Water flows in mainland Australia’s most important river system, the Murray-Darling Basin, have been declining for the past 50 years. The trend has largely been blamed on water extraction, but our new research shows another factor is also at play.

We investigated why the Darling River, in the northern part of the basin, has experienced devastating periods of low flow, or no flow, since the 1990s. We found it was due to a decrease in rainfall in late autumn, caused by climate change.

The research reveals how climate change is already affecting river flows in the basin, even before water is extracted for farm irrigation and other human uses.

Less rain will fall in the Darling River catchment as climate change worsens. This fact must be central to decisions about how much water can be taken from this vital natural system.

A quick history of the Darling

The Darling River runs from the town of Bourke in northwest New South Wales, south to the Murray River in Victoria. Together, the two rivers form the Murray-Darling river system.

The Indigenous name for the Darling River is the Baaka. For at least 30,000 years the river has been an Indigenous water resource. On the river near Wilcannia, remnants of fish traps and weirs built by Indigenous people can still be found today.

The Darling River was a major transport route from the late 19th to the early 20th century.

In recent decades, the agriculture industry has extracted substantial quantities of water from the Darling’s upstream tributaries, to irrigate crops and replenish farm dams. Water has also been extracted from Menindee Lakes, downstream in the Darling, to benefit the environment and supply the regional city of Broken Hill.

A river in trouble

Natural weather variability means water levels in the Darling River have always been irregular, even before climate change began to be felt.

In recent years, however, water flows have become even more irregular. This has caused myriad environmental problems.

At Menindee Lakes, for example, fish have died en masse – incidents experts say is ultimately due to a lack of water in the river system.

Periods of heavy rain in recent years have dramatically improved water flows.

But in between those episodes, water levels and quality have declined, due to factors such as droughts, expanded water extraction, salinity and pollution from farms.

Compounding the droughts, smaller flows that once replenished the system have now greatly reduced. Our research sought to determine why.

What we found

We examined rainfall and water flows in the Darling River from 1972 until July 2024. This includes from the 1990s – a period when global warming accelerated.

We found a striking lack of short rainfall periods in April and May in the Darling River from the 1990s. The reduced rainfall led to long periods of very low, or no flow, in the river.

Since the 1990s under climate change, shifts in atmospheric circulation have generated fewer rain-producing systems. This has led to less rain in inland southeast Australia in autumn.

The river system particularly needs rainfall in the late autumn months, to replenish rivers after summer.

The periods of little rain were often followed by extreme floods. This is a problem because the rain fell on dry soils and soaked in, rather than running into the river. This reduced the amount of water available for the environment and human uses.

In addition to the fall in autumn rainfall, we found the number of extreme annual rainfall totals for all seasons has also fallen since the 1990s.

We also examined monthly river heights at Bourke, Wilcannia and Menindee. We found periods of both high and low water levels before the mid-1990s. But the low water levels at all three locations from 2000 onwards were the lowest in the period.

Ensuring water for all

Australia is the driest inhabited continent on Earth. Ensuring steady water supplies for human use has always been challenging.

Falls in Darling River water levels in recent decades have largely been attributed to water extraction for farm dams, irrigation and town use.

But as our research shows, the lack of rainfall in the river catchment – as a result of climate change – is also significant. The problem will worsen as climate change accelerates.

This creates a huge policy challenge. As others have noted, the Murray-Darling Basin Plan does not properly address climate change when determining how much water can be taken by towns and farmers.

Both the environment and people will benefit from ensuring the rivers of the basin maintain healthy flows into the future. As our research indicates, this will require decision-makers to consider and adapt to climate change.

Milton Speer, Visiting Fellow, School of Mathematical and Physical Sciences, University of Technology Sydney and Lance M Leslie, Professor, School of Mathematical And Physical Sciences, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

When dead animals are left lying around in nature, who takes advantage of the free feed – carnivores or herbivores? The answer may surprise you.

In Australia, people tend to think carnivores – such as dingoes, ravens, foxes and wedge-tailed eagles – lead the clean-up crew.

But our new research shows common brushtail possums – often thought to be herbivores – also dine on animal carcasses.

Understanding when and where brushtail possums scavenge is important. It can improve our knowledge of how carcasses are disposed of in nature, and how nutrients cycle through ecosystems.

Seeking a nutritious meal

Scavenging may provide specific essential nutrients otherwise lacking in herbivore diets.

Carcasses often contain much greater levels of crude protein than leafy greens do. Similarly, chewing on bones, may increase the intake of calcium and phosphorus, two key minerals essential for growth.

Scavenging on carrion may also help herbivores meet nutritional requirements in regions where typical food resources may be restricted during some seasons. Similarly, in times of drought, thirst may also drive herbivores to scavenge in an attempt to extract fluids from carcasses.

Though it may seem gruesome, scavenging is crucial to healthy ecosystems. Clearing carcasses from the landscape by feeding them back into food chains recycles nutrients into living systems.

Our previous research has found native marsupial herbivores feasting on the dead.

In alpine Australia, possums accounted for 61% of all recorded carcass scavenging – a proportion far surpassing species more typically considered carcass consumers.

In our latest research, we wanted to understand the factors that influence carrion consumption by brushtail possums in different ecosystems.

What we did

We monitored fresh eastern grey kangaroo carcasses across both alpine (Kosciuszko National Park) and temperate (Wolgan Valley, Greater Blue Mountains National Park) regions in New South Wales. We also compared sites in both open (grassland with no canopy cover) and closed (woodland) habitats, in cool and warm seasons.

At each carcass, we used a remote camera “trap” to record scavenging behaviours.

We found possums were one of the main scavengers, often feeding from carrion more than typical scavengers such as dingoes and ravens.

Possum scavenging rates varied by habitat and season. Regardless of region, possums scavenged exclusively in closed canopy habitats under the trees, probably for protection from predators and other scavengers such as dingoes, red foxes, and wedge-tailed eagles.

Out in the cold

Possum scavenging activity varied according to the season.

In temperate regions, possums scavenged only in winter when other food resources were limited.

In alpine areas, where food is scarce even in summer, possums scavenged year-round. But they still ate more from carcasses in cooler months. This may be necessary for possums to get the nutrition they need when other normal food resources — such as leaves, flowers and fruit — are limited.

Competition between scavengers may also change with the seasons. For example, in alpine regions, we saw fewer large scavengers such as dingoes in winter, possibly reducing competition and making it easier for possums to access carrion.

During warmer months, insect activity increases. These tiny scavengers often start eating a carcass within minutes of its death, accelerating its decomposition. It means animals such as possums have less time to feed on the carrion.

Flexible ‘herbivores’ around the world

Previous research has shown many herbivore diets are more flexible than previously thought. All over the world, certain plant-eaters have been found scavenging on animal remains – especially when other food sources are limited, such as during drought or after fire.

In Africa, hippopotamuses were found to have consumed flesh from the carcasses of other animals. In the United States, white-tailed deer fed on discarded fish.

Similarly, on a small island off Cape Town, introduced European fallow deer ate dead rabbits. On the Eurasian tundra (treeless plains), reindeer devoured lemming carcasses. In Italy, crested porcupine ate dead pigeons.

These are all still primarily herbivorous animals, they just happen to dip into carcass resources when they need to.

Improving our understanding of ‘bloody hungry’ herbivores

Our study found brushtail possums are an important scavenging species across several Australian ecosystems. It also highlights how scavenging can vary with a region, season and habitat.

Understanding the unusual foraging behaviour of the common brushtail possum could also help inform more effective wildlife management. Specifically, understanding how carcasses can support possum populations during cooler months in places like New Zealand, where they are considered an invasive pest, may lead to more effective control measures.

Our methods could also help scientists understand herbivore scavenging in other environments. This may provide valuable insights into complexities of food webs and how nutrients move through ecosystems.

Patrick Finnerty, Postdoctoral research fellow in conservation, University of Sydney and Thomas Newsome, Associate Professor in Global Ecology, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Over the last decade, several groups in Australia have successfully mobilised against fossil fuel interests. But which ones have gone the distance?

The urgent global threat of climate change might suggest groups running large-scale campaigns are the ones likely achieve lasting change. But my research suggests groups focused on local efforts are often more successful.

I’ve studied coalitions and campaigns, the climate movement and people-power globally. I’ve found groups with strong local roots can evolve and endure better than larger, more dispersed groups.

The trajectory of two major environmental groups in Australia demonstrate the point.

The first is focused around the Northern Rivers in New South Wales. There, the threat of gas extraction in the 2010s prompted the community to start organising through the national anti-gas group Lock the Gate. When floods struck the region in 2017 and 2022, many organisers shifted focus to form a new, successful alliance.

The second is the Stop Adani group. Organising began around 2010 after plans for the giant Adani coal mine in central Queensland were announced. The group successfully reduced the size of the proposed mine, but energy behind the movement dwindled.

