The world’s hottest years over the past decade have coincided with stagnant economic productivity, rising prices and geopolitical instability.

Is this just coincidence or has the current level of climate change been one of the drivers? Climate change is often framed as a problem for the future. But how much economic damage has today’s current level of ~1.35°C of warming already caused?

To answer that question, we analysed the effects of climate change to date on the New South Wales economy. The results were released today as part of a Net Zero Commission report.

We estimate climate change has already caused median losses of around 18% (probability range 4–33%) to the NSW economy, the biggest economic jurisdiction in the country. At a median 18% loss, that translates to about A$21,300 per person on average in yearly income.

We show that it’s not local bushfires or flooding that are driving the majority of damage, but changing global weather that in turn affects our cost of living.

Imagine a world without climate change

Studies typically project the global economic damage that climate change will do by 2050 or 2100.

Some influential estimates have suggested climate damage would be fairly small. But our recent research and work by others shows the economic damage coming down the pipeline could be more than four times larger than previously thought.

Our research question for this report was different: “What would the NSW economy look like today if historical emissions of greenhouse gases had not caused climate change?”

This requires a thought experiment: imagining a past where we burn fossil fuels at the historical rate, but the additional carbon dioxide and other atmospheric gases do not cause changes to temperature or rainfall patterns.

Answering this question will allow us to understand the economic losses we have already endured from historical climate change.

How we did it

First, we collected data on historical economic growth and weather across the world over the past 70 years. We then modelled how weather changes (or shocks) impacted economic growth over this period. There is significant debate on how to do this, so we adopted a variety of approaches.

Then we had to plausibly guess at how the weather would have evolved in the past four decades without climate change. To create this hypothetical weather series, we simply removed any trend found in the weather data which we ascribe to human-caused climate change. This works because there is no evidence natural causes have contributed to the upward trend in temperatures.

Finally, we compared economic growth rates predicted by the models under the observed and under the hypothetical weather conditions. The contrast between the total economic production of the NSW economy in the two scenarios is the economic cost of historical climate change for a given year.

What we found

We estimate the median economic loss for NSW in 2024 was 18%. There is significant uncertainty in this figure, with the lower estimates around 4% and the higher around 33%.

The median loss figure of 18% translates into an average of $21,288 in losses per person in yearly income (in 2023–2024 dollar values). In other words, the model finds that if historical warming had not occurred then people living in NSW would each have $21,288 more dollars, on average, in their pockets every year. This amount is large enough to meaningfully improve the quality of life of the state’s average household.

The models suggest the primary mechanism through which this loss has occurred is the rise in the global average temperature. When people think about losses associated with climate change in NSW, they might consider how climate change exacerbated the bushfires of 2019–20, or the floods that followed. The damages they caused are, of course, real and significant.

However, the economic models suggest the majority of the damage has come from shifts in weather globally. Given the interconnectedness of modern economies through trade and global supply chains, it is reasonable to assume that climate shocks to supply chains affect the whole globe.

How we think about climate change

When pollsters ask Australian voters what issues they care about, “climate change” is often listed as one issue among many. Voters are asked to assess how important climate change is to them relative to the cost of living, public health, interest rates, secure employment, and other important things.

Presenting issues in this way reinforces a common misconception that they are independent, and that one can be prioritised over the other.

To the contrary, there is now good evidence that climate change is strongly related to economic outcomes, which in turn drive the cost of living, interest rates, investment in in health and education and the labour market.

It’s time to stop thinking of climate change as “merely” an environmental issue, which can be discarded when economic times are tough. Instead, we should recognise what it really is: a current and ongoing threat to our standard of living.

Timothy Neal, Senior lecturer in Economics and the Institute for Climate Risk and Response, UNSW Sydney and Ben Newell, Professor of Cognitive Psychology and Director of the Institute for Climate Risk and Response, UNSW Sydney

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

Picture sea ice in your mind. You probably imagine brilliant white, snow-covered floes floating on the surface of the ocean, home to penguins in the south of the globe or polar bears in the north.

But our new research shows Antarctic sea ice can turn into rafts of rotting floes (the free-floating pieces of ice) or an icy green slush when it interacts with waves in the stormiest ocean on the planet.

We now know the wave-driven processes that cause the surface of the sea ice to melt are a “missing link” in understanding what’s driving the increasing Antarctic sea ice melt each summer.

These processes can dramatically increase the rate the ice melts, with major implications for the global climate and Antarctic marine ecosystems.

Our planetary heartbeat

Each year, the sea ice that hugs the coast of Antarctica expands from 3 million square kilometres in summer to 19 million square kilometres in winter, stretching far north into the Southern Ocean. As the sun rises and the temperatures increase, it retreats again.

This remarkable seasonal change is like a heartbeat within our planet’s climate system, moderating global temperatures, driving ocean circulation and forming a unique habitat for a plethora of living organisms, all adapted to its seasonal rhythms.

The annual summer sea ice melt is particularly remarkable because it occurs over only three months. But even the most sophisticated climate models underestimate the rapid rate of sea ice retreat each summer.

How do waves melt sea ice?

Until now, the waves travelling from the ice-free ocean into the area covered in sea ice had only been studied for their role in breaking up ice floes. We knew these smaller floes were prone to melting around their sides and bottoms as the ocean was heated by the sun as summer progressed.

But this is not the full story.

We now know waves also flood over ice floes, washing away the bright snow cover that shields the underlying ice from sunlight and creating ponds of seawater on the floe surfaces.

Due to their reduced brightness, the snow-free ice and these “wave ponds” absorb substantially more solar heat than snow-covered ice, and this melts the ice from the top down. Moreover, the snow-free ice and wave ponds are oases in which algae thrive, turning the ice and ponds green and absorbing even more heat from the sun.

The waves also pulverise the floes into small fragments and slush. Under the right conditions, the combination of wave flooding, algal greening and pulverisation turns the sea ice cover into a slushy mixture, resembling a green soup.

