Street trees usually grow in appalling soils, have little space for their roots, are rarely watered and often get aggressively trimmed by road authorities or utility companies.
If they do get established, many street trees suffer damage from vehicles, have to live in wind tunnels or are forced to grow in the permanent shade of large buildings.
But despite everything we throw at them, many street trees don’t just survive, they thrive. So let’s meet one of these heroic species: the yellow gum, (Eucalyptus leucoxylon).
Pretty but tough
Yellow gum is widely planted across southeastern and eastern Australia as a street tree. In some suburbs and towns, it is so common that people think it is a native tree (in fact it is from South Australia, Victoria or southwest New South Wales).
It is not to be confused with yellow box (Eucalyptus melliodora), a different eucalypt altogether.
Yellow gum has been widely planted because it meets many of the demands we place on urban trees.
It’s called yellow gum in Victoria and parts of NSW, but is often known as blue gum in SA.
The common names can be confusing, but yellow gum refers to its pale yellow wood and bark patches, while blue gum refers to its leaves.
Many specimens develop dense, low, spreading canopies, which offer lovely shade and help cool our cities down.
And importantly, it doesn’t grow too big. It is typically a medium to small woodland tree, usually between 13 and 16 metres high (but it can grow higher in the wild).
Yellow gum has an attractive smooth trunk with yellow, blue-grey or cream patches.alybaba/Shutterstock
Different bird and insect species feed on the trees some feeding on flowers and fruits and others on the foliage.
Natural populations of yellow gum occur in coastal and inland SA, in the southwest corner of NSW and in the western half of Victoria from the Murray River to the coast.
There are several subspecies, too, and debate rages in botanical and horticultural circles about whether some of them deserve to be recognised as their own species.
Yellow gum is also tolerant of wind and salt spray, and can withstand waterlogged soils. They stood up to the millennium drought conditions well.
Many arborists think the yellow gum has the potential to do well in many parts of Australia as the climate changes. Research has shown, for example, that some individual yellow gum trees regulate their water use better (when compared to other individuals in the species, and when compared to other eucalypts).
Like many eucalypts, yellow gum possesses lots of dormant buds and a lignotuber (a swelling at the base of the trunk containing dormant buds and carbohydrate). This means it copes well with pruning and will respond especially well to targeted formative pruning when young.
This can help reduce the risk of problems such as what’s known as “co-dominant stems” (when two main stems grow from a single point of origin, instead of one tall, straight trunk) and rubbing or crossing branches.
Not everyone’s favourite
Not everybody likes the yellow gum, and for some good reasons.
Some yellow gums are multi-stemmed, while others have twisted and curving trunks; some have both. These are not the characteristics many local governments want in street trees; many want to see straight trunks and dense canopies.
Yellow gums often produce a lovely dense canopy.Gregory Moore
These problems can be so annoying that some council arborists no longer recommend planting yellow gums.
But these issues are due to poor tree selection and propagation. In the past, yellow gum seed was not carefully sourced from the best trees with the most suitable characteristics, and so inferior specimens have prospered.
With the right investment of time and money into tree selection, these problems can be overcome.
Ticking most of the boxes
All in all, yellow gum can be a very fine and useful urban tree.
The species grows well and if superior stock is used, the trees develop with straight and attractive trunks and wide, dense canopies.
They are typically medium-sized trees, do well in tough street conditions or in smaller domestic front and back yards.
They tick most, if not all, of the boxes for a good urban street tree.
Gregory Moore does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Composite image, Xiangli Li, Shirley Jayne Photography and geckoz/Shutterstock
Australia’s 2022 federal election was seen as the climate election. But this time round, climate policy has so far taken a back seat as the major parties focus on cost-of-living issues.
Despite this, climate change remains an ever-present threat. Last year was the world’s hottest on record and extreme weather is lashing Queensland. But there are hints of progress. Australia’s emissions have begun to fall and the main power grid is now 40% renewable.
So before Australians head to the polls on May 3, it’s worth closely examining the climate policies of the two major parties. What are they offering on cutting emissions, preparing for climate-boosted disasters and future-proofing our energy systems? And where are the gaps?
Energy transition – Tony Wood, Grattan Institute
Cost-of-living pressures, escalating damage from climate change and global policy uncertainty mean no election issue is more important than transforming Australia’s economy to achieve net zero. But our energy supply must be reliable and affordable. What should the next government prioritise?
There is great pressure to deliver power bill relief. But the next government’s priority should be reducing how much a household spends on energy, rather than trying to bring down the price of electricity. Far better to give financial support for battery storage and better home insulation, to slash how much power consumers need to buy from the grid.
The Liberal-led Senate inquiry has just found supporting home electrification will also help with cost of living pressures.
The electricity rebates on offer from Labor and the temporary cut to fuel excise from the Coalition aren’t enough.
Federal and state governments must maintain their support and investment in the new transmission lines necessary to support new renewable generation and storage.
Labor needs to do more to meet its 2030 target of reaching 82% renewables in the main grid. Currently, the figure is around 40%. The Coalition’s plan to slow down renewables, keep coal going longer and burn more gas while pushing for a nuclear future carries alarmingly high risks on reliability, cost and environmental grounds.
Gas shortfalls are looming for Australia’s southeast in the next few winters and the price of gas remains stubbornly high. Labor does not yet have a workable solution to either issue, while the Coalition has an idea – more and therefore cheaper gas – but no clarity on how its plan to keep more gas for domestic use would work in practice.
So far, we have been offered superficially appealing ideas. The field is wide open for a leader to deliver a compelling vision and credible plan for Australia’s net-zero future.
Climate adaptation – Johanna Nalau, Griffith University
You would think adapting to climate change would be high on the election agenda. Southeast Queensland just weathered its first cyclone in 50 years, estimated to have caused A$1.2 billion in damage, while outback Queensland is enduring the worst flooding in 50 years.
But so far, there’s little to see on adaptation.
Both major parties have committed to building a weather radar in western Queensland, following local outcry. While welcome, it’s a knee-jerk response rather than good forward planning.