Examining the way these groups organised and operated – and how long they lasted – offers lessons for others.

Northern Rivers

The Northern Rivers region has attracted environmentally-minded people from the 1960s peace movement onward. This activist history was almost certainly not considered by gas companies when they began planning large-scale fracking operations.

Locals began meeting under the banner “Lock the Gate”. In 2014, they launched the Bentley Blockade camp-in on land earmarked for gas extraction. The campaign worked and the Northern Rivers remains gasfield-free.

When unprecedented floods hit in 2017 and 2022, locals involved in Lock the Gate shifted focus. They formed the Northern Rivers Community Resilience Alliance to work on mutual aid and ongoing resilience.

Stop Adani

In 2010, the multinational Adani Group announced plans for the Carmichael coal mine in Queensland’s Galilee Basin. Climate groups around the country were outraged.

People began campaigning against the mine, initially locally focused on the coal port. By 2017 the campaign became national under the banner Stop Adani.

By 2017, Stop Adani had built a national strategy coordinating more than 100 community groups across many cities and regions. The movement used public pressure to slow progress. It reduced but did not stop the mine, which began exporting coal in late 2021.

Who was in these groups?

To tackle the gasfield threat, Northern Rivers residents doorknocked neighbours and local councils voted to declare their region gasfield free. Lock the Gate organisers deliberately set out to make their group as representative as possible.

Disagreements were inevitable. Farmers worried about the effect of gasfields on groundwater while environmentalists focused on the climate. But their relationships in the same place helped maintain unity. This broad base also meant opponents couldn’t write them off as “angry greenies”. As organiser Annie Kia has said, the movement “maximised self-organisation”.

By contrast, my analysis and interviews have shown Stop Adani involved local groups mostly comprised of white, middle class, well-educated urban women from the east coast. This made it easier to find agreement. But individual groups were smaller and less diverse than the Northern Rivers group.

Who designed the strategy?

Northern Rivers organisers tapped experienced campaigners to create the strategy. This helped overcome tensions within the broad coalition and arguably drove more creativity.

The Stop Adani strategy was done nationally. Community groups were invited to plan coordinated local actions. The led to effective public pressure on banks financing the mine, and other organisations.

But national-local separation comes at a cost, as my research has found. Local groups tasked with carrying out a national plan and had less ability to build their own plans.

Framing matters

Both groups focused on stopping fossil fuel extraction, but their framing differed.

Northern Rivers residents were motivated by a range of concerns, from avoiding damage to water tables to tackling climate change. To harness these motivations, the group framed their demand positively – fighting for a gasfield-free Northern Rivers region.

Stop Adani was built on a simple negative: stop the mine. This drove urgency and led to high levels of participation. But it also prompted a backlash, such as tense stand-offs between Central Queensland residents and a convoy organised by Bob Brown against the mine in 2019.

The stark framing created a challenge in negotiating with government. But success is not always black or white. State and federal governments slashed the size of the mine to just one-sixth the size of the original plans.

The negative framing also made it hard to retain participants. When years of protests failed to stop the mine, mass participation fell away.

But Stop Adani didn’t give up. In recent years, Traditional Owners have kept up the pressure on the mine’s financial and political backers.

What does success look like?

Stop Adani and Northern Rivers had very similar goals: stop the mine, stop the gasfields. By this metric, both groups were largely successful.

But Northern Rivers organisers also focused on building a broad movement beyond the usual environmentally-minded people. That’s why the group is still going strong, even after gas plans were defeated.

This is a remarkable community asset. When much of Lismore went underwater in 2022, state and federal help was slow. So community groups sprang into action, pooling resources and cooperating during the immediate emergency and the long clean-up.

Other communities now look to the Northern Rivers as a model of ground-up disaster recovery.

Their success should give us hope. As the climate warps, groups with strong community roots are well-placed to lead the response to the changing demands of the climate crisis.

Amanda Tattersall, Associate Professor in Urban Geography and Host of ChangeMakers Podcast, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The rise of artificial intelligence (AI) has triggered concern about potentially detrimental effects on humans. However, the technology also has the potential to harm animals.

An important policy reform now underway in Australia offers an opportunity to address this. The federal government has committed A$5 million to renewing the lapsed Australian Animal Welfare Strategy. Consultation has begun, and the final strategy is expected in 2027.

While AI is not an explicit focus of the review, it should be.

Australians care about animals. The strategy could help ensure decision-makers protect animals from AI’s harms in our homes, on farms and in the wild.

Will AI harms to animals go unchecked?

Computers are now so developed they can perform some complex tasks as well as, or better than, humans. In other words, they have developed a degree of “artificial intelligence”.

The technology is exciting but also risky.

Warnings about the risks to humans include everything from privacy concerns to the collapse of human civilisation.

Policy-makers in the European Union, the United States and Australia are scrambling to address these issues and ensure AI is safe and used responsibly. But the focus of these policies is to protect humans.

Now, Australia has a chance to protect animals from AI.

Australia’s previous Animal Welfare Strategy expired in 2014. It’s now being revived, and aims to provide a national approach to animal welfare.

So far, documents released as part of the review suggest AI is not being considered under the strategy. That is a serious omission, for reasons we outline below.

Powerful and pervasive technology in use

Much AI use benefits animals, such as in veterinary medicine. For example, it may soon help your vet read X-rays of your animal companion.

AI is being developed to detect pain in cats and dogs. This might help if the technology is accurate, but could cause harm if it’s inaccurate by either over-reporting pain or failing to detect discomfort.

AI may also allow humans to decipher animal communication and better understand animals’ point of view, such as interpreting whale song.

It has also been used to discover which trees and artificial structures are best for birds.

But when it comes to animals, research suggests AI may also be used to harm them.

For example, it may be used by poachers and illegal wildlife traders to track and kill or capture endangered species. And AI-powered algorithms used by social media platforms can connect crime gangs to customers, perpetuating the illegal wildlife trade.

AI is known to produce racial, gender and other biases in relation to humans. It can also produce biased information and opinions about animals.

For example, AI chatbots may perpetuate negative attitudes about animals in their training data – perhaps suggesting their purpose is to be hunted or eaten.

There are plans to use AI to distinguish cats from native species and then kill the cats. Yet, AI image recognition tools have not been sufficiently trained to accurately identify many wild species. They are biased towards North American species, because that is where the bulk of the data and training comes from.

Algorithms using AI tend to promote more salacious content, so they are likely to also recommend animal cruelty videos on various platforms. For example, YouTube contains content involving horrific animal abuse.

Some AI technologies are used in harmful animal experiments. Elon Musk’s brain implant company Neuralink, for instance, was accused of rushing experiments that harmed and killed monkeys.

Researchers warn AI could estrange humans from animals and cause us to care less about them. Imagine AI farms almost entirely run by smart systems that “look after” the animals. This would reduce opportunities for humans to notice and respond to animal needs.

Existing regulatory frameworks are inadequate

Australia’s animal welfare laws are already flawed and fail to address existing harms. They allow some animals to be confined to very small spaces, such as chickens in battery cages or pigs in sow stalls and farrowing crates. Painful procedures (such as mulesing, tail docking and beak trimming) can be legally performed without pain relief.

Only widespread community outrage forces governments to end the most controversial practices, such as the export of live sheep by sea.

This has implications for the development and use of artificial intelligence. Reform is needed to ensure AI does not amplify these existing animal harms, or contribute to new ones.

Internationally, some governments are responding to the need for reform.

The United Kingdom’s online safety laws now require social media platforms to proactively monitor and remove illegal animal cruelty content from their platforms. In Brazil, Meta (the owner of Facebook and WhatsApp) was recently fined for not taking down posts that had been tagged as illegal wildlife trading.

The EU’s new AI Act also takes a small step towards recognising how the technology affects the environment we share with other animals.

Among other aims, the law encourages the AI industry to track and minimise the carbon and other environmental impact of AI systems. This would benefit animal as well as human health.

The current refresh of the Australian Animal Welfare Strategy, jointly led by federal, state and territory governments, gives us a chance to respond to the AI threat. It should be updated to consider how AI affects animal interests.

Lev Bromberg, PhD Candidate and Research Fellow, The University of Melbourne; Christine Parker, Professor of Law, The University of Melbourne, and Simon Coghlan, Senior Lecturer in Digital Ethics, Centre for AI and Digital Ethics, School of Computing and Information Systems, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

In a race against time, scientists are exploring new ways to restore natural systems. Alongside traditional methods such as planting trees, reducing pollution and reintroducing native species, a surprising new tool is emerging: sound. Ecologists can harness sound to bring life back to degraded ecosystems.

On land and at sea, natural soundscapes are being replicated to stimulate growth, reproduction and even communication among species. Sound is already being used to restore oyster beds and coral reefs.