We estimate that flooding, ponding and pulverisation can increase summer-time ice thinning by over 4 centimetres per day. Algal greening can add an additional 1 centimetre of thinning per day. These are extraordinary accelerators of ice melt, considering that most Antarctic sea ice is less than 1 metre thick at the end of winter.

Waves are also generated deep within the Antarctic sea-ice region by winds blowing over large openings in the ice cover. In this way, wave melt processes eat away at the ice cover from within, as well as from the edge throughout summer.

Feedbacks could trigger further melt

Our ice melt estimates are significant, yet they are likely underestimates. They do not account for amplifications to melting caused by so-called “positive feedbacks”.

For example, the ice darkening caused by waves removing the snow, ponding and pulverisation substantially increases the amount of sunlight absorbed by the ice. This causes additional surface and interior melting, which further reduces the ice brightness. And this causes more vertical melting, and so on, in an amplifying cycle.

We propose that this positive feedback is strengthened by algal greening that further darkens the ice, leading to further absorption of sunlight and melting.

Exactly how much these feedbacks would cause further ice melt is tricky to quantify, so we have left this as an exciting future research challenge.

Ponds at both poles

The Antarctic “wave ponds” we have observed are the seawater equivalent of “melt ponds”. These form extensively across Arctic sea ice in summer from pooling snow meltwater.

These freshwater melt ponds have been intensively studied and integrated into climate models, because of their important role in the rapid decline in the coverage and thickness of Arctic sea ice over recent decades.

Unlike melt ponds, seawater wave ponds occur year-round. Although they only occur in regions where sea ice interacts with ocean waves, this encompasses a large proportion of Antarctic sea ice over the course of a year.

The future of Antarctic sea ice

The effects of wave melt, greening and associated feedbacks are likely to intensify on sea ice around Antarctica over coming decades. Climate change is predicted to increase wind speeds and wave heights across the polar Southern Ocean.

This disruption of the annual sea ice cycle and further sea ice loss has serious consequences for global climate and marine ecosystems.

We need further observations using autonomous camera systems on icebreakers and modelling research to better understand these wave processes and their overall influence on Antarctica’s sea ice cycle.

These advances are vital to understanding the causes of recent dramatic sea-ice losses around Antarctica, and promise vital insights about the future of the icy south and our Earth system.

Luke Bennetts, Professor of Applied Mathematics, The University of Melbourne; Bonnie Light, Physicist, University of Washington; Petteri Uotila, Professor, University of Helsinki; Philip Reid, Scientist, Australian Bureau of Meteorology, and Rob Massom, Leader, Sea Ice Section, Antarctic Climate Program, Australian Antarctic Division

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

Trees take carbon dioxide from the air and turn it into wood, storing it for decades. This is why Australian authorities have made forest regeneration eligible for carbon credits.

The largest carbon farming scheme is known as human-induced regeneration. Here, land owners and managers support forests to return on once-forested land. Every tonne of carbon dioxide soaked up by regrowing trees is worth one Australian carbon credit, about A$37.50.

The scheme has around 42 million hectares of land on its books. But only a third of this area is eligible for carbon credits, as the land has to be assessed as likely to regenerate into forest under changed management.

In recent years, some projects have come under fire. Researchers have suggested there’s not enough regeneration or that regeneration would have happened anyway. But independent assessment of these claims suggest these concerns are overblown.

As someone responsible for formally reviewing almost 100 of these projects since 2023, I have visited many sites and verified the data. Overall, I found these projects were being managed well – and forests are regrowing.

How does carbon farming work?

Under the rules, the area can’t have been forested for at least a decade before the project starts. It must have a high likelihood of becoming forested and richer in carbon through regeneration.

If left alone, trees will naturally regrow unless something stops them. Grazing by livestock, feral animals and sometimes native animals is the biggest barrier.

Many regeneration projects are in semi-arid areas with limited water. If water is made freely available for livestock, it can lead to surging numbers of kangaroos, wallabies and other native animals that eat regenerating saplings. This is why one method of limiting grazing is removing artificial watering points.

Fencing is another method. Australian and international researchers have found trees and vegetation on degraded land usually regenerate better when behind fences, though not always.

Does it work?

Australian authorities define a forest as an area dominated by trees over two metres tall, with existing or potential taller trees covering 20% or more of the area.

Participants have to prove forests of local tree species exist in the surrounding area, show the land can support forest and that there are sources of seeds. They also have to show evidence the area could be considered forest 20 years or so after the project begins.

Before carbon farmers can earn credits, the evidence they supply is audited and reviewed by teams of independent experts.

As one of these experts, I have reviewed a great deal of evidence and been on site when data was collected by independent ecologists to confirm how accurate tree cover estimates are. They’re not perfect. But they are very good.

If regeneration is too slow or fails, the area can be removed from the scheme. To date, about 6% of the land considered likely to regenerate has been taken off the scheme. Put another way, that means forests are actually regrowing on 94% of the land considered likely to regenerate.

Is criticism warranted?

Prominent critics have questioned the link between stopping grazing and regenerating forest. If this critique was accurate, it would mean there was no permanent boost to forests by ending grazing.

They argue instead in favour of only giving carbon credits to projects where trees are actively planted on previously cleared land.

The problem is, planting is relatively expensive and can be limited in scope. Planting also requires great care in tree species selection and genetics.

By contrast, removing pressure and allowing forests to naturally regenerate avoids these issues. Natural regeneration can also work in areas where planting and tree management would be expensive.

The critics used national-scale maps of woody vegetation to argue tree cover on some projects was falling short.

But as other experts have pointed out, these criticisms don’t stack up. The maps and models they rely on underestimate tree cover, compared to local and precise data gathered by aircraft with high-resolution scanning lasers.

When regeneration areas are independently assessed using similar gold standard methods, almost all show clear signs of regenerating forest.