By 2060, damage from climate change will cost Australia $73 billion a year under a low emissions scenario, according to a Deloitte report. The next federal government should invest more in disaster preparation rather than throwing money at recovery. It’s cheaper, for one thing – longer term, there are significant savings by investing in more resilient infrastructure before damage occurs.
Being prepared requires having enough public servants in disaster management to do the work. The Coalition has promised to cut 41,000 jobs from the federal public service, and has not yet said where the cuts would be made.
Regardless of who takes power, these will be useful roadmaps to manage extreme weather, damage to agriculture and intensified droughts, floods and fires. Making sure climate-exposed groups such as farmers get necessary assistance to weather worse disasters, and manage new risks and challenges stemming from climate change, is not a partisan issue. Such plans will help direct investment towards adaptation methods that work at scale.
New National Science Priorities are helpful too, especially the focus on new technologies able to sustainably meet Australia’s food and water needs in a changing climate.
Intensifying climate change brings more threats to our food systems and farmers.Shirley Jayne Photography
Emission reduction – Madeline Taylor, Macquarie University
Emission reduction has so far been a footnote for the major parties. In terms of the wider energy transition, both parties are expected to announce policies to encourage household battery uptake and there’s a bipartisan focus on speeding up energy planning approvals.
But there is a clear divide in where the major parties’ policies will lead Australia on its net-zero journey.
Labor’s policies largely continue its approach in government, including bringing more clean power and storage into the grid within the Capacity Investment Scheme and building new transmission lines under the Rewiring Australia Plan.
These policies are leading to lower emissions from the power sector. Last year, total emissions fell by 0.6%. Labor’s Future Made in Australia policies give incentives to produce critical minerals, green steel, and green manufacturing. Such policies should help Australia gain market share in the trade of low-carbon products.
From January 1 this year, Labor’s new laws require some large companies to disclose emissions from operations. This is positive, giving investors essential data to make decisions. From their second reporting period, companies will have to disclose Scope 3 emissions as well – those from their supply chains. The laws will cover some companies where measuring emissions upstream is incredibly tricky, including agriculture. Coalition senators issued a dissenting report pointing this out. The Coalition has now vowed to scrap these rules.
The Coalition has not committed to Labor’s target of cutting emissions 43% by 2030. Their flagship plan to go nuclear will likely mean pushing out emissions reduction goals given the likely 2040s completion timeframe for large-scale nuclear generation, unless small modular reactors become viable.
On gas, there’s virtually bipartisan support. The Coalition promise to reserve more gas for domestic use is a response to looming shortfalls on the east coast. Labor has also approved more coal and gas projects largely for export, though Australian coal and gas burned overseas aren’t counted domestically.
Opposition Leader Peter Dutton has promised to include gas in Labor’s renewable-oriented Capacity Investment Scheme and has floated relaxing the Safeguard Mechanism on heavy emitters. The Coalition has vowed to cancel plans for three offshore wind projects and are very critical of green hydrogen funding.
Both parties will likely introduce emission reduction measures, but a Coalition government would be less stringent. Scrapping corporate emissions reporting entirely would be a misstep, because accurate measurement of emissions are essential for attracting green investment and reducing climate risks.
Johanna Nalau has received funding from Australian Research Council for climate adaptation research, is a Lead Author of the Intergovernmental Panel on Climate Change, Co-chair of the Science Committee of the World Adaptation Science Program (United Nations Environment Programme) and is a technical expert with United Nations Framework Convention on Climate Change
Madeline Taylor has received funding from the Australian Research Council, ACOLA, and several industry and government partners for energy transition research. She is a board member of REAlliance, Fellow of the Climate Council, and Honorary Associate of the Sydney Environment Institute.
Tony Wood may own shares in companies in relevant industries through his superannuation fund
Picture this: you’re lounging on a beautiful beach, soaking up the sun and listening to the soothing sound of the waves. You run your hands through the warm sand, only to find a cigarette butt. Gross, right?
This disturbing scene is typical of coastal pollution in Australia. But fortunately our new research shows the problem is getting better, not worse. Over the past ten years, the amount of waste across Australian coastal cities has reduced by almost 40%. We’re also finding more places with no rubbish at all.
We surveyed for debris in and around six Australian urban areas between 2022 and 2024. Then we compared our results to previous surveys carried out a decade ago. We found less coastal pollution overall and reset a new baseline for further research.
Our study shows efforts to clean up Australia’s beaches have been working. These policies, practices and outreach campaigns have reduced the extent of pollution in coastal habitats near urban centres. But we can’t become complacent. There’s plenty of work still to be done.
One of the many beaches surveyed by CSIRO.TJ Lawson
What we did
In Australia, three-quarters of the rubbish on our coasts is plastic. Even cigarette butts are mainly made of plastic.
To tackle the pollution effectively, we need to understand where the waste is coming from and how it gets into the environment.
Research has shown much of the coastal debris comes from local inland areas. Poor waste management practices can result in debris eventually making its way through rivers to the coast and out to sea.
We focused on urban areas because high population density and industrial activity contributes to waste in the environment. We examined six areas across Australia:
Perth in Western Australia
Port Augusta in South Australia
Hobart in Tasmania
Newcastle in New South Wales
Sunshine Coast in Queensland
Alice Springs in the Northern Territory.
These places represent a starting point for the national baseline. At each location we studied sites on the coast, along rivers and inland, within a 100 kilometre radius.
We inspected strips of land 2m wide. This involved two trained scientists standing in an upright position looking downward, slowly walking along a line surveying for debris items. Together they captured information about every piece of debris they came across, including the type of material and what it was originally used for (where possible).
What we found
On average, we found 0.15 items of debris per square metre of land surveyed. That’s roughly one piece of rubbish every five steps.
Plastic was the most common type of waste. But in many cases it was unclear what the item was originally used for. For example, fragments of hard plastic of unknown origin were found in a quarter of all surveyed areas.
Polystyrene fragments were the most common item overall (24% of all debris fragments). Other frequently encountered items included food wrappers or labels, cigarette butts, and hard plastic bottle caps or lids.
We found more waste near farms, industry and disadvantaged areas.