In our new research, we found beneficial plant microbes are also receptive to sound. We used high-frequency white noise to stimulate a fungus that promotes plant growth. The noise is a bit like the sound emitted in between channels of an old-fashioned radio.

This adds a new dimension to restoration projects. Imagine using tailored soundscapes to restore wetlands, forests or grasslands, simply by artificially amplifying the sonic cues that attract wildlife, stimulate growth and rebuild relationships between species. We see a bright future for this “biodiversity jukebox”, with tracks for every ecosystem.

Sound as an ecological tool

In healthy ecosystems, everything from animal calls to water trickling underground creates a sonic landscape or “soundscape” that ultimately supports biodiversity.

Conversely, the soundscapes in degraded ecosystems are often diminished or altered. This can change the way species behave and ecosystems function.

Marine biologists were among the first to explore sound as a tool for restoring Australia’s southern oyster reefs. Intact oyster reefs provide habitat for many species and prevent shoreline erosion. But pollution, overharvesting and dredging almost wiped them out more than a century ago.

It turns out playing sounds of healthy reefs, namely snapping shrimp, underwater encourages baby oysters to settle and grow. These sounds mimic the natural environment of thriving oyster beds.

The results have been impressive. Oyster populations show signs of recovery in areas where soundscapes have been artificially restored.

Similarly, fish support healthy coral reefs by grazing on algae that can otherwise smother corals. Playing the sounds of healthy coral reefs can attract young fish to degraded reefs. This helps kickstart reef recovery.

The power of sound in plant microbiology

Building on these successes, we ventured into new territory. In our new research we used sound to stimulate the growth of soil microbes.

These microbes play an essential role in plant health. Some promote nutrient uptake in plants, others protect against disease. But these communities of microorganisms can be diminished and disrupted in degraded soils, hampering plant growth and ecosystem recovery.

We wanted to find out whether specific sounds could encourage the growth of these beneficial microbes. We ran a series of experiments, to test the effect of sound on the growth and reproduction rate of a particular fungus known to stimulate plant growth and protect against diseases.

We grew the fungus in the laboratory in 40 Petri dishes and subjected half of them to treatment with sound. We played a sound recording similar to the high-frequency buzz of white noise for 30 minutes a day over five days. Then we compared the amount of fungal growth and the number of spores between the two groups.

In technical terms, the frequency was 8 kHz and level was 80 dB, which is quite loud, like the sound of a busy city street or vacuum cleaner, almost loud enough to damage hearing.

We used a monotonous sound for experimental reasons, because it is easy to control. But a more natural or diverse soundscape may be even better. We plan to do more research on this in the near future.

We found sound stimulated the fungi, increasing the growth rate by more than seven times and the production of spores by more than four times compared to the control (no sound).

Why sound works

Why does sound have such a powerful effect on ecosystems? The answer lies in the way organisms interact with their environment.

Sound travels almost five times faster in water than in air, making it an efficient means of communication for marine life such as oysters, fish and whales.

Trees detect the soundwaves produced by running water, and their roots move towards the vibration.

We already know sound influences the activity of microbes. We think it stimulates special receptors on the membranes of the microbes. These receptors might trigger a response in the cells, such as switching genes responsible for growth on or off.

Is sound the future of restoration?

Microbes support plant life, help maintain soil structure, hold water and store carbon. By stimulating beneficial microbes with sound, we may be able to improve large-scale restoration projects. This approach may also support regenerative agriculture, where farming works with nature rather than against it.

Our next steps include refining the sound patterns that are most effective in different ecosystems. We then need to scale up our research to test different sounds in diverse environments. We envisage creating a “biodiversity jukebox” of beneficial sounds to enhance ecosystem health.

It’s clear what we hear – and don’t hear – profoundly influences the environment. So we’re also interested in noise cancellation. By this, we mean barriers to protect ecosystems from potentially undesirable noises. For instance, we’re asking questions such as: do traffic and industrial noises harm the ecosystem?

As ecosystems face increasing pressure from climate change, biodiversity loss and habitat destruction, sound can become a powerful tool for restoration.

While the science is still in its infancy, it has huge potential.

Ultimately, sound-based restoration might offer a low-impact and cost-effective approach to help ecosystems recover. The future of restoration could be as much about what we hear as what we see.

Jake M Robinson, Ecologist and Researcher, Flinders University and Martin Breed, Associate Professor in Biology, Flinders University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Pollution and waste, climate change and biodiversity loss are creating a triple planetary crisis. In response, UN Environment Programme executive director Inger Andersen has called for waste to be redefined as a valuable resource instead of a problem. That’s what urban mining does.

We commonly think of mining as drilling or digging into the earth to extract precious resources. Urban mining recovers these materials from waste. It can come from buildings, infrastructure and obsolete products.

An urban mine, then, is the stock of precious metals or materials in the waste cities produce. In particular, electronic waste, or e‑waste, has higher concentrations of precious metals than many mined ores. Yet the UN Global E‑waste Monitor estimates US$62 billion worth of recoverable resources was discarded as e‑waste in 2022.

Urban mining can recover these “hidden” resources in cities around the world. It offers sustainable solutions to the problems of resource scarcity and waste management. And it happens in the very cities that are centres of overconsumption and hotspots for the greenhouse gas emissions driving climate change.

What sort of waste can be mined?

Materials such as concrete, pipes, bricks, roofing materials, reinforcements and e‑waste can be recovered for reuse. Urban waste can be “mined” for metals such as gold, steel, copper, zinc, aluminium, cobalt and lithium, as well as glass and plastic. Mechanical or chemical treatments are used to retrieve these metals and materials.

Simply disposing of this waste has high financial and environmental costs. In Australia, about 10% of waste is hazardous. Landfill costs are soaring as cities run out of space to discard their waste.

The extent of this fast-growing problem is driving the growth of urban mining around the world. We are then salvaging materials whose supply is finite, while reducing the impacts of waste disposal.

What’s happening globally?

In Europe, the focus is largely on construction and demolition waste. Europe produces 450 million to 500 million tonnes of this waste each year – more than a third of all the region’s waste. Through its urban mining strategy, the European Commission aims to increase the recovery of non-hazardous construction and demolition waste to at least 70% across member countries by 2030.

In Asia, urban mining has focused on e‑waste. However, the region recovers only about 12% of its e‑waste stock. Rates of e‑waste recycling vary greatly: 20% for East Asia, 1% for South Asia, and virtually zero for South-East Asia. China, Japan and South Korea are leading the way in Asia.

Australia is on the right track. Our recovery rate for construction and demolition materials climbed to 80% by 2022 — the highest among all types of waste streams. However, we recover only about a third of the value of materials in our e-waste.

Africa has also recognised the growing value of urban mining resources. Regional initiatives include the Nairobi Declaration on e‑waste, the Durban Declaration on e‑Waste Management in Africa and the Abuja Platform on e‑Waste.

Urban mining solves many problems

The OECD forecasts that global materials demand will almost double from 89 billion tonnes in 2019 to 167 billion tonnes in 2060. The United Nations’ Global Waste Management Outlook 2024 shows the amount of waste and costs of managing it are soaring too. It’s estimated the world will have 82 million tonnes of e‑waste to deal with by 2030.

These trends mean urban mining is becoming ever more relevant and important.

Urban mining also helps cut greenhouse gas emissions. Unlocking resources near where they are needed reduces transport costs and emissions. Urban mining also provides resource independence and creates employment.

In addition, increasing recovery and recycling rates reduce the pressure on finite natural resources.

Urban mining underpins circular economy alternatives such as the “deposit and return” schemes that give people financial incentives to return e‑waste and containers for recycling in cities such as Singapore, Sydney, Darwin and San Francisco. By 2030, San Francisco aims to halve disposal to landfill or incineration and cut solid waste generation by 15%.

What more needs to be done?

Governments have a role to play by adopting and enforcing policies, laws and regulations that encourage recycling through urban mining instead of sending waste to landfill. European Union laws, for example, mandate increased recycling targets for municipal waste overall and for packaging waste, including 80% for ferrous metals and 60% for aluminium.

In Australia, 2019 legislation prohibits landfills from accepting anything with a plug, battery or cord. Anything with a plug is designated as e-waste.

Product design is an important consideration. A designer must balance a product’s efficiency with making it easy to recycle. Products with greater efficiency and easy-to-recycle parts are more likely to use less energy, lead to less waste and hence less natural resource extraction.

Our urban mining research documents a more sustainable approach to product design. Increasing product stewardship initiatives are expected to encourage better product design and standards that promote reuse and recycling, producer responsibility and changes in consumer behaviour.

Good information about the available resources is essential too. The Urban Mine Platform, ProSUM and Waste and Resource Recovery Data Hub collect data on e‑waste, end-of-life vehicles, batteries and building and mining waste. These centralised databases allow easy access to data on the sources, stocks, flows and treatment of waste.