Where does this leave us?

Worldwide, there are very real and well documented problems with carbon credit schemes intended to protect or restore forests.

This is why it’s important to scrutinise Australia’s human-induced regeneration scheme and others like it. But not all criticisms are valid.

The good news is, gold standard data gathered by participants cross-checked with regular on the ground audits and reviews show the scheme is largely working.

Regeneration can be slow, even after livestock have been removed. Some heavily degraded areas may not regenerate at all. But overall, it is leading to more forests and more carbon stored.

Under Australia’s carbon credit rules, all methods of producing credits expire after ten years. As a result, the human-induced regeneration scheme closed to new participants in 2023. Policymakers are working on new nature-based solutions to store carbon and boost wildlife on privately managed land.

But for the foreseeable future, forests will quietly regrow on huge tracts of land – and their successes and failures will be tracked and measured to make sure Australia has more trees than it would have otherwise.

Cris Brack, Associate Professor, Forest Measurement and Management, Fenner School of Environment and Society, Australian National University

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

We’ve all been there: just as you’re about to fall asleep, you notice a huntsman spider on the ceiling. Or you walk into your kitchen and find a long trail of ants snaking into your pantry.

Given there are an estimated 10 quintillion individual insects alive on Earth at any one time, it’s no surprise they sometimes find their way into our homes. In fact, the average Australian shares their home with around 100 different insect and spider species.

But the reality is most of these tiny housemates won’t hurt us, and you really don’t need to kill them. In fact, many perform helpful jobs such as catching flies and mosquitoes, or tidying up crumbs.

So, what can you do instead?

Starting with spiders

Remember: many spiders in your home are harmless.

Common spider housemates include:

• huntsman spiders (Sparassidae sp)
• black and brown house spiders (Badumna sp) and
• daddy long-legs spiders (Pholcus phalangioides).

They’re big and speedy, but huntsmen are gentle giants that rarely bite and their venom can’t hurt humans. They are naturally timid animals that will usually try to avoid us big, scary humans.

Black and brown house spiders live in messy webs often on screen doors or in corners. They are sometimes mistaken for funnel-web spiders, and while their venom can cause unpleasant symptoms such as nausea and swelling, they are generally timid and rarely bite.

Daddy long-legs spiders are the source of an urban legend claiming they are the most venomous spider in Australia, but have jaws too weak to break human skin. This is false; there’s no evidence these lovely spiders have venom capable of harming a human.

There have been no confirmed deaths from a spider bite in Australia in nearly 50 years, partly due to the introduction of effective antivenom and partly because most spiders are very reluctant to bite.

In fact, you are far more likely to be killed by a dog, cow or kangaroo than by a spider.

Even redbacks are shy and non-aggressive and will often play dead rather than bite; most bites occur when the spider is accidentally squeezed, such as when moving a pot plant or putting on a shoe. Although their venom can make us unwell, no one has died from a redback bite since antivenom was introduced in 1956.

While a bite from a Sydney funnel web spider (Atrax robustus) should always be treated as a medical emergency, effective antivenom treatments mean no one has died from a funnel-web bite since 1981.

What about ants and flies?

Most ants in the house are harmless. They are likely scavenging for food, looking for water, or may even be passing through on their way to somewhere else.

Having said that, sometimes it’s hard to figure out what they’re doing. I have a trail of ants that runs up my shower wall – I have no idea what they are doing or why they are there. They’re just part of the family now.

Some people worry insects can spread disease. Yes, cockroaches, ants and flies can potentially transfer bacteria from one surface to another but this is rarely a problem in our homes since a single fly touchdown is unlikely to transfer enough bacteria to cause issues. Our homes also don’t typically have rotting food or faeces lying around where insects can touch it and spread germs elsewhere.

What should I do about them?

In many cases, you don’t have to do anything; the bug or spider in your house is likely harmless and won’t cause problems.

And growing evidence suggests at least some insects, including crickets, can experience pain or pain-like states.

While scientists still debate exactly what insects experience, it’s increasingly clear insects and spiders are far more behaviourally and neurologically complex than once assumed.

Is it really worth causing suffering to an animal that has done nothing wrong other than share your space?

Instead, consider simply capturing the animal in a container and sliding a piece of cardboard or plastic underneath before releasing it outside.

If you live with a phobia, perhaps you could ask a friend or neighbour to do it for you.

To make your home less attractive to insects and spiders, you can:

• cover food sources, including pet food
• clean up any spilled foods, crumbs or food residues
• store loose food in sealed containers to prevent pantry moths and grain beetles
• make sure your bin seals properly when closed
• ensure your windows have well-fitting fly screens.

Only if everything else fails — or if the spider or insect is genuinely dangerous, which is rare — should lethal control such as pesticides or squishing be considered.

Remember: household insecticides are not necessarily harmless. Some studies have linked insecticide exposure to a range of health concerns (particularly in children).

Learning to live with them

The minibeasts in our homes are fascinating to watch and can provide a source of entertainment and education.

Kids (and adults!) can learn a lot about nature, ecology and science from watching insects and spiders at home. In fact, keeping and observing an insect has even been used as a successful form of therapy for children.

It’s OK to be scared of insects and spiders, but perhaps we should approach it the same way we approach fear of dogs or other furry animals: not through killing but by acknowledging the fear and working towards managing it.

Tanya Latty, Associate Professor in Entomology, University of Sydney

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

It’s surprising how easy it is to see a koala every day in Australia’s major cities.

The cute, grey marsupial can be found on t-shirts, hanging off people’s bags and pencils, and decorating any decent souvenir shop. But seeing a real koala in the wild has become increasingly tricky in some parts of the country. The iconic marsupial is now listed as endangered in Queensland, New South Wales and the Australian Capital Territory.

But koalas have been in a similar situation before.