The types of waste varied among cities. For example, cigarette butts were the most prevalent items in Newcastle, Perth and the Sunshine Coast. But food wrappers and beverage cans were more prevalent in Port Augusta and Alice Springs, respectively.
Hobart had the highest occurrence of beverage bottles and bottle fragments.
The most common type of waste varied among cities.CSIRO
Targeting problem items
Identifying the different types of litter in the environment can help policymakers and waste managers target specific items and improve waste recovery.
Research has shown container deposit legislation, which enables people to take eligible beverage containers to a collection point for a refund, has reduced the number of beverage containers in the coastal environment by 40%. Hobart did not have a container deposit scheme in place at the time of our survey.
Plastic bag bans can reduce bag litter. Now polystyrene food service items are becoming increasingly targeted by policymakers.
Hobart had the highest occurrence of beverage bottles and bottle fragments.Caroline Bray
Making progress
When we compared our results to the previous survey from 2011-14 we found a 39% decrease in coastal debris. We also found 16% more areas where no debris was present.
Our results support previous research that found an ongoing trend towards less waste on Australian beaches.
We think our research demonstrates the effectiveness of improved waste management policies, campaigns such as the “Five R’s – Refuse, Reduce, Reuse, Repurpose, then Recycle” – as well as clean-up efforts.
It’s likely that increased awareness is making a big dent in the problem. But reducing the production of plastic, and invoking changes further up the supply chain, would likely further help reduce mismanaged waste in the environment.
Implications for the future
Measuring and monitoring litter can inform policymaking and waste management. Our research serves as a benchmark for evaluating and informing future efforts to reduce plastic waste.
We are heartened by the findings. But continued effort is needed from people across government, industry and Australian communities. Everyone needs to address how we produce, use and dispose of plastic for a cleaner and healthier planet.
Australians are increasingly aware of the need to keep the coastal environment free of litter.Qamar Schuyler
As part of her role at CSIRO, Stephanie Brodie receives funding the federal Department of Climate Change, Energy, the Environment and Water, and the Australian Fisheries Management Authority.
Britta Denise Hardesty received funding for this work from the Department of Climate Change, Energy, Environment and Water. Shell Australia previously provided funding for this research via Earthwatch Australia for surveys and citizen science projects carried out between 2011 and 2014.
US President Donald Trump’s new trade war will not only send shockwaves through the global economy – it also upsets efforts to tackle the urgent issue of climate change.
Trump has announced a minimum 10% tariff to be slapped on all exports to the United States. A 34% duty applies to imports from China and a 20% rate to products from the European Union. Australia has been hit with the minimum 10% tariff.
The move has prompted fears of a global economic slowdown. This might seem like a positive for the climate, because greenhouse gas emissions are closely tied to economic growth.
However, in the long term, the trade war is bad news for global efforts to cut emissions. It is likely to lead to more energy-intensive goods produced in the US, and dampen international investment in renewable energy projects.
How does global trade affect emissions?
Traditionally, growth in the global economy leads to greater emissions from sources such as energy use in both manufacturing and transport. Conversely, emissions tend to fall in periods of economic decline.
Trade tensions damage the global economy. This was borne out in the tariff war between the US and China, the world’s two largest economies, in 2018 and 2019.
Trump, in his first presidential term, imposed tariffs on billions of dollars worth of imports from China. In response, China introduced or increased tariffs on thousands of items from the US.
As a result, the International Monetary Fund estimated global gross domestic product (GDP) would fall by 0.8% in 2020. The extent of its true impact on GDP is difficult to determine due to the onset of COVID in the same year.
However, Trump’s tariff war is far broader this time around, and we can expect broadscale damage to global GDP.
In the short-term, any decline is likely to have a positive impact on emissions reduction. We saw this effect during the COVID-19 pandemic, when global production and trade fell.
But unfortunately, this effect won’t last forever.
Domestic production isn’t always a good thing
Every country consumes goods. And according to Trump’s trade plan, which aims to revive the US manufacturing base, the goods his nation requires will be produced domestically rather than being imported.
Unfortunately, this US production is likely to be inefficient in many cases. A central tenet of global trade is that nations focus on making goods where they have a competitive advantage – in other words, where they can manufacture the item more cheaply than other nations can. That includes making them using less energy, or creating fewer carbon emissions.
If the US insists on manufacturing everything it needs domestically, we can expect many of those goods to be more emissions-intensive than if they were imported.
Renewable energy slowdown?
Globally, investment in renewable energy has been growing. The US trade war jeopardises this growth.
Renewable energy spending is, in many cases, a long-term investment which may not produce an immediate economic reward. The logic is obvious: if we don’t invest in reducing emissions now, the economic costs in the future will be far worse.
However, the US tariffs create a new political imperative. Already, there are fears it may trigger a global economic recession and increase living costs around the world.
National governments are likely to become focused on protecting their own populace from these financial pressures. Business and industry will also become nervous about global economic conditions.
And the result? Both governments and the private sector may shy away from investments in renewable energy and other clean technologies, in favour of more immediate financial concerns.
The COVID experience provides a cautionary tale. The unstable economic outlook and higher interest rates meant banks were more cautious about financing some renewable energy projects.
And according to the International Energy Agency, small to medium-sized businesses became more reluctant to invest in renewable energy applications such as heat pumps and solar panels.
What’s more, the slowing in global trade during the pandemic meant the supply of components and materials vital to the energy transition was disrupted.
There are fears this disruption may be repeated following the US tariff move. For example, the duty on solar products from China to the US is expected to rise to 60%, just as demand for solar energy increases from US data centres and artificial intelligence use.
Few nations can afford to impose retaliatory tariffs on US imports.
Prime Minister Anthony Albanese, for example, said Australia would not follow suit, adding the move would be “a race to the bottom that leads to higher prices and slower growth”.
China, however, can be expected to return fire. Already it has halted imports of liquefied natural gas (LNG) from the US for 40 days – a move attributed to trade tensions.
This may seem like good news for emissions reduction. However, China, like all other nations, needs energy. With less gas from the US, it may resort to burning more coal – which generates more CO? when burnt than gas.