Traditional mining is not the only method for extracting raw materials for the green transition. Waste is set to be increasingly recycled, reducing demand for virgin materials. A truly circular economy can become a reality if governments develop and apply an urban mining agenda.

Michael Odei Erdiaw-Kwasie, Lecturer in Sustainability| Business and Accounting Discipline, Charles Darwin University; Matthew Abunyewah, Research Fellow, The Australasian Centre for Resilience Implementation for Sustainable Communities, Charles Darwin University, and Patrick Brandful Cobbinah, Associate Professor of Urban Planning, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Evidence is mounting that modern medicines present a growing threat to ecosystems around the world. The chemicals humans ingest to stay healthy are harming fish and other animals.

Modern pharmaceuticals have revolutionised disease prevention and treatment. But after our bodies use medicines, they excrete them. Eventually, the chemicals can end up in rivers, oceans and soils.

This is a problem, because medicines designed to treat humans can also affect other species in serious ways, changing their bodies and behaviour. The chemicals can also pass through food webs and affect animals higher up the chain.

Urgent action is needed to design drugs that work on humans, but don’t harm nature.

Evidence of harm

In the past two decades, studies have emerged showing the extent to which medicines persist in nature.

In August this year, Australian researchers found the antidepressant fluoxetine – sold under the brand name Prozac, among others – can harm male guppies in ways that affected their body condition and breeding.

Research in 2022 examined pharmaceuticals in rivers in 104 countries of all continents. It found pharmaceutical contaminants posed a threat to the health of the environment or humans in more than a quarter of locations studied.

In 2018, a study of watercourses and surrounds in Melbourne found more than 60 pharmaceutical compounds in aquatic invertebrates and spiders.

Researchers in the United States have found hormones in the contraceptive pill have caused male fish to produce a protein usually produced by female fish. This “feminisation” led to collapses in fish populations.

And a psychoactive drug found in wastewater effluent has been found to alter wild fish behaviour and feeding.

Benign by design

So how do we solve this problem?

More effective and economical wastewater treatments must be developed to remove pharmaceuticals from wastewater before it is discharged into the environment.

In addition, researchers developing pharmaceuticals must adopt a “benign by design” approach across the entire life of a drug.

From the outset, drugs must be designed to decompose quickly and fully after being excreted by humans. It’s possible for drug scientists to alter the chemical and physical properties of drugs so after humans excrete them, the active ingredients mineralise, or change form, to base substances such as carbon dioxide and water.

Traditionally researchers have designed drugs not to break down, either on the shelf or in the human body. While these properties remain important, drug developers should ensure medicines degrade quickly once in the environment.

Taking action

The principles of sustainable drug discovery should be included in Australia’s academic curriculum.

This would hopefully produce a generation of drug researchers who prioritise, where possible, medications that don’t harm the environment.

Regulation is also needed to ensure “greener” drug development. The International Pharmaceutical Federation last year took steps in this direction. The global body, representing more than 4 million pharmacists and pharmaceutical scientists, released a statement calling for all medicines to be rigorously tested for environmental risk.

The European Medicines agency has gone even further. It requires the environmental risk of a medicine to be assessed before it’s approved for use.

The assessment considers a medicine’s chemical properties, potential ecological harm and where in the environment it may end up, such as water or soil. Pharmaceutical companies are also required to produce waste management plans that minimise environmental impact.

Research has found Australia lags behind on introducing similar requirements for environmental risk assessments for medicines.

By prioritising eco-friendly practices, the pharmaceutical sector can contribute to a healthier planet, while continuing to provide safe and effective medicines.

Everyday Australians can also take action to reduce environmental pollution from medicines. The federal government’s Return Unwanted Medicines project allows household drugs to be returned to pharmacies for safe and correct disposal.

By dropping off old medicines to your local chemist – instead of flushing or throwing them away, as some people mistakenly do – you can help look after fish and other wildlife in your area.

Lauren T. May, Senior Lecturer and Group Leader, Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University and Manuela Jorg, Research Fellow & Lab Head in Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A city street may seem an unusual place to save species found in critically endangered grasslands. My new research, though, shows we can use plants from these ecosystems to create beautiful and biodiverse urban wildflower meadows. This means cities, too, can support nature repair.

Species-rich grassy ecosystems are some of the most threatened plant communities on the planet. Occupying easily developed flat land, grassy ecosystems are routinely sacrificed as our cities expand.

In south-east Australia, the volcanic plains that support Melbourne’s northern and western suburbs were once grasslands strewn with wildflowers, “resembling a nobleman’s park on a gigantic scale”, according to early explorer Thomas Mitchell. But these exceptionally diverse, critically endangered ecosystems have been reduced to less than 1% of their original area. The few remnants continue to be lost to urban development and weed invasion.

Unfortunately, efforts to restore the grasslands around Melbourne have had mixed results. In 2020 the City of Melbourne took matters into its own hands. Recognising it is possible to enrich the diversity of birds, bats and insects by providing low-growing native plants, the council set a goal to increase understorey plants by 20% on the land it manages.

Creating a large native grassland in inner-city Royal Park would help achieve this goal. Adopting a technique used by wildflower meadow designers, we sowed a million seeds of more than two dozen species from endangered grasslands around Melbourne. All but one of these species established in the resulting native wildflower meadow.

What were the challenges at this site?

Existing restoration techniques remove nutrient-enriched topsoils full of weed seeds before sowing native seeds. The target plant community can then establish with less competition from nutrient-hungry weeds.

However, this approach could not be used at the Royal Park site. Topsoil removal cannot be used on many urban sites where soils are contaminated or there are underground services. Alternative approaches are needed to reduce weed competition while minimising soil disturbance.

I saw a possible answer in the horticultural approaches used to create designed wildflower meadows.

While still rare in Australia, designed wildflower meadows can increase the amenity and biodiversity of urban environments. They also reduce the costs of managing and mowing turf grass. These meadows are designed to be infrequently mown or burnt.

Wildflower meadow designers typically use an international suite of species that can be established from seed and persist without fertiliser or regular irrigation. An abundance of flowers makes people more accepting of “messy” vegetation. Recognising this, designers select a mix of species that will flower for as much of the year as possible.

To reduce competition from weeds, these meadows are often created on a layer of sand that covers the original site soils. The low-nutrient sand buries weed seeds and creates a sowing surface that resists weed invasion from the surrounding landscape.

However, the grasslands around Melbourne grow on clay soils, not sand. Would these techniques work for plants from these ecosystems?

A deep sand layer controls weeds and slugs

To find out we sowed more than a million seeds on sites with two depths of sand (10mm and 80mm) and one without a sand layer in Royal Park. Within one year, 26 of the 27 species sown had established to form a dense, flowering meadow across all sand depths. These plants included three threatened species.

Crucially, the deepest sand layer reduced weed numbers and therefore time spent weeding.

Interestingly, slugs played a role in determining the diversity of the native meadow. South-east Australia’s grasslands have largely evolved without slugs. As a result, seedlings lack chemical or physical defences against grazing by slugs, which can greatly reduce species diversity in native meadows.

Again, sand provided a real benefit. Fewer slugs occurred on the deepest sand layer compared to bare soil. The suggestion that sand can deter slugs is consistent with meadow research in Europe.

Now to repair nature in all our cities

Our research gives us another technique to reinstate critically endangered plant communities. We can use it to bring nature back to city parks and streets.

Working in urban contexts also unlocks other advantages. There’s ready access to irrigation while the meadow gets established and to communities keen to care for natural landscapes. Creating native wildflower meadows in cities also helps native animals survive, including threatened species that call our cities home.

People will be able to engage with beautiful native plants that are now rare in cities. Enriching our experience of nature can enhance our health and wellbeing.

My colleagues and I trialled these approaches with the support of the City of Melbourne. We are continuing our research to improve the scale and sustainability of native wildflower meadows in other municipalities.

Native wildflower meadows and grassland restoration projects could genuinely help Australia meet its commitment to restore 30% of degraded landscapes. But first we need to invest much more in seed production. Reinstating native species on degraded land requires a lot of seed.

Once seed supply is more certain, we will be able to bring back native biodiversity and beauty to streets, parks and reserves across the country.

I would like to acknowledge the Traditional Custodians of the land on which the project took place, the Wurundjeri and Bunurong people of the Kulin Nations, and we pay our respects to their Elders, past, present and emerging. I also acknowledge my colleagues listed as co-authors on the research paper that formed the basis of this article: urban ecologists Nicholas S.G. Williams and Stephen Livesley, and seed ecologists Megan Hirst and John Delpratt.

Katherine Horsfall, PhD Candidate, School of Agriculture, Food and Ecosystem Sciences, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Long-spined sea urchins have emerged as an environmental issue off Australia’s far south coast. Native to temperate waters around New South Wales, the urchins have expanded their range south as oceans warm. There, they devour kelp and invertebrates, leaving barren habitats in their wake.