As my new study published in the journal Molecular Biology and Evolution shows, koalas experienced a population crash about 100,000 years ago. This finding rewrites our understanding of the genetic history of koalas in Australia – and overturns previous theories about what caused their decline in ancient times.

Turning to the genome

Fossil records of koalas are extremely rare. This makes it difficult to estimate how many koalas were present in the past.

Instead, genomes provide important clues about their evolutionary history. The genome acts as a historical record. It preserves genetic information from ancestral populations that can be used to determine their population size.

Previous genomic studies of koalas have estimated koalas experienced a major population decline roughly 40,000 years ago. This was shortly after the arrival of humans in Australia, suggesting this may have been a contributing factor.

Yet the impact of human arrival on Australian fauna is hotly debated. Some researchers use it to explain the widespread extinction of megafauna during this period.

My new study challenges this theory.

Pushing the timeline back 60,000 years

My colleagues and I set out to construct the first estimate of the koala mutation rate. This is simply the number of mutations that appear in each generation.

Estimating the historical population sizes that have shaped mutation patterns in the genome relies heavily on knowing how often new mutations arise. The problem is that each species has its own unique mutation rate.

To estimate the mutation rate in koalas, we sequenced the genomes of 12 koalas from three families, comprising seven parents and five offspring. This allowed us to count the number of new mutations over each generation.

The whole koala genome has about 3.4 billion sites where changes could occur. We found only 25 mutations per offspring. That’s the equivalent of searching for 25 wrong letters scattered across more than 1,000 copies of The Lord of the Rings trilogy.

We then applied this mutation rate to 457 koala genomes sampled across their entire range. This allowed us to investigate how koala populations have changed over time – including when their numbers crashed.

We found koala population declines occurred around 100,000 years ago – well before humans arrived in Australia. This effectively rules out humans as a cause of the population crash.

Although the mutation rate is a fundamental evolutionary concept, we surprisingly have very few estimates for Australian species. Our estimate is the first from Diprotodontia, the marsupial order which also includes wombats, kangaroos and possums.

Previous studies estimating historical population sizes in koalas have had to rely on mutation rate estimates from distantly related placental mammals such as humans and mice. Applying the koala mutation rate has rewritten the genetic timeline for koalas.

So, what caused the crash?

The koala population crash 100,000 years ago matches a period of intense environmental change across Australia.

The Pleistocene (2.5 million to 11,700 years ago) saw repeated glacial periods, characterised by cold and dry conditions, as well as repeated interglacial periods, characterised by warmer and wetter conditions.

As Australia became drier, the expansion of the Nullarbor Plain established a vast semi-arid shrubland across southern Australia, shrinking suitable koala habitat and separating eastern and western koala populations.

Unfortunately, the population west of the Nullarbor Plain (which was recently described as a distinct species from the modern koala) went extinct around 28,000 years ago.

Although eastern populations were restricted to a small patch of forest on the east coast, they persisted through harsh glacial conditions. Over the last 17,000 years, as conditions became warmer and wetter, they expanded and formed the five genetic groups that are now distributed along the east coast of Australia.

Given our results, we’re now curious to see if other Australian species, including the closest relatives of extinct megafauna, also experienced population declines before humans arrived.

Koalas are back to hard times

Koalas are once again experiencing population declines across Australia.

One similarity between modern and ancient declines is they are both largely driven by reductions in the amount of suitable habitat. The ancient decline was driven by global glacial cycles – an unavoidable result of Earth’s orbit.

However, recent declines have generated a similar bottleneck over a much shorter time window, due to the historical and continued removal of suitable koala habitat. This is made worse by other threats such as hunting, disease, vehicle strikes, feral dog attacks and bushfires.

Fortunately, most koala populations have only recently started losing genetic diversity, and rapid population recovery can prevent further loss and inbreeding.

Hopefully the eastern koala will persist once again.

Toby Kovacs, PhD Candidate, School of Life and Environmental Sciences, University of Sydney

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

When a whale dies, a very special natural phenomenon can come alive. The carcass might float at the surface for some time, attracting sharks and other predators. As it becomes weathered it may start to sink, falling through the water until it eventually settles on the seafloor where deep sea scavengers feast upon it.

The scientific record of “whale falls” is sparse and fragmentary. But a team of researchers, led by Xiaotong Peng from the Chinese Academy of Sciences, has discovered a vast and ancient whale necropolis in the Diamantina Zone in the southeastern Indian Ocean.

The site, described in a new paper published in Nature, dates back more than five million years and is one of the deepest known whale fall ecosystems in the world.

A whale-sized find in the middle of the ocean

During a special dive mission in February 2023 using a submersible called the Fendouzhe, the team of scientists discovered extensive whale skeletons and fossils partially buried in sediment on the seafloor.

Following the initial discovery, the team made 32 more dives to the seafloor over the next month, mapping the extent of the necropolis.

It stretched roughly 1,200 kilometres along the seafloor at depths of between 4,200 and 7,000 metres. It contained 476 whale fossils as well as five active whale falls.

These active whale falls were teeming with many strange-looking creatures, including jellyfish, brittle stars and bone-boring worms – many of which may be new to science, according to the researchers.

From the 43 fossils the team recovered, they identified five beaked-whale species, including the Andrews’ beaked whale (Mesoplodon bowdoini) and the strap-toothed whale (Mesoplodon layardii) which are known to inhabit the region, and one species of baleen whale – the sei whale (Balaenoptera borealis).

The largest find was a dead Antarctic minke whale, five metres in length, which the team identified from its distinct ear bone shape, as well as genetic analysis. The team also identified a new whale species – Pterocetus diamantinae – which is now extinct.

Isotopic dating, where scientists use the decay of radioactive isotopes, revealed that the oldest fossils from the site are about 5.3 million years old.