Prime Minister Anthony Albanese responds to Trump’s tariff announcement.
And, with the right safeguards in place, global trade can help drive the clean energy transition. Global trade improves efficiency and innovation and technology. This is likely to benefit innovation in clean energy and energy efficiency.
Trump’s tariff war weakens global trade, and will slow the world’s progress towards decarbonisation. It is a most uncertain time – both for the world’s economy, and its climate.
Rakesh Gupta does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Locals in renewable energy hotspots say they have been forced to create their own information groups to address concerns about the rapid energy transition and want the government to pitch in.
The greater bilby (Macrotis lagotis) is one of Australia’s most iconic yet at-risk animals — and the last surviving bilby species. Once found across 70% of Australia, its range has contracted by more than 80% since European colonisation.
Today, these nocturnal marsupials, still culturally significant to many Indigenous peoples, are restricted to remote deserts. They face an ongoing threat of extinction.
Local elders, Indigenous rangers and scientists hold valuable knowledge about bilby populations, the threats they face, and strategies needed to sustain them into the future.
Our new study, published today in Conservation Science and Practice, reveals how collaboration between scientists and Indigenous land managers can help yield new and vital information.
In the field, we used two methods – one based on Warlpiri knowledge and one based on standard scientific protocols – to locate bilbies and collect scat (poo) samples in the North Tanami Indigenous Protected Area in the Northern Territory.
By drawing on Warlpiri tracking expertise and Western scientific methods, we uncovered crucial information on bilby populations that could help conserve these rare creatures.
Understanding bilby numbers is important – but hard
Bilbies turn over tonnes of soil each year, helping to improve soil health, help seeds germinate and enhance water infiltration. Their deep, complex burrows also provide shelter for other species.
They’re crucial to the health of desert ecosystems; protecting bilbies means protecting the web of life they support.
To do this, we need to know more about:
how many bilbies there are
how they respond to land management techniques such as planned burning
how they respond to threats such as feral predators.
Yet, bilbies are notoriously difficult to monitor directly via live capture. They’re nocturnal, shy and solitary. And they inhabit vast landscapes, making it very hard to estimate population numbers.
Bilby tracks North Tanami (pen for scale).Hayley Geyle/Author Provided
Luckily, the tracks, diggings and scats bilbies leave behind provide ample clues. DNA from scat (if it can be found) can be used to estimate how many bilbies are present in a particular area.
Systematic ecological surveys, often used to monitor wildlife, can be rigid and expensive, especially in remote regions.
We need flexible methods that align with local knowledge and the practical realities of monitoring bilbies on Country.
A new approach to monitor and manage bilbies
We tested two methods of locating bilby scat for DNA analysis.
The first was systematic sampling. This is a standard scientific approach where fixed lengths of land were walked multiple times to collect scat.
This ensures sampling effort is even over the search area and comparable across sites. However, like most species, bilby distribution is patchy, and this approach can lead to researchers missing important signs.
The second method was targeted sampling, guided by Warlpiri knowledge, to search in areas most likely to yield results.
This allowed the search team to focus on areas where bilbies were active or predicted to be active based on knowledge of their habits and food sources.
Altogether, we collected more than 1,000 scat samples. In the lab, we extracted DNA from these samples to identify individual bilbies. These data, combined with the location of samples, allowed us to estimate the size of the bilby population.
We then compared estimates that would have been derived if we had only done systematic or targeted sampling, or both, to assess their strengths and limitations for monitoring bilby populations.
The deep, complex burrows of bilbies also provide shelter for other species.Kelly Dixon/Author provided
What we found
We identified 20 bilbies from the scats collected during systematic surveys and 26 – six more – from targeted surveys. At least 16 individual bilbies were detected by both methods. In total, we confirmed 32 unique bilbies in the study area.
When it came to population estimates – which consider how many repeat captures occur and where – combining data from both types of surveys produced the most accurate estimates with the least effort.
Targeted sampling tended to overestimate population size because it focused on areas of high activity. Systematic sampling was more precise but required greater effort.
Combining both approaches provided the most reliable estimates while saving time.
In the lab, we extracted DNA from bilby scat samples to identify individual bilbies.Hayley Geyle/Author provided
What this means for conservation
Our research highlights how collaboration that includes different ways of knowing can improve conservation.
By adapting standard on-ground survey techniques to include Warlpiri methods for tracking bilbies, we produced better data and supported local capacity for bilby monitoring.
Conservation programs often rely on standardised ecological monitoring protocols – in other words, doing things much the same way no matter where you’re working.
While these protocols provide consistency, they are rigid and don’t always yield the best results. They also fail to incorporate local knowledge crucial for managing species like the bilby.
Our approach shows how integrating diverse ways of working can deliver more inclusive and effective outcomes, without compromising data reliability.
Their future depends on collaborative efforts that draw on scientific and Indigenous and local knowledges.
This study provides an example of how such partnerships can work – not just for bilbies, but for other species and ecosystems.
As Australia confronts biodiversity loss, this research underscores the importance of listening to those who know Country best.
By valuing and respecting local expertise, we can build a stronger future for bilbies and the landscapes that are their home.
Hayley Geyle is employed by Territory NRM, who receives funding for threatened species projects from the Australian government through the Natural Heritage Trust. She also works on the Digital Women Ranger project. She is affiliated with Territory NRM and the Northern Institute (Charles Darwin University).
Cathy Robinson is employed at CSIRO and is Group Leader in the Agriculture and Food Sustainability Program and Research lead for the Digital Women Ranger Program which is supported by the Telstra Foundation. Cathy is also an Adjunct Professor at Charles Darwin University, Chair of IUCN Australian Expert Advisory Panel for the Green List, and Executive Advisor for the Liveris Academy for Innovation and Leadership at the University of Queensland.
Christine Schlesinger does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Helen Wilson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
After trespassers vandalised Koonalda Cave on the Nullarbor Plain a round-the-clock surveillance system was installed to help protect the nationally significant heritage site.
If you go walking in the wild, you might expect that what you’re seeing is natural. All around you are trees, shrubs and grasses growing in their natural habitat.