Lobsters are widely accepted as sea urchins’ key predator. In efforts to control urchin numbers, scientists have been researching this predator-prey relationship. And the latest research by my colleagues and I, released today, delivered an unexpected result.

We set up several cameras outside a lobster den and placed sea urchins in it. We filmed at night for almost a month. When we checked the footage, most sea urchins had been eaten – not by lobsters, but by sharks.

This suggests sharks have been overlooked as predators of sea urchins in NSW. Importantly, sharks seem to very easily consume these large, spiky creatures – sometimes in just a few gulps! Our findings suggest the diversity of predators eating large sea urchins is broader than we thought – and that could prove to be good news for protecting our kelp forests.

A puzzling picture

The waters off Australia’s south-east are warming at almost four times the global average. This has allowed long-spined sea urchins (Centrostephanus rodgersii) to extend their range from NSW into waters off Victoria and Tasmania.

Sea urchins feed on kelp and in their march south, have reduced kelp cover. This has added to pressure on kelp forests, which face many threats.

Scientists have been looking for ways to combat the spread of sea urchins. Ensuring healthy populations of predators is one suggested solution.

Overseas research on different urchin species has focused on predators such as lobsters and large fish. It found kelp cover can be improved by protecting or reinstating these predators.

In NSW, eastern rock lobsters are thought to be important urchin predators. The species has been over-fished in the past but stocks have significantly bounced back in recent years.

But despite this, no meaningful reduction in urchin populations, or increase in kelp growth, has been observed in NSW.

Why not? Could it be that lobsters are not eating urchins in great numbers after all? Certainly, there is little empirical evidence on how often predators eat urchins in the wild.

What’s more, recent research in NSW suggested the influence of lobsters on urchin populations was low, while fish could be more important.

Our project aimed to investigate the situation further.

What we did

We tied 100 urchins to blocks outside a lobster den off in Wollongong for 25 nights. This tethering meant the urchins were easily available to predators and stayed within view of our cameras.

Then we set multiple cameras to remotely turn on at sunset and turn after sunrise each day, to capture nocturnal feeding. We used a red-filtered light to film the experiments because invertebrates don’t like the white light spectrum.

We expected our cameras would capture lobsters eating the urchins. But in fact, the lobsters showed little interest in the urchins and ate just 4% of them. They were often filmed walking straight past urchins in search of other food.

Sharks, however, were very interested in the urchins. Both crested horn sharks (Heterodontus galeatus) and Port Jackson sharks (H. portusjacksonii) entered the den and ate 45% of the urchins.

As the footage below shows, sharks readily handled very large urchins (wider then 12 centimetres) with no hesitation.

Until now, it was thought few or no predators could handle urchins of this size. Larger urchins have longer spines, thicker shells and attach more strongly to the seafloor, making them harder to eat.

But the sharks attacked urchins from their spiny side, showing little regard for their sharp defences. This approach differs from other predators, such as lobsters and wrasses, which often turn urchins over and attack them methodically from their more vulnerable underside.

In fact, some sharks were so eager to eat urchins, they started feeding before the cameras turned on at sunset. This meant we had to film by hand.

A complex food web

Our experiment showed the effect of lobsters on urchins in the wild is less than previously thought. This may explain why efforts to encourage lobster numbers have not helped control urchin numbers.

We also revealed a little-considered urchin predator: sharks.

Lobsters are capable but hesitant predators, whereas sharks seem eager to eat urchins. And crested horn sharks are an abundant, hardy species that is not actively fished.

When interpreting these findings, however, a few caveats must be noted.

First, sharks (and lobsters) are not the only animals to prey on urchins. Other predators include bony fishes, and more are likely to be identified in future.

Second, other factors can control urchin numbers, such as storm damage and the influx of fresh water.

And finally, it is unsurprising that we found a key predator when we intentionally searched for it by laying out food. Tethering urchins creates an artificial environment. We don’t know if the results would be replicated in the wild.

And even though we now know some shark species eat sea urchins, we don’t yet know if they can control urchins numbers.

But our research does confirm predators capable of handling large urchins may be more widespread than previously thought.

Jeremy Day, PhD researcher, University of Newcastle

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Meteorologists are again predicting a possible La Niña this summer, which means Australia may face wetter and cooler conditions than normal.

It would be the fourth La Niña in Australia in five years, and highlights the need for Australians to prepare for what may be an extreme weather season.

Typically, a La Niña or its counterpart, El Niño, signals its arrival earlier in the year. Signs of this potential La Niña are emerging fairly late. That’s where new research by my colleagues and I may help in future.

La Niña and El Niño explained

La Niña and its opposite phase, El Niño, are created by changes in ocean temperatures in the Pacific Ocean’s equatorial region. Together, the two phenomena are known as the El Niño Southern Oscillation.

The oscillation is said to be in the positive phase during an El Niño and the negative phase during a La Niña. When sitting between the two, the cycle is in neutral phase.

Earlier this month, the World Meteorological Organization said there was a 60% chance of La Niña conditions emerging by year’s end.

In the United States, the National Oceanic and Atmospheric Administration put the likelihood at 71%. Australia’s Bureau of Meteorology is in “watch” mode, predicting a 50% chance of a La Niña weather pattern forming later this year.

La Niña occurs when strengthening winds change currents on the ocean surface, pulling cool water up from the deep.

The winds also cause warm surface waters in the western Pacific and north of Australia, bringing increased rainfall and clouds. This usually means above-average rainfall and cooler temperatures for Australia, particularly in the east and north.

Conversely, an El Niño weather pattern generally brings hotter temperatures across Australia, and less rainfall in the east and north.

Paths of destruction

La Niña or El Niño events can cause devastation around the world.

The El Niño in 2015–16, for example, caused crops to fail and affected the food security and nutrition of almost 60 million people globally.

In Australia, El Niño events can bring increased risk of drought, bushfires and heatwaves, and water shortages.

Meanwhile, rainfall associated with La Niña conditions can lead to greater crop yield. But particularly heavy rainfall can wash crops away. It also heightens flood risks for some communities.

These far-reaching impacts mean it’s essential to plan ahead when a La Niña or El Niño is on the cards. But predicting these events has always been tricky.

Both types of events usually develop in the Southern Hemisphere autumn, peak in late spring or summer, and weaken by the next autumn. But it’s now late spring without a clear La Niña declaration. Why the delay?

Climate change is one factor. The Bureau of Meteorology says as oceans absorb heat from global warming, it’s harder to spot the specific warming patterns linked to La Niña.

The sheer complexity of the ocean-atmosphere system adds to the difficulty. The computer models used to predict El Niño and La Niña are improving all the time. But scientists still need more information on deep ocean processes, and how winds affect the oscillation.

Predictions are hardest during the Southern Hemisphere’s autumn. That’s because the cycle then is very susceptible to change – teetering at a point where either a La Niña or El Niño could develop.

That’s why the earliest an El Niño or La Niña can be predicted is usually around May or June.

But new research offers a way to predict the events much earlier – and start preparing if necessary.

Better, earlier forecasts

The study, which I led, assessed the likelihood of La Niña or El Niño events occurring in succession – either in the eastern or central region of the Pacific Ocean.

This distinction is important. For Australia, El Niño and La Niña events peaking in the Central Pacific, close to our continent, have greater impacts here compared to those peaking in the east, closer to South America.

We analysed weather observations, and the sequence of past El Niño and La Niña events, over the past 150 years. We also examined climate models for future changes in transitions between El Niño and La Niña events.

From this, we determined the likelihood of an El Niño or La Niña occurring in two consecutive years.

We found most El Niño events are followed by neutral conditions the next year (with a likelihood of 37–56%).

But La Niña behaves differently. In 40% of cases, a Central Pacific El Niño could follow an Eastern Pacific La Niña. And there is a 28% chance of two consecutive La Niña events in the Central Pacific.

These results allow for more advanced predictions. By identifying patterns in this way, the odds of an El Niño or La Niña can be predicted up to a year in advance.

Looking ahead

So, what does our research suggest for Australia? Will a La Niña develop here this year?

From September last year, Australia experienced a strong Eastern Pacific El Niño. So our findings suggest there is only a 17% chance of La Niña this year.

If the La Niña arrives, it will likely peak in the Central Pacific, potentially affecting Australia rainfall. But overall, any La Niña that develops this late is likely to be weak and relatively short-lived.

Our research also found that as climate change accelerates, the El Niño Southern Oscillation is likely to shift. For example, the odds of two consecutive El Niños peaking in the central Pacific region will likely increase. And we can expect fewer calm, neutral years between events.

We hope our research enables more accurate, long-range forecasts, giving communities additional time to plan and prepare.

Mandy Freund, Lecturer, Climate Science Geography, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Small plastic particles are everywhere: in the soil where our food is grown, in the water we drink and in the air we breathe. They got there from the plastic we throw away, which ends up in landfill sites, rivers and seas. There the plastic waste slowly breaks down, releasing tiny particles called microplastics and even tinier nanoplastics into the environment.