The high concentration of whale remains in the region raises the question of how exactly this graveyard was formed. The authors suggest the reason probably has to do with the V-shaped topography of the Diamantina Zone which funnels carcasses onto the seafloor, plus the fact that many deep-diving beaked whale species are known to inhabit this part of the ocean.

A reminder of how little we know

This work deepens our our understanding of whale falls and the incredible ecosystems they support. It also deepens our understanding of beaked whales – usually offshore species which routinely dive up to 1 kilometre and hold their breath for more than an hour.

The finding of five million-year-old fossils provide an evolutionary window into the history of beaked whales from the Pliocene epoch to the present day.

This research is also a humbling reminder of how little we know of the deep sea – and how when we look for something, we may just find it, and so much more.

Vanessa Pirotta, Postdoctoral Researcher and Wildlife Scientist, Macquarie University

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

The Australian government has launched its largest-ever lawsuit, suing American chemical giant 3M and its local subsidiary. The government is seeking A$2 billion in damages for the past and future cost of investigating and managing “forever chemicals” contamination from firefighting foams on almost 30 Defence sites.

The government alleges the company withheld internal testing that showed these foams did significant environmental damage. 3M has vowed to defend itself.

What’s interesting is the scope. State-owned facilities, such as public water utilities, are unlikely to be included. The case also avoids any mention of possible impacts on human health. This is at least in part because the impacts of forever chemicals are a live topic of scientific debate and inquiry.

What is the case based on?

Forever chemicals are properly known as PFAS, or per- and polyfluoroalkyl substances. They are also known as “forever chemicals” because they take a very long time to break down in the environment.

The Commonwealth case focuses on the use of PFAS-containing firefighting foams manufactured by 3M and used on Defence bases from the 1970s until the mid 2000s. These aqueous film-forming foams have been slowly phased out in Australia.

Several communities near affected Defence facilities have sued the Commonwealth, with class actions and other claims amounting to around $400 million in legal settlements.

Until now, the government hasn’t sought to recover these costs, but is doing so now to remediate the sites, pay out class actions and cover future remediation.

While full court documents are not yet public, multiple government statements and the court file suggest the claim is mainly based on the Australian Consumer Law.

The Commonwealth may argue 3M engaged in misleading or deceptive conduct by failing to disclose what it knew about the environmental risks of these firefighting foams.

In the United States, many state attorneys-general have sought to recover clean-up and monitoring costs from manufacturers allegedly promoting PFAS products as safe, despite knowing their risks.

How likely is a settlement?

While both sides appear to have adopted a firm public position committing to the case, this isn’t guaranteed. Large lawsuits like this frequently reach a settlement before trial.

This is because reaching a settlement allows parties to agree on compensation without a judicial finding of liability.

Australian courts encourage alternative dispute resolution, which can enable settlements and reduce costs and uncertainty, while allowing defendants to avoid formal findings of wrongdoing. Class actions against Defence have all settled before trial.

In the US, municipal governments and water authorities sued 3M and other PFAS manufacturers for selling products they knew would contaminate the environment, seeking payments to “help clean up the mess that they created”. These claims became part of a larger case.

In response, 3M agreed to pay about A$14 billion (US$10 billion) to assist with testing and treatment costs while denying liability.

Settlements have also been reached in personal injury litigation, including one against another manufacturer, DuPont, worth A$953 (US$670) million across 3,550 claims.

What’s in and what’s out of the case?

The proceedings have been framed as an effort to recover past and future costs from almost 30 Defence sites.

Yet PFAS contamination isn’t limited to these sites. Other sites of concern include state-operated firefighting facilities, industrial sites and public water supplies. This case is unlikely to directly address those locations.

It’s not clear whether any funds recovered would support measures sought by affected communities, such as routine blood testing or long-term medical monitoring. Residents of Katherine in the Northern Territory have questioned whether any potential settlement would compensate losses not covered by earlier class actions. Many civilian and military firefighters exposed to these PFAS foams for decades have not been involved in compensation schemes or major litigation.

Notably, the case doesn’t mention any possible effects on human health. Assistant Minister for Defence Peter Khalil has cited advice from health authorities that evidence of health impacts from forever chemicals remains limited.

In 2023, the cancer agency of the World Health Organization found one forever chemical, PFOA, was carcinogenic. But there are many different types of PFAS. The WHO is now conducting a systematic review of key PFAS compounds and health outcomes, such as cancer and reproductive toxicity.

The PFAS class actions against Defence similarly excluded personal injury claims, focusing instead on property, business and cultural losses. Even so, evidence about possible health effects was raised because contamination affected property values.

It will be interesting to see whether the Commonwealth can separate environmental contamination from health concerns, while maintaining its position that evidence of human health impacts remains limited.

What’s next?

If the lawsuit goes to a trial and the government succeeds in its claim, it would likely open the door to further claims against 3M by fire services, water suppliers and other affected groups.

This could also happen if the claim is settled out of court.

Regardless of the result, more legal action and advocacy is likely from communities affected by PFAS around Australia.

Cameron Holley, Professor, UNSW Law & Justice and UNSW Institute for Climate Risk & Response, UNSW Sydney and Carley Bartlett, Postdoctoral Research Associate in Law and Justice, UNSW Sydney

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

Summer heatwaves are currently receiving a lot of attention in Europe because they now cause more deaths than floods or storms.

But winters are also warming. While they are generally less deadly, they influence and disrupt human and natural systems in many subtle ways.

Aotearoa New Zealand has experienced a particularly warm start to this winter, with record high June temperatures in the capital and warm conditions across the country.

Many will welcome the unseasonably warm weather, but milder winters have a range of impacts, especially for plants and insects.

Extra winter growth, but loss of carbon

In forests, warmer temperatures can extend the growing season of trees.

Usually, many trees are dormant during winter as conditions are too cold for growth. But our ongoing measurements of kauri tree growth in Auckland indicate trees have continued to grow throughout recent winters.