But there’s something here that doesn’t add up. Across the world, there are large areas of habitat which would suit native plant species just fine. But very often, they’re simply absent.
Our new research gauges the scale of this problem, known as “dark diversity”. Our international team of 200 scientists examined plant species in thousands of sites worldwide.
What we found was startling. In regions heavily affected by our activities, only about 20% of native plant species able to live there were actually present. But even in areas with very little human interference, ecosystems only contained about 33% of viable plant species.
Why so few species in wilder areas? Our impact. Pollution can spread far from the original source, while conversion of habitat to farms, logging and human-caused fires have ripple effects too.
Conspicuous by their absence
Our activities have become a planet-shaping force, from changing the climate through our emissions to farming 44% of all habitable land. As our footprint has expanded, other species have been pushed to extinction. The rates of species loss are unprecedented in recorded history.
When we think about biodiversity loss, we might think of a once-common animal species losing numbers and range as farms, cities and feral predators expand. But we are also losing species from within protected areas and national parks.
To date, the accelerating loss of species has been largely observed at large scale, such as states or even whole countries. Almost 600 plant species have gone extinct since 1750 – and this is likely a major underestimate. Extinction hotspots include Hawaii (79 species) and South Africa’s unique fynbos scrublands (37 species).
But tracking the fate of our species has been difficult to do at a local scale, such as within a national park or nature reserve.
Similarly, when scientists do traditional biodiversity surveys, we count the species previously recorded in an area and look for changes. But we haven’t tended to consider the species that could grow there – but don’t.
Many plants have been declining so rapidly they are now threatened with extinction.
What did we do?
To get a better gauge of biodiversity losses at smaller scale, we worked alongside scientists from the international research network DarkDivNet to examine almost 5,500 sites across 119 regions worldwide. This huge body of fieldwork took years and required navigating global challenges such as COVID-19 and political and economic instability.
At each 100 square metre site, our team sampled all plant species present against the species found in the surrounding region. We defined regions as areas of approximately 300 square kilometres with similar environmental conditions.
Just because a species can grow somewhere doesn’t mean it would. To make sure we were recording which species were genuinely missing, we looked at how often each absent species was found growing alongside the species growing at our chosen sites at other sampled sites in the region. This helped us detect species well-suited to a habitat but missing from it.
We then cross-matched data on these missing species against how big the local human impact was by using the Human Footprint Index, which measures population density, land use and infrastructure.
Of the eight components of this index, six had a clear influence on how many plant species were missing: human population density, electric infrastructure, railways, roads, built environments and croplands. Another component, navigable waterways, did not have a clear influence.
Interestingly, the final component – pastures kept by graziers – was not linked to fewer plant species. This could be because semi-natural grasslands are used as pasture in areas such as Central Asia, Africa’s Sahel region and Argentina. Here, long-term moderate human influence can actually maintain highly diverse and well-functioning ecosystems through practices such as grazing livestock, cultural burning and hay making.
Semi-natural pastures preserve many different plant species. Pictured: the Hulunbuir grasslands in Inner Mongolia, China.Dashu Xinganling/Shutterstock
Overall, though, the link between greater human presence and fewer plant species was very clear. Seemingly pristine ecosystems hundreds of kilometres from direct disturbance had been affected.
These effects can come from many causes. For instance, poaching and logging often take place far from human settlements. Poaching an animal species might mean a plant species loses a key pollinator or way to disperse its seeds in the animal’s dung. Over time, disruptions to the web of relationships in the natural world can erode ecosystems and result in fewer plant species. Poachers and illegal loggers also cut “ghost roads” into pristine areas.
Other causes include fires started by humans, which can threaten national parks and other safe havens. Pollution can travel and settle hundreds of kilometres from its source, affecting ecosystems.
Our far-reaching influence can also hinder the return of plant species, even in protected areas. As humans expand their activities, they often carve up natural areas into fragments cut off from each other. This can isolate plant populations. Similarly, the loss of seed-spreading animals can stop plants from recolonising former habitat.
What does this mean?
Biodiversity loss is not just about species going extinct. It’s about ecosystems quietly losing their richness, resilience and functions.
Protecting land is not enough. The damage we can do can reach deep into conservation areas.
Was there good news? Yes. In regions where at least a third of the landscape had minimal human disturbance, there was less of this hidden biodiversity loss.
As we work to conserve nature, our work points to a need not just to preserve what’s left but to bring back what’s missing. Now we know what species are missing in an area but still present regionally, we can begin that work.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
Australia is a place of great natural beauty, home to many species found nowhere else on Earth. But it’s also particularly vulnerable to introduced animals, diseases and weeds. Habitat destruction, pollution and climate change make matters worse. To conserve what’s special, we need far greater care.
Unfortunately, successive federal governments have failed to protect nature. Australia now has more than 2,000 threatened species and “ecological communities” – groups of native species that live together and interact. This threatened list is growing at an alarming rate.
The Albanese government came to power in 2022 promising to reform the nation’s nature laws, following a scathing review of the laws. But it has failed to do so.
But scientific evidence suggests much more is required to protect Australia’s natural wonders.
Fighting invaders
Labor has made a welcome commitment of more than A$100 million to counter “highly pathogenic avian influenza”. This virulent strain of bird flu is likely to kill millions of native birds and other wildlife.
The government also provided much-needed funding for a network of safe havens for threatened mammals. These safe-havens exclude cats, foxes and other invasive species.
But much more needs to be done. Funding is urgently needed to eradicate red imported fire ants, before eradication becomes impossible. Other election commitments to look for include:
national coordination and leadership to stop the indiscriminate use of poisons that can spread through ecosystems and food-chains, killing non-target animals such as owls, quolls, Tasmanian devils, reptiles and frogs.
Stopping land clearing and habitat destruction
The states are largely responsible for controlling land clearing. But when land clearing affects “matters of national environmental significance” such as a nationally listed threatened species or ecological community, it becomes a federal matter.
Such proposals are supposed to be referred to the federal environment minister for assessment under the Environment Protection and Biodiversity Conservation (EPBC) Act.
