700 species of vertebrates. Of those, about 300 are rainforest species, and about a third of those are found nowhere else in the world. The WHA was created because of those endemic species. But in the past 15 years, about 50 per cent of them are showing significant declines in total population.”

In a sense, the mountains of the Wet Tropics are islands – islands of cooler, wetter climate, surrounded by a rising tide of heat as the climate warms. While the many endemic animals are thought of as tropical species, Williams says, “they can actually only live up in the mountains, in that cooler, wet environment”.

And as the climate heats up – the Wet Tropics have warmed about 1 degree Celsius over the past 100 years, with about half of that happening in the past 15 years – those creatures are being forced ever higher up these mountains.

“We used to see lemuroid ringtail possums down at about 600 metres elevation until about a decade ago,” he says. “About five years ago, they had also disappeared at 700 metres. Now there are indications they are declining at 800 metres.”

The pattern is similar across other species that Williams and his colleagues have monitored over that time. They are being pushed about 100 metres uphill every five years.

“The scary bit is, I look at the data ... and see all of the things we care about retracting up the mountain, on the basis of about half a degree warming in the last 15 years. What’s four degrees going to do? Because the fact is, we’re tracking for about four degrees this century.”

Most of the mountains in the Wet Tropics are under 1200 metres above sea level. Two go up to 1600 metres. In a few decades, these species will reach the top of the mountain and have nowhere else to go.

That is, if they last that long.

On top of the problem of increasing average temperatures is that of extreme heat events, which climate scientists tell us also are becoming more frequent and intense.

Williams cites an example, from 2007, relating to the ringtail lemuroids, which are acutely vulnerable to even moderate heat. They will die if the temperature goes above about 29 degrees for even a relatively short time.

In the summer of 2005, maximum temperatures in some northern areas of the World Heritage Area went over the possum’s physiological tolerance for 27 days in a row. The population crashed. Tourist operators and others reported large numbers of dead possums.

“In that situation,” Williams says, “you can actually have all the individuals of that species die, on that day. Bang. Dead. Lying on the ground.”

Part of the reason we know as much as we do about the effects of climate change is that in 2008 the previous Labor government set up a body called the National Climate Change Adaptation Research Facility (NCCARF) with funding of $50 million.

It studied a wide array of issues, such as health, infrastructure, social impacts and natural ecosystems.

“I was director of its Natural Ecosystems Network, involving some 2500 scientists and people from government agencies,” Williams says. “We had pretty good coverage across Australia, of marine, freshwater, terrestrial ecosystems.”

But the current conservative government progressively cut NCCARF’s funding, down to nothing this year. Another program, the National Environmental Research Program, funded Williams’ specific work in the Wet Tropics. But that money dried up, too.

“So our monitoring largely stopped, as of about a year ago,” he says.

There is every reason to suspect the current government would rather people didn’t know too much about the consequences of climate change. The climate sceptics of its right wing were instrumental in removing Malcolm Turnbull from the prime ministership. The Morrison government has abandoned any meaningful action on climate change, on the premise – the false premise, in the view of most experts, environmental, business and industry groups – that such action is incompatible with affordable electricity.

Ignoring reality, however, does not change reality. The voters in the Wentworth byelection recognised that last weekend. An exit poll of more than 1000 voters conducted for The Australia Institute found 78 per cent said climate concerns had some influence on their vote, 47 per cent said it had a lot of influence and 33 per cent said it was the main thing.

The release during the campaign of the latest report by the Intergovernmental Panel on Climate Change (IPCC), a synthesis of more than 6000 research papers, reflecting the overwhelming consensus the world’s climate scientists, no doubt sharpened the voters’ appreciation of the pressing reality. One degree more of global warming and the world’s coral reefs, including the Great Barrier Reef, will be all but gone.

Even so, “fair dinkum power” – Prime Minister Scott Morrison’s coded slogan for more coal-fired electricity – remains the government’s big focus. The IPCC report was not telling us what to do, Morrison said.

But thanks to the work of the CSIRO, Bureau of Meteorology, NCCARF, the Climate Council, and many others, we know quite a lot about the impacts of climate change in this country.

We know which areas of the natural environment will be particularly hard hit. The Wet Tropics is one. So are the very biodiverse border ranges of New South Wales and Queensland, where species face a similar problem to those of the Wet Tropics – nowhere to go but uphill. Likewise, the alpine areas of NSW and Victoria. A report to the Victorian government earlier this year found that by mid century that state’s high country could have natural snow cover for all but a handful of days each year.

The World Heritage wetlands of Kakadu could be wiped out by rising sea levels. The south-west of Western Australia, which has particularly high plant diversity, also is exceptionally vulnerable. The climate modelling suggests winter rainfall – and most of the rain in that part of the country comes in winter – could decline as much as 50 per cent by 2090, in a worst-case scenario.

Across south-eastern Australia, cool season rain is projected to decline 10 to 20 per cent. Droughts will become more frequent and severe, not only because of declining and less regular rainfall but because evaporation rates increase with temperature. Fire seasons will lengthen.

Cyclones may not become more frequent, but will likely be more intense and blow further south. Because warmer air can hold more moisture, when it does rain it will likely be more intense. Australia’s extremes of climate, its “drought and flooding rains”, will be exacerbated.

The science indicates different effects of climate change in different parts of the country. Some, particularly in the north-west, will get wetter, while others will get drier. The common factor, though, is that everywhere it will get hotter. While some species may benefit, whole ecosystems and their component species will shift or expire.