One might assume a longer growing season would increase carbon uptake and storage in trees. However, overall carbon changes are actually negative because warmer temperatures also increase respiration, which returns more carbon to the atmosphere.

In Aotearoa, few plant species lose their leaves in winter. But according to traditional Māori knowledge (mātauranga Māori), flowering time has changed and fruit biomass has declined with warming in forests of the central North Island since the 1950s.

This has had a negative impact on the numbers, breeding rates and health of kererū (native wood pigeons) and has reduced nutrient cycling in the soil.

Risk of new invasions

Insects are also very sensitive to winter temperatures.

Like trees, many insects have a dormant period during colder months. Some insects from warmer climates have established as pests in Aotearoa, but they usually struggle to survive cold conditions. As winters warm, the numbers of species able to get through the cold season is increasing.

For instance, in temperate climates such as in New Zealand, wasp colonies have a strong seasonal cycle. Wasp numbers increase during spring after the queen emerges from overwintering and lays eggs. The workers expand the colony during summer but when temperatures drop in autumn, most of them die off.

However, in warmer conditions, sightings of winter-active workers have increased in Aotearoa. This means a warming climate will likely lead to higher wasp numbers and increased ecological and economic impacts.

There are a range of other invertebrate pests that may become more problematic in natural systems, plantation forests and agricultural and horticultural settings as winters warm. This includes rising numbers of parasites of sheep and cattle, more insect pests in plantation forests, increased risk of overwintering of the Queensland fruit fly and bigger range sizes for mosquitoes and ant and cattle ticks.

Shrinking alpine refuge

New invasive plant species from subtropical regions may also be able to establish or expand their ranges and shift into the alpine zone.

Similarly, the upward expansion of invasive mammals will reduce the availability of refuge areas for native birds, including the endangered rock wren.

Known as “thermal squeeze”, the movement of rats and stoats to higher elevations reduces the availability of safe spaces for large alpine birds such as the kea, exacerbating the risk of extinction.

The alpine zone is especially vulnerable to winter warming because plants and animals living there are highly adapted to the specific environmental conditions and are often poorly prepared for invasive predators or competitors.

Horticultural winners and losers

In the horticulture industry, cold winter nights are important as a trigger for spring flowering. Economically important fruits such as apples, avocados and kiwifruit may not flower well and have poor-quality fruit under future climates.

Potatoes and onions are also sensitive to warming conditions because heat stress reduces the quality of tubers and produces smaller bulbs, causing lower yields of both crops.

Plant breeding and gene technologies offer opportunities to develop fruits and vegetables that are better prepared for a warmer world.

And there is some good news in other areas, including that flea infestations are predicted to decline in regions where warming is associated with drying. There may also be opportunities for the establishment of new crops, such as bananas.

As the climate continues to warm, there is more to learn about the impacts and options for adaptation in Aotearoa. Research needs to focus on finding solutions for native species and primary industries because healthy ecosystems are essential for a healthy economy and thriving communities.

Cate Macinnis-Ng, Professor in Biological Sciences, University of Auckland, Waipapa Taumata Rau

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

Most of us think of espresso as a hot, high-pressure ritual. Finely ground coffee goes into a machine, boiling water is forced through it, and in about 30 seconds we get a concentrated shot with crema, aroma, bitterness, body and caffeine.

As someone from Colombia, I like to think coffee is in my blood – and I’m proud to come from a country known for producing some of the best coffee beans in the world.

So perhaps that’s why I have spent a lot of time in my laboratory with my team asking a simple question: does espresso really need hot water?

Our new research suggests the answer may be no.

Low energy, full strength

We have developed what we call an ultrasonic espresso: a room-temperature brewing process that uses high-frequency sound waves to extract the flavour, oils, aroma and caffeine from coffee grounds. The result is an espresso-strength coffee made in under three minutes, but needing far less energy than the conventional method.

Saving up to 75% of energy by not heating the water is a minor benefit for home users or small coffee shops. But for companies making ready-to-drink coffee products at industrial scale, it could be very significant indeed.

A concentrated room-temperature coffee could be used directly in bottled drinks, milk-based beverages or cold coffee products. It can also be shipped as a concentrate and diluted later. This would reduce not only energy use, but potentially processing time as well.

Ultrasound replaces heat

The key to the new process is ultrasound. These are sound waves above the range of human hearing.

In our system, a small metal device called a transducer presses against the side of a traditional espresso basket and makes it vibrate rapidly. Those vibrations move through the water and coffee grounds.

This creates a phenomenon known as acoustic cavitation. Tiny bubbles form and collapse in the liquid.

When these bubbles collapse near coffee particles, they produce microscopic jets and forces that act a little like scrubbing brushes. They pit and fracture the surface of the coffee grounds, helping flavour compounds, oils and caffeine move into the water much faster than they normally would at room temperature.

In other words, ultrasound helps us replace heat with mechanical energy.

Water, grind and time

This is not the same as cold brew. Cold brew is usually made by steeping coffee in cold water for 12 to 24 hours. It tends to be smooth, mellow and much less concentrated than espresso. In earlier work, we used ultrasound to speed up cold brew dramatically.

But the challenge in this project was different: could we produce something with the strength, body and intensity of espresso, without heating the water?

To do that, we adjusted several variables. Brew ratio was one of the most important: how much water we used for each gram of coffee. Too much water and the drink becomes diluted; too little and extraction becomes difficult.

Grind size also mattered. Finer grounds allowed us to extract flavour more rapidly. Finally, we tested how long the ultrasound should be applied. We found the sweet spot was about two-and-a-half to three minutes.

The taste test

Of course, making a concentrated coffee in the laboratory is one thing. The real test is whether people want to drink it.

So we ran a blind evaluation with around 100 regular coffee drinkers. They were not trained judges; they were everyday consumers who drink coffee at least once a week.