Only about 1.5% of the hundreds of thousands of hectares of land cleared in Australia every year is fully assessed under the EPBC Act.
This means our threatened species and ecological communities are suffering a “death by a thousand cuts”.
How do we fix this? A starting point is to introduce “national environmental standards” of the kind envisaged in the 2020 review of the EPBC Act by Professor Graeme Samuel.
Habitat destruction at Lee Point, Darwin.Martine Maron
Protecting threatened species
For Australia to turn around its extinction crisis, prospective elected representatives and governments must firmly commit to the following actions.
Stronger environmental law and enforcement is essential for tackling biodiveristy decline and extinction. This should include what’s known as a “climate trigger”, which means any proposal likely to produce a significant amount of greenhouse gases would have to be assessed under the EPBC Act.
This is necessary because climate change is among the greatest threats to biodiversity. But the federal environment minister is currently not legally bound to consider – or authorised to refuse – project proposals based on their greenhouse gas emissions. In an attempt to pass the EPBC reforms in the Senate last year, the Greens agreed to postpone their demand for a climate trigger.
A large increase in environmental spending – to at least 1% of the federal budget – is vital. It would ensure sufficient support for conservation progress and meeting legal requirements of the EPBC Act, including listing threatened species and designing and implementing recovery plans when required.
Show nature the money!
Neither major party has committed to substantial increases in environmental spending in line with what experts suggest is urgently needed.
Without such increased investment Australia’s conservation record will almost certainly continue to deteriorate. The loss of nature hurts us all. For example, most invasive species not only affect biodiversity; they have major economic costs to productivity.
Whoever forms Australia’s next government, we urge elected leaders to act on the wishes of 96% of surveyed Australians calling for more action to conserve nature.
Euan Ritchie receives funding from the Australian Research Council and the Department of Energy, Environment, and Climate Action. Euan is a Councillor within the Biodiversity Council, a member of the Ecological Society of Australia and the Australian Mammal Society, and President of the Australian Mammal Society.
John Woinarski is a Professor at Charles Darwin University, a director of the Australian Wildlife Conservancy, co-chair of the IUCN Australasian Marsupials and Monotremes Specialist group, a councillor with the Biodiversity Council, and a member of the science advisory committee of Zoos Victoria and Invertebrates Australia. He has received funding from the Australian government to contribute to the management of feral cats and foxes.
Martine Maron has received funding from various sources including the Australian Research Council, the Queensland Department of Environment and Science, and the federal government's National Environmental Science Program, and has advised both state and federal government on conservation policy. She is a member of the Wentworth Group of Concerned Scientists, a director of the Australian Wildlife Conservancy, a councillor with the Biodiversity Council, and leads the IUCN's thematic group on Impact Mitigation and Ecological Compensation under the Commission on Ecosystem Management.
The damage climate change will inflict on the world’s economy is likely to have been massively underestimated, according to new research by my colleagues and I which accounts for the full global reach of extreme weather and its aftermath.
To date, projections of how climate change will affect global gross domestic product (GDP) have broadly suggested mild to moderate harm. This in part has led to a lack of urgency in national efforts to reduce greenhouse gas emissions.
However, these models often contain a fundamental flaw – they assume a national economy is affected only by weather in that country. Any impacts from weather events elsewhere, such as how flooding in one country affects the food supply to another, are not incorporated into the models.
Our new research sought to fix this. After including the global repercussions of extreme weather into our models, the predicted harm to global GDP became far worse than previously thought – affecting the lives of people in every country on Earth.
Weather shocks everywhere, all at once
Global warming affects economies in many ways.
The most obvious is damage from extreme weather. Droughts can cause poor harvests, while storms and floods can cause widespread destruction and disrupt the supply of goods. Recent research has also shown heatwaves, aggravated by climate change, have contributed to food inflation.
Most prior research predicts that even extreme warming of 4°C will have only mild negative impacts on the global economy by the end of the century – between 7% and 23%.
Such modelling is usually based on the effects of weather shocks in the past. However, these shocks have typically been confined to a local or regional scale, and balanced out by conditions elsewhere.
For example, in the past, South America might have been in drought, but other parts of the world were getting good rainfall. So, South America could rely on imports of agricultural products from other countries to fill domestic shortfalls and prevent spikes in food prices.
But future climate change will increase the risk of weather shocks occurring simultaneously across countries and more persistently over time. This will disrupt the networks producing and delivering goods, compromise trade and limit the extent to which countries can help each other.
International trade is fundamental to the global economic production. So, our research examined how a country’s future economic growth would be influenced by weather conditions everywhere else in the world.
What did we find?
One thing was immediately clear: a warm year across the planet causes lower global growth.
We corrected three leading models to account for the effects of global weather on national economies, then averaged out their results. Our analysis focused on global GDP per capita – in other words, the world’s economic output divided by its population.
We found if the Earth warms by more than 3°C by the end of the century, the estimated harm to the global economy jumped from an average of 11% (under previous modelling assumptions) to 40% (under our modelling assumptions). This level of damage could devastate livelihoods in large parts of the world.
Previous models have asserted economies in cold parts of the world, such as Russia and Northern Europe, will benefit from warmer global temperatures. However, we found the impact on the global economy was so large, all countries will be badly affected.
A warm year across the planet causes lower global growth. Pictured: wilted corn crops during drought.wahyusyaban/Shutterstock
Costs vs benefits
Reducing emissions leads to short-term economic costs. These must be balanced against the long-term benefits of avoiding dangerous climate change.
Recent economic modelling has suggested this balance would be struck by reducing emissions at a rate that allows Earth to heat by 2.7°C.
This is close to Earth’s current warming trajectory. But it is far higher than the goals of the Paris Agreement, and global warming limits recommended by climate scientists. It is also based on the flawed assumptions discussed above.
Under our new research, the optimal amount of global warming, balancing short-term costs with long-term benefits, is 1.7°C – a figure broadly consistent with the Paris Agreement’s most ambitious target.
Our new research shows previous forecasts of how such warming will affect the global economy have been far too optimistic. It adds to otherrecent evidence suggesting the economic impacts of climate change has been badly underestimated.