Microplastics are also increasingly being found throughout the human body. We are not sure how they got there, though there are three probable routes. We may ingest microplastics when we eat and drink, or breathe them into our lungs, or absorb them through our skin. Another route has recently been suggested, whereby microplastics get up our noses and from there into our brains.

For a long time, it was thought that the human brain existed in splendid isolation from the rest of the body. The so-called blood-brain barrier, a special layer of cells, protects the brain from all manner of pathogens and harmful substances. However, we now know that the blood-brain barrier can be breached because small plastic particles have been found in the human brain.

New research has suggested that the blood-brain barrier has at least one vulnerable spot where microplastics may be able to get into the brain. This potential entry point was suggested by researchers at the Freie Universität Berlin and the University of São Paulo. It is in the nose, where there are special nerves, the olfactory nerves, that detect smells.

The olfactory nerves run from the inside of the nose, through the skull, and then directly into part of the brain called the olfactory bulb. The researchers suggest that microparticles breathed into the nose may somehow get transported along the olfactory nerves and into the brain.

The researchers came to their conclusions by analysing tissue samples from residents of São Paulo who had died and undergone routine coroners’ autopsies. They removed the olfactory bulbs from these brains and analysed them using a variety of techniques.

Eight out of the 15 brains studied had microplastics in their olfactory bulbs. However, these eight samples had only 16 microplastic particles between them, which is perhaps some comfort.

Those 16 plastic particles included fragments, spheres and fibres, and were made of polypropylene, nylon and other plastics. Some of the fibres could have come from clothing. This makes sense because laundering clothes made from synthetic fibres is a significant source of microplastics in the environment.

Some of our small plastic particles are missing

The new study is just one of many that has reported the presence of small plastic particles in the human body. Most of these studies are about microplastics, which are particles up to five millimetres in size. Very few studies have looked for nanoplastics in the human body.

Nanoplastics are less than one-thousandth of a millimetre in size – so tiny that it is difficult to detect them without special equipment, and few scientists have easy access to this equipment.

The reason nanoplastics are important is that, unlike microplastics, they are well-documented to be harmful to living cells. This is because nanoplastics are small enough to get inside cells. Once inside, they can kill the cell.

Nanoplastics have been shown to kill cells in animal embryos. This can lead to birth defects in animals if the embryo is exposed to a high dose of nanoparticles.

Fortunately, there is no evidence that humans have suffered any great increase in birth defects in recent years. Maybe the placenta is able to stop microplastics and nanoplastics from reaching the foetus.

We need to know much more about the presence of microplastics – and especially nanoplastics – in the human body. And we need to know how they get there in the first place.

This makes the new Berlin-São Paulo study so interesting. It suggests a potential entry point, from the nose into the brain. This leaves us with the question: what potential risks are posed to our health by microplastics and nanoplastics? The jury is out, but perhaps feeling a little more nervous than before.

Michael Richardson, Professor of Animal Development, Leiden University and Meiru Wang, Postdoctoral Researcher, Developmental Biology, Molecular Biology and Nanotoxicology, Leiden University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

It’s been 20 years since a paper in the journal Science showed the environmental accumulation of tiny plastic fragments and fibres. It named the particles “microplastics”.

The paper opened an entire research field. Since then, more than 7,000 published studies have shown the prevalence of microplastics in the environment, in wildlife and in the human body.

So what have we learned? In a paper released today, an international group of experts, including myself, summarise the current state of knowledge.

In short, microplastics are widespread, accumulating in the remotest parts of our planet. There is evidence of their toxic effects at every level of biological organisation, from tiny insects at the bottom of the food chain to apex predators.

Microplastics are pervasive in food and drink and have been detected throughout the human body. Evidence of their harmful effects is emerging.

The scientific evidence is now more than sufficient: collective global action is urgently needed to tackle microplastics – and the problem has never been more pressing.

Tiny particles, huge problem

Microplastics are generally accepted as plastic particles 5mm or less in one dimension.

Some microplastics are intentionally added to products, such as microbeads in facial soaps.

Others are produced unintentionally when bigger plastic items break down – for example, fibres released when you wash a polyester fleece jacket.

Studies have identified some of the main sources of microplastics as:

• cosmetic cleansers
• synthetic textiles
• vehicle tyres
• plastic-coated fertilisers
• plastic film used as mulch in agriculture
• fishing rope and netting
• “crumb rubber infill” used in artificial turf
• plastics recycling.

Science hasn’t yet determined the rate at which larger plastics break down into microplastics. They are also still researching how quickly microplastics become “nanoplastics” – even smaller particles invisible to the eye.

Measuring the microplastic scourge

It’s difficult to assess the volume of microplastics in the air, soil and water. But researchers have attempted it.

For example, a 2020 study estimated between 0.8 and three million tonnes of microplastics enter Earth’s oceans in a year.

And a recent report suggests leakage into the environment on land could be three to ten times greater than that to oceans. If correct, it means between ten and 40 million tonnes in total.

The news gets worse. By 2040, microplastic releases to the environment could more than double. Even if humans stopped the flow of microplastics into the environment, the breakdown of bigger plastics would continue.

Microplastics have been detected in more than 1,300 animal species, including fish, mammals, birds and insects.

Some animals mistake the particles for food and ingest it, leading to harm such as blocked intestines. Animals are also harmed when the plastics inside them release the chemicals they contain – or those hitch-hiking on them.

Invaders in our bodies

Microplastics have been identified in the water we drink, the air we breathe and the food we eat – including seafood, table salt, honey, sugar, beer and tea.

Sometimes the contamination occurs in the environment. Other times it’s the result of food processing, packaging and handling.

More data is needed on microplastics in human foods such as land-animal products, cereals, grains, fruits, vegetables, beverages, spices, and oils and fats.

The concentrations of microplastics in foods vary widely – which means exposure levels in humans around the world also varies. However, some estimates, such as humans ingesting a credit card’s worth of plastic every week, are gross overstatements.

As equipment has advanced, scientists have identified smaller particles. They’ve found microplastics in our lungs, livers, kidneys, blood and reproductive organs. Microplastics have crossed protective barriers into our brains and hearts.

While we eliminate some microplastics through urine, faeces and our lungs, many persist in our bodies for a long time.

So what effect does this have on the health of humans and other organisms? Over the years, scientists have changed the way they measure this.

They initially used high doses of microplastics in laboratory tests. Now they use a more realistic dose that better represents what we and other creatures are actually exposed to.

And the nature of microplastics differ. For example, they contain different chemicals and interact differently with liquids or sunlight. And species of organisms, including humans, themselves vary between individuals.

This complicates scientists’ ability to conclusively link microplastics exposure with effects.

In regards to humans, progress is being made. In coming years, expect greater clarity about effects on our bodies such as:

• inflammation
• oxidative stress (an imbalance of free radicals and antioxidants that damages cells)
• immune responses
• genotoxicity – damage to the genetic information in a cell that causes mutations, which can lead to cancer.

What can we do?

Public concern about microplastics is growing. This is compounded by our likely long-term exposure, given microplastics are almost impossible to remove from the environment.

Microplastic pollution is the result of human actions and decisions. We created the problem – and now we must create the solution.

Some countries have implemented laws regulating microplastics. But this is insufficient to address the challenge. That’s where a new legally binding agreement, the UN’s Global Plastics Treaty, offers an important opportunity. The fifth round of negotiations begins in November.

The treaty aims to reduce global production of plastics. But the deal must also include measures to reduce microplastics specifically.

Ultimately, plastics must be redesigned to prevent microplastics being released. And individuals and communities must be brought on board, to drive support for government policies.

After 20 years of microplastics research, there is more work to be done. But we have more than enough evidence to act now.

Karen Raubenheimer, Senior Lecturer, University of Wollongong

This article is republished from The Conversation under a Creative Commons license. Read the original article.

It’s no secret Australia has abundant and cheap renewable energy, especially wind and solar power. But yes, there are times when the sun doesn’t shine and the wind doesn’t blow. We need energy storage to get us through those still nights and dreary days.

The Australian Energy Market Operator (AEMO) reports investment in storage capacity continues to increase, filling gaps left by retiring coal-fired power stations. But it warns sufficient storage is needed to ensure electricity supply is reliable throughout the transition.

Energy storage is the special sauce that makes renewables work anytime, anywhere and everywhere. Being able to send this stored renewable energy back to the grid on demand makes the most of the existing electricity network, including transmission lines.

We need both short- and long-duration storage to maintain energy security. This will enable renewable energy to be collected, stored and dispatched when needed. AEMO forecasts reliability levels can be maintained over most of the next ten years if programs and initiatives already established are delivered on time and in full. But we can’t afford any delays.