We served them four coffees in identical cups: traditional espresso, ultrasound-brewed espresso, traditional filter coffee and ultrasound-brewed filter coffee. All were freshly prepared, cooled to the same temperature and presented in random order.

For the espresso samples, participants could not reliably tell the traditional and ultrasonic versions apart. There were no significant differences in aroma, flavour, bitterness or overall liking. For filter coffee, the ultrasound version was actually preferred overall, with participants rating its bitterness more pleasantly.

Those results show espresso may not need to begin with hot water after all. By using sound waves to shake the coffee grounds, we were able to create the same richness, body and intensity, but with far less energy.

Francisco Trujillo, Senior Lecturer, School of Chemical Engineering, UNSW Sydney

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

We’re used to a lot of different natural things falling out of the sky. These can include snow, rain, and sometimes even frogs (yes, really). All of these relate to weather phenomena.

Far more exotic things fall from the sky that are not related to weather. Earth is pelted by about 14 tons of micrometeorites each day. And larger meteorite falls also happen daily, which are visible as fireballs that streak across the night sky.

When an asteroid collides with Earth, it can trigger even stranger debris. Tektites are glassy droplets that form by melting during a meteorite impact, and are then ejected hundreds to thousands of kilometres away from the impact site. The Australasian tektite field that formed some 790,000 years ago from an unknown impact and might cover 10–30% of Earth’s surface is the most famous example.

In a new study published in the journal Meteoritics and Planetary Science, we describe the discovery of a previously unknown 4km-diameter meteorite impact crater in the Eastern Goldfields of Western Australia.

A gold band points the way

The impact site is near the town of Ora Banda (Spanish for “gold band”), a historic gold mining district about 50km north of Kalgoorlie.

For now we’ve named the site the “Ora Banda impact structure”, given its proximity to the historic mining district. However, the region has a much longer history of First Nations culture, and we’re currently working with collaborators at the Goldfields Aboriginal Language Centre on establishing an Indigenous name for the site.

The impact site is interesting for a number of reasons. Ora Banda is one of the few impact craters on Earth whose target rocks – meaning, all rocks in the area affected by the impact – are ancient greenstones, which are metamorphosed volcanic rocks like basalt.

Greenstones are valuable to the economy of Australia because in some places they contain gold. The Ora Banda impact was accidentally discovered during exploration drilling for gold.

The ‘smoking gun’ evidence for impact

If you find a site you suspect might be an impact crater, the scientific process to confirm that’s indeed the case involves documenting what’s known as diagnostic evidence.

Diagnostic impact evidence – the “smoking gun” of an impact – is that which is found nowhere else. It can include either evidence of the space rock itself, or unique high-pressure shock wave damage in the target rocks.

The first evidence for impact we found at Ora Banda was shatter cones – distinctive conical features in rocks that record the passage of the shock wave. We found a few shatter cones in rubbly outcrops at the surface, and we also found some in the drill cores.

The discovery of shatter cones nailed it – we knew then this spot had to be an ancient impact site.

However, we set out to look for more evidence in order to further support our new impact hypothesis and learn more about the event. So, we went back to the cores.

Unusual rocks

The Ora Banda drill cores contained a range of different rock types. At the top was a sequence of clay-rich sediments – these washed into the crater after it formed. At the bottom were rocks that had a different story to tell: impact breccias.

Breccia is a name for any rock that’s been broken up into smaller fragments and has a matrix of smaller particles that “glue” it all together. Breccias are commonly found at impact craters, because the high-energy shock waves can cause rocks to instantly shatter.

Not surprisingly, there are different types of impact breccias, depending on what they contain.

A breccia is “monomict” if it consists of just one rock type, or “polymict” if it contains pieces of different rocks. Polymict breccias provide strong evidence of mixing, as if the rocks were thrown together in a blender. Both breccia types occur in the Ora Banda cores.

If breccia contains glassy melt particles along with other bits of rock, we call that “suevite”. The glassy bits provide key evidence for an even stranger part of the impact process.

They hint that molten material was thrown up into the sky when the meteorite smashed into Earth. While flying in the air, the molten particles turned to glass before landing back into the newly formed crater, resulting in a layer of suevite breccia.

But that’s not all. We found two additional types of microscopic “smoking gun” impact evidence in the breccia.

The first was shocked quartz grains, deformed in a way that’s unique to meteorite impacts. The second was meteorite residue in the glass. This happens because the meteorite vaporises and partly dissolves within the glassy melt particles.

With the discovery of shatter cones, shocked quartz, and extra-terrestrial meteorite residue, our hypothesis that the Ora Banda structure is an impact crater was confirmed.

Raining gold?

Glass and shocked minerals wasn’t all we found in the Ora Banda breccias. Some also contained small nuggets of gold.

This means that during the impact event, when all the shocked rock fragments and glass were thrown up into the sky, gold particles were also raining back down onto the surface, into the newly formed breccia deposits. That’s not something typically found in impact craters, and it shows how unique this geologic setting is.

With Ora Banda, and the recently discovered Ilkurlka and Miralga structures, there are now 34 confirmed meteorite impact craters across Australia. They range in age from a few thousand years old, to the 2.2 billion-year-old Yarrabubba structure.

Some, like the iconic Wolfe Creek (Kandimalal) crater, are youthful and well preserved. Most others, including Ora Banda, are older and eroded to the point that a circular crater is no longer visible.

Aaron J. Cavosie, Senior Lecturer, School of Earth and Planetary Sciences, Curtin University and Raiza R. Quintero, Assistant Professor, Department of Geology, University of Puerto Rico - Mayagüez

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

If you’ve ever stood on a Victorian beach and felt the wind from the Southern Ocean, you’ll know this is not a gentle force. Whipped up across thousands of kilometres of cold ocean, these winds are relentless and powerful.

More than that – they’re one of Australia’s most valuable untapped sources of energy. Australia has many windfarms, but all of them have been built on land.