“We are a mega-diverse country,” says James Trezise, a policy analyst with the Australian Conservation Foundation, “meaning we have a lot of wildlife that occurs nowhere else on Earth. Endemic species with limited dispersal options and small ranges are particularly vulnerable to extinction from climate impacts.

“The fact that we have the first documented mammal extinction globally due to climate change in the 21st century should ring alarm bells.

“As a safeguard, we need to be planning out where species and ecosystems will be moving and tailoring our conservation actions to meet that challenge. This means establishing new protected areas and connecting habitats to ensure we have a climate-smart safety net for nature, looking at protecting critical habitats such as climate refugia and building climate adaptation into our management actions.

“All of this requires substantial government investment, but sadly we’ve seen huge cuts to environment and climate programs, including the axing of the National Climate Change Adaptation Research Facility.”

Perhaps, though, instead of talking about the intrinsic value of the natural environment we should talk in terms governments understand: money.

The cost of the current drought could be up to $12 billion, according to a recent estimate by Commonwealth Bank. Even the once reliably conservative rural sector now accepts climate change is playing a part in this disaster. Like native species, agriculture will have to adapt and shift with the new climate reality.

One might question, for example, the wisdom of continuing to grow thirsty crops such as cotton on the increasingly water-starved Darling River basin. Large areas of formerly marginal crop land, as in the wheat belt of Western Australia, will likely become unviable.

Most of Australia’s population is concentrated near the coast, and will retreat as sea level rises and amid greater storm surges. A report a few years ago by the Climate Council assessed the costs of coastal flooding from sea level rises of 40 centimetres and one metre over the next century, and estimated it could be as much as $200 billion dollars.

One industry that keeps a close eye on such costs is the insurance industry.

The basic metric for it is simple.

“Extreme weather leads to loss, which leads to claims, which leads to higher premiums,” says Karl Sullivan, general manager for policy, risk and disaster planning at the Insurance Council of Australia.

“We have been working hard at identifying where the red dots are on the map, where a property already has an acute level of weather risk, and what can be done to bring risks down.”

Their work on identifying risk, he says, goes down to individual addresses and premiums are set accordingly. He provides an example of what happens when the risk is seen as just too great.

“Roma in Queensland had three one-in-a-hundred year floods in three successive years. One insurer had $124 million of losses for only $8 million of premium income. Most of the market stopped underwriting in Roma as a result.”

Then a levee was built, at a cost of some $20 million.

“The day the ribbon was cut insurance prices fell an average of 35 per cent and some by 73 per cent.”

But in many other places, mitigation action has not happened. He cites Lismore, in northern NSW.

“It has a completely inadequate flood defence system. Flood risks are extremely high and people who want to protect themselves are paying very high premiums,” Sullivan says.

As in Roma, mitigation would require tens of millions to be spent on a levee.

“You can apply that in a broader sense to climate change. In 50 years’ time, we know some of those risks are going to be so high that either people won’t be living there anymore, or we won’t be able to provide products that people can conceivably afford. If you start mitigating now, insurance can remain affordable and available.”

Sullivan points to research done by the Australian Business Roundtable for Disaster Resilience and Safer Communities, an industry group set up in 2012 in response to an unprecedented series of floods, storms and bushfires.

It found that the Australian government invests only about $50 million each year on mitigation measures, but more than 10 times that on post-loss recovery.

There are other costs, too. Professor Kingsley Faulkner, an eminent surgeon and chair of Doctors for the Environment, ticks off some of the health consequences:

“First, heatwaves. Every single city in this country will have many more days each year over 35 degrees. Over the past 100 years, more people have died of heat-related causes than any other natural problem.

“Then, changes in disease patterns. Things like malaria, dengue, Ross River virus, will likely move south with increasing temperatures. Many bacterial diseases are aggravated by heat and more common in tropical and subtropical areas.

“There also are effects on air quality and the emissions from fossil fuels. There’s an estimated 3000 deaths per annum from air pollution in Australia.”

The cost of air pollution due to the burning of coal in Australia is estimated at some $2.6 billion a year.

And there are mental health costs associated with the increased incidence of “natural” disasters. Increased suicide rates among drought-stricken farmers, children traumatised by the destruction of their homes.

Faulkner echoes the views of former Liberal leader John Hewson, who campaigned against his old party in Wentworth.

“No party should be elected without a credible climate policy,” Faulkner says.

“The latest IPCC report shows the absolute urgency of the issue. We wasted a decade, and this report says the next decade will be absolutely crucial. Unfortunately, in spite of the Wentworth result, this lot don’t seem to have learnt. They are still talking about subsidising coal, and having no strong emissions policy. They are appallingly inept.”

And the current sloganeering around “fair dinkum” power amounts to “stupidity”.

“We are playing around with the lives of our children and grandchildren – we really are,” Faulkner says.

On the upside, since Wentworth some of the more enlightened members of the Morrison government – Western Australian Senator Dean Smith most recently – have joined the growing chorus of voices – including BHP, the Australian Institute of Company Directors, the Business Council of Australia, Australian Industry Group, Australian Council of Social Service, St Vincent de Paul and others – advocating serious policy.

Smith set out the issue in political terms. The conservative parties could either shift their position or lose a whole generation of voters.

But the likes of Smith are still in the minority in this government. And the polls all suggest that six months from now, maybe less, the Morrison government will go the way of the Bramble Cay melomys: washed away by the rising tide.