Clearly, Earth’s current emissions trajectory risks our future and that of our children. The sooner humanity grasps the calamities in store under severe climate change, the sooner we can change course to avoid it.
Timothy Neal does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
The small Queensland town of Eromanga bills itself as Australia’s town furthest from the sea. But this week, an ocean of freshwater arrived.
Monsoon-like weather has hit the normally arid Channel Country of inland Queensland. Some towns have had two years’ worth of rain in a couple of days. These flat grazing lands now resemble an inland sea.
One New South Wales man is still missing and dozens of people have been evacuated. Others are preparing to be cut off, potentially for weeks. And graziers are reporting major livestock losses – more than 100,000 and climbing. In some areas, the flooding is worse than 1974, the wettest year on record in Australia.
Why so much rain? Tropical, water-laden air has been brought far inland from the oceans to the north and east. This can happen under normal climate variability. But our ocean temperatures are the highest on record, which supercharges the water cycle.
In coming weeks, this huge volume of water will wend its way through the channels perhaps 600 km to fill Kati Thanda-Lake Eyre, the ephemeral lake which appears in the northern reaches of South Australia. It’s likely this will be a Lake Eyre for the ages.
In the first three months of the year, deadly record-breaking floods hit northern Queensland before Cyclone Alfred tracked unusually far south and made landfall in southeast Queensland, bringing widespread winds and rains and leaving expensive repair bills. Now the rain has come inland.
Why so much rain in arid areas?
Some meteorologists have dubbed this event a pseudo-monsoon. That’s because the normal Australian monsoon doesn’t reach this far south – the torrential rains of the monsoonal wet season tend to fall closer to the northern coasts.
Because the Arafura and Timor Seas to the north are unusually warm, evaporation rates have shot up. Once in the air, this water vapour makes for very humid conditions. These air masses are even more humid than normal tropical air, because they have flowed down from the equator. Many Queenslanders can vouch for the intense humidity.
But there’s a second factor at work. At present, Australia’s climate is influenced by a positive Southern Annular Mode. This means the belt of intense westerly winds blowing across the Southern Ocean has been pushed further south, causing a ripple effect which can lead to more summer rain in Australia’s southeast, up to inland Queensland. This natural climate driver has meant easterly winds have blown uninterrupted from as far away as Fiji, carrying yet more humid air inland.
Many inland rivers in Queensland are in major flood (red triangles) as of April 1.Bureau of Meteorology, CC BY
These two streams of converging humid tropical air were driven up into the cooler heights of the atmosphere by upper and surface low pressure troughs, triggering torrential rain over wide areas of the outback
While these humid air masses have now dumped most of their water, more rain is coming in the aftermath of the short-lived Cyclone Dianne off northwest Australia. These rains won’t be as intense but may drive more flood peaks over already saturated catchments.
This is why it has been so wet in what is normally an exceptionally dry part of Australia.
What is this doing to the Channel Country?
Many Australians have never been to the remote Channel Country. It’s a striking landscape, marked by ancient, braided river channels.
Even for an area known for drought-flood cycles, the rainfall totals are extreme. This is a very rare event.
People who live there have to be resilient and self-sufficient. But farmers and graziers are bracing for awful losses of livestock. Livestock can drown in floodwaters, but a common fate is succumbing to pneumonia after spending too long in water. After the water moves down the channels, it will leave behind notoriously boggy and sticky mud. This can be lethal to livestock and native animals, which can find themselves unable to move.
Where will the water go next?
Little of these temporary inland seas will ever reach the ocean.
Some of the rain has fallen in the catchment of the Darling River, where it will flow down and meet the Murray. The Darling is often filled by summer rains, while the Murray gets more water from autumn and winter rains. This water will eventually reach the Southern Ocean.
But most of the rain fell further inland. The waters snaking through the channels will head south, flowing slowly along the flat ground for weeks until it crosses the South Australian border and begins to fill up Kati Thanda-Lake Eyre. Here, the waters will stop, more than 300 km from the nearest ocean at Port Augusta, and fill what is normally a huge, salty depression and Australia’s lowest point, 15 metres below sea level.
When Kati Thanda-Lake Eyre fills, it creates an extraordinary spectacle. Millions of brine shrimp will hatch from eggs in the dry soil. This sudden abundance will draw waterbirds in their millions, while fish carried in the floodwaters will spawn and eat the shrimp. Then there are the remarkable shield shrimps, hibernating inland crabs and salt-adapted hardyhead fish.
It’s rare that Kati Thanda-Lake Eyre fills up – but when it does, life comes to the desert.Mandy Creighton/Shutterstock
The rain event will send enough water to keep Lake Eyre full for many months and it usually takes up to two years for it to dry out again. We can expect to see a huge lake form – the size of a small European country. Birdwatchers and biologists will flock to the area to see the sight of a temporary sea in the desert.
Eventually, the intense sun of the outback will evaporate every last drop of the floodwaters, leaving behind salted ground and shrimp eggs for the next big rains.
As the climate keeps warming, we can expect to see more sudden torrential rain dumps like this one, followed by periods of rapid drying.
Steve Turton has previously received funding from the federal government.
New Zealand’s North Island features a number of geothermal systems, several of which are used to generate some 1,000 MegaWatts of electricity. But deeper down there may be even more potential.
Supercritical geothermal is hotter and deeper than conventional geothermal sources. It targets rocks between 375°C and 500°C, close to – but not within – magma.
Water at these temperatures and depths has three to seven times more energy for conversion to electricity, compared to ordinary geothermal generation at comparatively cooler temperatures of 200°C to 300°C.
The investment is staged, with $5 million earmarked for international consultants to design a super-deep well, and further funds to be released later for drilling to depths of up to six kilometres. Consultation is underway, with resources minister Shane Jones hoping to convince M?ori landowners to collaborate.
New Zealand already produces 1,000MW of electricity from conventional geothermal sources.Shutterstock/Chrispo
GNS Science estimates the central North Island might have about 3,500MW worth of this resource, although actually accessing it might be difficult and expensive. The energy consulting firm Castalia was engaged to predict how much would be worth developing, suggesting between 1,300MW and 2,000MW, starting from 2037.