Storage on the grid

Old-fashioned power stations burning coal tend to run continuously, which helps make the electricity grid stable and reliable. In contrast, renewables need to be backed with storage such as batteries to provide a continuous supply of electricity.

The modern electricity network is being designed to handle the power produced when the sun is shining brightly and the wind is blowing hard, at the same time. But this only happens about 25% of the time.

Similarly, transmission lines are being built to a maximum capacity. But we could get by with fewer transmission lines if we store more solar and wind power for later. That’s why many renewable generation projects include storage on site or nearby, and why it also makes sense to have batteries in our homes or communities.

Australia has some of the world’s biggest batteries

The 300 megawatt Victorian Big Battery, near Geelong, is the biggest in Australia and one of the biggest in the world. It can store enough energy to power more than a million homes for 30 minutes.

The federal government is also funding six large-scale batteries through the Capacity Investment Scheme. This includes a 350MW energy storage system on the site of the Jeeralang Power Station, near Morwell in the Latrobe Valley. But the title of the nation’s biggest battery will soon be handed to the 850MW Waratah Super Battery in New South Wales.

What’s next?

Other emerging battery systems could power the future. For example, new lithium-sulphur batteries deliver more energy per gram and last longer than existing lithium-ion batteries. This has been achieved simply by adding sugar.

Australia has all the critical minerals needed to make batteries (lithium, nickel, copper, cobalt). But about 90% of the batteries we currently use come from China.

The 2024 National Battery Strategy vision is for Australia is a globally competitive producer of batteries and battery materials by 2035.

Battery booster scheme needed

Australia has the policy settings and incentives about right for building grid-scale storage systems. But almost half the effort in getting to 82% renewables by 2030 will come from consumers – mainly rooftop solar systems, backed by home and business battery storage.

We have just passed the point at which the payback period for small-scale batteries falls within the product’s lifetime, making the upfront cost worthwhile.

But government incentives are still needed to make it more affordable to install small-scale solar batteries. This would help families and businesses reduce their power bills, gain better control of when and how they produce energy, and build a more resilient energy system.

More than 300,000 solar power systems are installed on Australian homes and businesses each year. The total reached more than 3.7 million systems at the start of this year. With the right ambition and policy settings, we could have similar rates of uptake in home batteries – going from about 250,000 at the moment to more than one million by 2030.

What’s more, electric vehicles are essentially large “batteries on wheels”. They can be plugged in at home to provide backup power in blackouts, or at times of peak demand.

Government incentives are also needed here to drive the further uptake of electric vehicles in the domestic, commercial and industry sector. The upfront price of an EV is too high for many Australians. Perverse incentives such as the diesel rebate are also slowing the switch in some sectors such as mining.

Australia is already a world leader in rooftop solar. With the right policy levers, we can also lead the world in home energy storage.

The energy storage toolkit

Batteries alone aren’t enough. As the penetration of renewables increases, the importance of long duration energy storage technologies will increase. In general, these technologies provide more than eight hours of energy storage using various electrochemical, mechanical, thermal and mechanical means.

Beyond batteries, other energy storage solutions include pumped hydro such as Snowy 2.0, “green gravity” using mine shafts, green hydrogen and concentrated solar thermal power plants.

Get smart about storage

Many energy storage options are readily available now and could be manufactured in Australia. We have the technology to empower communities, create thousands of new jobs and help save the planet.

If we’re smart about it, we can even get by with fewer transmission lines and less bulky electricity infrastructure.

Scott Hamilton, Adjunct associate professor, Department of Chemical and Biological Engineering, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The electricity workforce will need to double in five years to achieve Australia’s 2030 renewable energy target, our new report finds. More than 80% of these jobs will be in renewables. Jobs in energy storage alone will overtake domestic coal and gas jobs (not including the coal and gas export sector) in the next couple of years.

The Australian Energy Market Operator (AEMO) updates its Integrated System Plan every two years. It’s a blueprint for the energy transition from coal to renewable energy. The plan lays out scenarios for how the electricity system might change to help put in place all the elements needed to make the transition happen.

AEMO and the RACE for 2030 co-operative research centre commissioned the Institute for Sustainable Futures to undertake modelling on the workforce needed for this transition. The “step change” scenario in the Integrated System Plan is broadly aligned with the 2030 renewables target. Under this scenario, we found the electricity workforce would need to grow from 33,000 to peak at 66,000 by 2029.

Rooftop solar and batteries together are projected to account for over 40% of these jobs. Wind farms will employ around one-third and solar farms just under 10%. Jobs would also treble in transmission line construction to connect renewables in regional areas to cities and other states in the next few years.

Job growth would surge in a ‘renewable energy superpower’

In the “green energy export” scenario, Australia becomes a “renewable energy superpower”. The country uses renewable energy to export green hydrogen and power heavy industry. In this scenario, the electricity workforce would almost treble to 96,000 by the late 2020s.

By 2033, after construction peaks, more than half of electricity sector jobs will be in operations and maintenance. This applies to both the step change and green energy export scenarios.

A significant employment downturn is projected during the 2030s. But in the green energy export scenario jobs then climb steeply again to a peak of 120,000. This projection reflects AEMO’s expectations of when green export growth will occur.

New South Wales is projected to have the most renewable energy jobs in the 2020s. However, Queensland would become the largest state for renewable jobs (especially in wind farms) in the green energy export scenario.

What are the other possibilities?

“Progressive change” is another scenario in the Integrated System Plan. For this scenario, we modelled slower growth in renewable energy. It reflects constraints on the economy and supply chains (including labour and minerals) for renewables.

In an “enhanced manufacturing” scenario, local renewable energy manufacturing increases. Our modelling found it could create a peak of 5,000 extra jobs.

Importantly, these projections don’t include upstream jobs in supply chains for the sector (for example, increased mining to supply the resources that renewables need) or electrification of homes.

Creating this many jobs is very challenging

Our modelling shows the workforce needs to grow very rapidly to make Australia’s energy transition happen. Unfortunately, the challenges of building this workforce are daunting. They include:

• there’s a shortage of almost all key occupations in demand for the electricity sector – electricians, engineers, construction managers – according to Australia’s Skills Priority List

• “extraordinary growth” forecast by Infrastructure Australia in other major infrastructure projects, such as transport, which will compete for many of the same skilled workers

• under AEMO’s scenarios, employment will be subject to boom-bust cycles, which increases the risk of skill shortages and damaging impacts, such as housing shortages, in regional areas

• Australia has relied heavily on skilled migrants – and will look to do so again – but many parts of the world are chasing the same workers.

The International Energy Agency has noted:

Labour and skills shortages are already translating into project delays, raising concerns that clean energy solutions will be unable to keep pace with demand to meet net zero targets.

What can be done to avoid skill shortages?

Some action has been taken to increase the workforce. The federal government, for instance, is subsidising apprentices under the New Energy Apprenticeship program.

But action isn’t happening at the scale and pace required.

What else can be done?

Firstly, Jobs Skills Australia and Powering Skills Organisation (which oversees energy skills training) have outlined ways to increase the system’s capacity to train more skilled workers. This includes creating better pathways into renewable energy for students, especially in recognised Renewable Energy Zones.

Secondly, Jobs Skills Australia has noted the need for renewable energy businesses to increase their intakes of apprentices. It recommends expanding the Australian Skills Guarantee to include generation and transmission projects.

The guarantee has set mandatory targets for apprentices or trainees to complete 10% of labour hours on Commonwealth-funded major construction and information technology projects (A$10 million plus). It could also be applied to major government funding programs for renewable energy and transmission. These include:

• the Capacity Investment Scheme, a government tender program to support a large volume of new renewables and storage projects

• Rewiring the Nation, a $20 billion fund for transmission lines

• grants from the Australian Renewable Energy Agency and the Clean Energy Finance Corporation.

Thirdly, government tenders could moderate the peaks and troughs in employment by limiting the maximum and minimum volumes built each year.

Fourthly, including more women and First Nations Australians can increase labour supply and workforce diversity. Only one-in-two First Nations Australians are employed compared to around two in three in the wider population. Yet they account for around one-in-ten people in some major Renewable Energy Zones.

Government pre-employment programs, working with industry and First Nations groups, could also increase the supply of workers. These could have a dramatic social impact too.

It’s a challenging problem whichever way you look at it. We need rapid change to build renewable energy capacity before coal plants retire and to tackle climate change. But that depends on growing the workforce amid skill shortages.

There’s a range of ways to increase the supply of workers and improve local outcomes. But we are running out of time. Urgent action is needed.

Jay Rutovitz, Research Director, Institute for Sustainable Futures, University of Technology Sydney; Chris Briggs, Research Director, Institute for Sustainable Futures, University of Technology Sydney, and Elianor Gerrard, Senior Research Consultant, Institute for Sustainable Futures, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

In arid inland Australia lives one of Australia’s rarest birds: the night parrot. Missing for more than a century, a live population was rediscovered in 2013. But the species remains elusive.

Until recently, Australia’s known night parrot population numbered in the tens of birds, scattered across desert in Queensland and Western Australia.

But our research team – consisting of Indigenous rangers and scientists – has made a breakthrough discovery. We’ve detected the largest known night parrot population in the world: perhaps as many as 50, living in WA’s Great Sandy Desert, on land managed by the Ngururrpa people. Our results are published today.

Urgent action is needed to protect these vulnerable populations and ensure the night parrot doesn’t go missing a second time, perhaps for good.

A highly mysterious species

The night parrot was once found throughout Australia’s arid inland, but its numbers plummeted in the late 19th century.

The bird was not definitely recorded for more than 100 years, until a dead bird was found near Boulia in western Queensland in 1990. Another dead bird was found in Diamantina National Park, also in western Queensland, in 2006.

In 2013 a small population was found by naturalist John Young in south-western Queensland. That area is now a wildlife reserve.

Night parrots are notoriously difficult to detect. They build tunnels in dense spinifex and hide there by day, emerging at night to forage. They are known only from populations in remote south-west Queensland and central and northern Western Australia. The species is critically endangered.

In Western Australia, Indigenous cultural knowledge about the species includes stories about how difficult the bird is to find. There are also whispered stories of mothers telling children the night parrot’s call was the sound of an evil spirit, and warning them not to stray from camp.

What we did

The Ngururrpa Indigenous Protected Area is in the Great Sandy Desert. It comprises vast areas of sandplains and dunefields, and smaller areas of floodplain and spinifex which are key night parrot habitats.

Ngururrpa Rangers worked with scientists to learn how to use sound recorders to search for night parrots. We then searched for the birds on Country between 2018 and 2023.

We combined the rangers’ detailed knowledge of habitats, water and seed resources with geology maps, satellite imagery and fire history data. From this we selected 31 potential roosting areas, then deployed sound recorders called “songmeters” at those sites.

We wanted to detect the night parrots’ distinctive calls which consist of whistles, croaks and bell-like sounds.

The acoustic data we gathered was then analysed to extract any bird calls in the night parrot’s frequency range. Potential detections were verified using a reference library of known night parrot calls.

Our results

We detected night parrot calls at 17 of 31 sites. Of these, ten were roost sites, where night parrot calls were detected in the hour after sunset and the hour before sunrise.

Individual night parrots are thought to have unique calls. We analysed how many different calls we could hear, and how loud they were (which can tell us when birds are calling from different locations). From this we built a picture of the identity and number of individuals regularly occupying a site.

We extrapolated this across the 58 patches of potential night parrot habitat on the Ngururrpa Indigenous Protected Area. We concluded up to 20 roosting areas may be occupied by night parrots.

Based on the numbers at roosting sites where we recorded calls, we estimate 40–50 night parrots could be present in the Ngururrpa Indigenous Protected Area.

Fire and predators pose grave threats

Once we found the night parrot populations, we wanted to know what threats they faced.

We used camera-traps to identify predators and also collected their scats (poos) to analyse their diets.

Dingoes were the predator detected most frequently in night parrot roosting habitat. Our cameras captured them ten times more often than feral cats. And we found dingoes regularly eat feral cats at night parrot sites.

Based on information from other areas, we suspect cats are a key predator of night parrots. Dingoes could be important in suppressing cat numbers and helping the parrots survive. So, attempts to limit predators in night parrot habitat should not harm dingoes.

We also analysed 40 years of satellite imagery to assess the threat of fire to night parrots’ roosting habitat. Based on the vegetation types and flammability of surrounding landscapes, we found bushfires sparked by lightning are a much bigger threat to night parrots in the Great Sandy Desert than in Queensland.

Strategic aerial and ground burning, to reduce fuel loads, already occurs in the Ngururrpa Indigenous Protected Area. As our knowledge of night parrots improves, these programs can become more targeted to protect key night parrot areas.

Keeping night parrots alive

A long-term monitoring program for night parrots on Ngururrpa Country should be established to help better understand and protect this vitally important population.

And the remote, wild nature of the landscape should be retained. This means minimising disturbance from people and vehicles, and continuing to exclude livestock and weeds.

Ngururrpa Ranger Clifford Sunfly exlpains how rangers want to help protect night parrots into the future:

We would like to spend more time on Country to find where [night parrots] are and understand what they are doing.

We want those scientists to come and help us catch some night parrots and tag them. We also need more snake-cams (inspection cameras) too and more songmeters. And a kit for collecting scats for DNA.

One day we would love to have our own research facility for doing our night parrot surveys. It would be our dream to have our own research base on Ngururrpa.

Rachel Paltridge, Adjunct Senior Research Fellow, ecology, The University of Western Australia; Clifford Sunfly, Ngururrpa Ranger, Indigenous Knowledge, and Nicholas Leseberg, Postdoctoral Research Fellow, School of the Environment, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Just as individual humans handle stress differently, so do corals. Even coral colonies of the same species, growing side by side, vary in their tolerance to pressures such as heatwaves.

In research published today, we discovered surprising new evidence of variable heat tolerance in corals. As the world’s oceans warm, these differences are important.

Earlier this year, the world’s fourth global mass bleaching event was declared. The Great Barrier Reef has suffered five mass bleachings since 2016 – most recently this past summer. The declarations followed the world’s warmest year on record.

To keep the world’s coral reefs healthy and functioning, global carbon emissions must be dramatically curbed to reduce the rate of ocean warming. As humanity works towards that goal, interventions may buy time for corals to survive in their warming environments.

What we did

The heat tolerance of corals can be measured by analysing their responses to elevated water temperatures. Our research involved measuring the bleaching thresholds of more than 500 colonies of the tabular coral, Acropora hyacinthus.

Acropora hyacinthus is a common coral that forms “tables” of tiny branchlets. This species is both ecologically important and highly vulnerable to heat waves, making it a prime candidate for conservation.

The characteristic colour of coral is provided by algae living inside its tissue. The algae also provide most of the coral’s nutrition. When water temperatures get too high for too long, the coral expels the algae, causing it to bleach and starve.

While at sea, we visited 17 reefs to scuba dive and search for Acropora hyacinthus. We then brought samples of these corals on board a research vessel to conduct experiments.

Our specially designed portable experiment system contained 12 tanks set to four different temperatures. Coral fragments were placed in each tank and subjected to short-term heat stress at different temperatures.

Afterwards, we measured the amount of pigment left in the coral fragments, which directly aligns with the amount of algae left in the coral’s cells.

We then determined each coral’s bleaching thresholds - in other words, the temperature at which the coral’s pigmentation drops to 50% of its healthy level. This allowed us to understand how much variation exists and where the most heat-tolerant colonies live.

So what did we find? Under our experiments, the amount of pigment retained under high temperatures varied from 3% to 95%. This means at high temperatures, some coral colonies completely bleached while others seemed barely affected.

Of the 17 reefs we studied, 12 contained colonies with bleaching thresholds in the top 25%. This means heat-tolerant corals could be found at most of the reefs we sampled.

Nature versus nurture

Corals handle stress differently for two reasons: nature and nurture.

Each coral has a unique “nature” or genetic makeup that can affect its heat tolerance. Our results suggest corals found across the entire Great Barrier Reef may hold unique genetic resources that are important for recovery and adaptation.

However, aspects of the marine environment may nurture, or hinder, a coral’s heat stress response. These include water temperatures, nutrient conditions, and the symbiotic algae living inside coral tissue.

We found corals living in warmer regions, such as the northern Great Barrier Reef, can handle higher water temperatures. However, because the water is so warm in these areas, the corals are already pushed close to their temperature limits.

Corals in the southern Great Barrier Reef cannot handle temperatures as high as their northern neighbours. Our findings suggest these corals can tolerate more warming above their local temperatures than corals to the north.

These tolerance patterns may affect which corals survive marine heatwaves.

Giving our reefs a future

Our findings have potentially important implications for the ability of corals to adapt to warmer seas under climate change.

The results may also inform reef restoration and conservation efforts. For example, heat-tolerant parent corals could be selectively bred to produce offspring better suited to warmer waters.

The success of such programs depends on the extent to which a coral’s genetic makeup controls its tolerance to heat. So, the next step in this research is investigating these genetic differences.

Selective breeding trials are already underway, using the most heat-tolerant corals identified in this study.

When it comes to protecting our coral reefs, reducing greenhouse gas emissions is imperative. However, interventions such as selective breeding may be useful supplements to give coral reefs the best future possible.

Melissa Naugle, PhD Candidate in Coral Ecology, Southern Cross University; Emily Howells, Senior Research Fellow in Marine Biology, Southern Cross University, and Line K Bay, Research Program Director, Australian Institute of Marine Science

This article is republished from The Conversation under a Creative Commons license. Read the original article.