This would be a lot of extra power. Even better, it would reduce the peaks and troughs in generation that arise from more variable solar and wind sources, which are expected to make up a growing share of electricity generation in the future. Supercritical geothermal is reportedly cost effective, which means the technology deserves serious consideration. But such claims should be subject to scrutiny.
But New Zealand has a healthy geothermal industry. In the past two decades, geothermal companies have invested $2 billion in hundreds of new wells and new power plants. The industry already knows how to drill wells and profit from them. So why is the government stepping in now?
In practice, supercritical geothermal exploration and development faces several research, technical and economic risks. Private enterprise seems unwilling to bear them alone, prompting the government to step in to establish feasibility.
How to crack soft rock
One problem supercritical geothermal might encounter is that drilling deeper might find lots of hot rock, but not much water. Drilling experiments in Japan and Italy have shown that reaching 500°C is possible, but in both cases the rock was so ductile (pliable and easily stretched) because of the high temperatures that it couldn’t keep open the gaps needed for water to flow.
However, the experience was different in Iceland where two wells managed to find water above 400°C. At this stage, it’s not clear whether this is because Iceland has special rocks – particularly basalts, which are less ductile – or because the country is being stretched through tectonic forces at a high rate. New Zealand is less able to count on basalts but it does experience rapid tectonic stretching.
Deep drilling would test this key hypothesis: is there permeability (gaps for water to flow through) at supercritical conditions? The only way to know for sure is to drill down.
If there isn’t permeability, the government could either abandon the investment or look into methods to create it. Multi-stage hydraulic fracturing (“fracking”) is an option which has worked overseas in the North American shale gas industry. It has also recently been demonstrated in some US geothermal systems.
Even if we did find permeability, the water produced in Iceland’s supercritical wells was enormously corrosive. A better option then might be to inject cold water into the well, suppressing the corrosive fluids. The injected water would heat up and rise into the overlying geothermal system – flushing the heat upwards.
However, both water injection and fracking can trigger earthquakes, perhaps a magnitude 4-5 every year or a magnitude 5-6 every few decades. This happened in 2017 in Pohang in South Korea where water injection triggered a magnitude 5.5 earthquake. It resulted in the cancellation of the geothermal project.
But there are many other geothermal projects where injection has not led to concerning earthquake activity.
Fierce competition from solar, wind and batteries
The other risk is economic. Supercritical geothermal might one day be technically feasible, but its potential contribution in New Zealand will be limited if it can’t beat other generation technologies on cost.
Worldwide, the renewable energy sector continues to be disrupted by unprecedented cost decreases driven by innovations in utility-scale battery storage and solar photovoltaics.
But the supply chains are largely overseas, mostly concentrated in China. This adds geopolitical complexity to the energy security calculus. Homegrown solutions are a strength.
Nevertheless, the International Renewable Energy Agency reports cost reductions for solar and battery modules of 89% and 86% between 2010 and 2023. Solar costs drop 33% each time the built amount doubles. Drops in battery cost are enabling large deployments for daily smoothing of the peaks and troughs of intermittent solar and wind generation.
This shifting cost landscape creates financial uncertainty for energy investors. While cost declines might not continue forever, it’s hard to pick when they will level off. Meanwhile, geothermal costs have been flat for a long time. A billion-dollar geothermal investment might quickly become uncompetitive.
Despite all these caveats, we shouldn’t overlook the positive signal of the government taking a bet on New Zealand science and innovation. It will be exciting to see what’s happening at six kilometres of depth underground. And although the plan is not to drill for magma, an accidental strike (as happened in Iceland) would lead to some amazing science.
Lastly, energy security deserves to be taken seriously over the long term. While supercritical geothermal won’t fix our immediate vulnerability to winter scarcity, it could help avoid similar issues in the 2040s.
David Dempsey receives science funding from MBIE for research into geothermal energy.
The north Queensland city of Townsville would “almost certainly” surpass its annual rainfall record this week, just three months into 2025, according to the Bureau of Meteorology’s senior meteorologist, Jonathan How.
In the dusty Queensland channel country, those old enough to remember still talk about the 1974 outback floods. For more than 50 years that has been the ultimate measuring stick for every downpour or trickle to flow through the central desert towards Kati Thanda-Lake Eyre.
On Sunday, in the tiny town of Jundah, in the heart of Queensland’s outback, the flood waters in some places measured 50cm higher than in 1974. Most of the town (including the pub) is still inundated. Surrounding towns are cut-off and could be isolated for weeks.
Anthony Albanese has confirmed the federal environmental protection agency he has promised to establish if elected would not be “the same model” as the one he promised but failed to legislate during this term of government.
In his first public comments about reviving the nature watchdog plan, Albanese confirmed Labor would pursue a different model in consultation with the states, industry and environmental groups.
The operators of Cadia goldmine have been ordered to pay $350,000 in fines and convicted of three offences after a prosecution by the New South Wales Environmental Protection Authority.
Cadia Holdings Limited, trading as Cadia Valley Operations, pleaded guilty to three offences under the environmental protection act relating to breaches of clean air regulations at the mine in central west NSW.
The thylacine might walk again. Or Lake Pedder might rise again. The possibility of ecological restoration in the island state plays into the appeal of going back in time
There is something about Tasmania that makes it a place where people want to restore the past, and not just because Tasmanians still regularly report seeing thylacines bounding off into the forest.
Certainly, it’s a retro kind of place. The landed gentry are still a thing, the powerful families of modern Tasmania tracing their ancestry back to the original squatters, who either took the land by force or bought it from the colonial government, no questions asked. Georgian mansions scatter the rural landscape; in Hobart, convict hewn stone is a building material of choice. Nearly 70% of Tasmanians had both parents born in Australia (the overall figure for the country is 47%), and more than 80% identify with a white ancestry (65% for Australia as a whole). If you ignore the giant cruise ships, the Teslas and the puffer jackets, you could imagine yourself in mid-century Australia.