The stronger, more reliable winds blowing over oceans now turn truly enormous turbines in nations from Denmark to China. Offshore wind would work particularly well in Victoria. The state government wants large windfarms built out at sea to replace the remaining coal plants.

But will these strong winds keep blowing as reliably under climate change? Our recent research is reassuring. Despite small drops in wind strength, the winds will remain strong and reliable over the next 30-50 years.

What’s so good about offshore wind?

Offshore wind farms produce power more reliably than onshore wind or solar. They can produce a great deal of power and require minimal land. This is why offshore wind has been seen as a good fit for Australia.

Coupled with big batteries and transmission lines, offshore wind could contribute significantly to the energy transition.

Victoria has most at stake. For decades it has relied on brown coal and gas. But its gas supplies are depleting fast and ageing coal plants in the Gippsland region will not be replaced with more coal. Instead, the state wants to tap Gippsland’s offshore wind resources, which rank among the world’s best.

Despite the interest, the offshore wind sector has been slow to start. Political and economic headwinds have led some projects to be cancelled. But the sector looks set to finally begin in August, when Victoria will host the nation’s first offshore auction with a goal of securing 2 gigawatts of capacity.

Victoria is not alone. Offshore wind zones have been declared along Australia’s entire southern and western coastline, including Victoria, South Australia, Tasmania and parts of New South Wales and Western Australia.

Will the winds stay strong?

As the climate changes, wind patterns are likely to change too.

The powerful westerly winds of the Southern Ocean are forecast to be gradually pushed closer to Antarctica. Wind speeds across southern mainland Australia could drop by up to 5% by the end of the century.

If wind speeds drop too much, it could pose a problem for offshore wind. Weaker winds would mean less electricity can be generated, potentially making projects less viable and slowing the energy transition.

An offshore windfarm commissioned today will operate for 25–30 years. That means it will still be operating mid-century, when climate change is likely to have intensified.

To find out what climate change will mean for offshore wind, we worked with climate scientists and offshore wind researchers to simulate winds 30-50 years from now using seven high-resolution regional climate models.

We projected future wind speeds at the ocean surface and offshore wind energy production across Australia’s existing offshore wind zones under two scenarios – ambitious climate action limiting global warming to around 1.8°C and continued fossil fuel dependence driving warming to roughly 3.6°C by 2100.

We validated our projections against the best available records of historical wind speeds, which date back several decades. This is because it’s not just about whether wind speeds change, but whether they will change more than the natural variability offshore wind farms can already cope with.

What we found was broadly reassuring. Yes, the winds are likely to weaken over the next 30 to 50 years. But the changes are minor, falling 0.1% to 2.6% on average. That’s within the bounds of natural variability. Unlike projections of future rainfall or temperature, our findings hold across both emissions scenarios. This suggests offshore winds will remain strong and reliable overall.

While reassuring, one area is likely to see a larger drop. Under the high emissions scenario, wind speeds are likely to fall up to 20% over winter in Western Australia’s offshore wind zones near Bunbury.

Good news for offshore wind?

It’s good news that average wind speeds across Australia’s offshore wind zones are not likely to change significantly.

Our research is not the whole story, however. We didn’t model whether extreme winds or strong swell conditions will become more likely. These events can stop windfarms from operating, damage infrastructure and shorten the window of time when turbines can be installed and maintained.

To give offshore wind developers full certainty, it will be important to study what climate change will do to these extreme events.

Alberto Meucci, Research Fellow in Oceanography, The University of Melbourne; Guisela Grossmann-Matheson, Research Fellow in Oceanography, The University of Melbourne, and Shiaohuey Chow, Associate Professor in Geotechnical Engineering, The University of Melbourne

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

Following the devastating Northern Rivers floods in New South Wales in 2022, roughly 14,000 truckloads of water-damaged materials were sent to landfill.

The flood exposed many things, including our unimaginative approach to managing waste. As immediate recovery moved into reconstruction, we saw an opportunity to manage this flood-damaged material differently.

We proposed an alternative to traditional house demolition. It was piloted on two flood-damaged houses in Lismore, using a “circular” model that could reuse materials and eliminate waste.

As well offering potential economic benefits for the local community, our report found it had considerable social and environmental value.

Why did homes get demolished?

In the aftermath of the floods, many NSW homes were significantly damaged and still lay in the path of future floods. In response, the NSW government introduced a buy-back scheme for eligible homes in flood-prone areas.

Part of this program involved demolishing homes, with the materials discarded in landfill or used for low-value recycling, such as woodchipping and burning. Yet the homes contained valuable materials, such as hardwood timbers.

Losing these homes was traumatic for the local community and an unnecessary loss of valuable resources. So the NSW Reconstruction Authority, Living Lab Northern Rivers, and the University of Technology Sydney (UTS) explored how to recover a material that is extremely difficult to source today – old growth timber.

The colonial hunger for hardwood

The first wave of European colonisation of the Northern Rivers included groups known as “cedar getters”. These timber cutters arrived in search of highly-prized rainforest hardwoods.

Much of this timber was transported to Australian cities or as far away as Europe. It was also used to construct buildings and homes for local communities.

Premium old growth timbers extracted from the area included red cedar (Toona ciliata), spotted gum (Corymbia maculata), tallowwood (Eucalyptus microcorys), rosewood (Didymocheton fraserianus) and blackbutt (Eucalyptus pilularis).

This is not your ordinary hardware-variety timber. Prized hardwood rainforest timber is dense, strong, durable and resistant to rot and insects.

The circular timber project

In early 2024, the Circular Timber project developed an alternative to traditional demolition, which offers very little opportunity for recovering materials.

The current system for demolishing homes is this: large-scale machines level structures and excavators scoop materials into dump trucks, which transport them to distant landfill. Sometimes, materials are recovered, but the vast majority are broken into small pieces, trucked away and buried.

We wanted to establish a “circular” system that reused materials and eliminated waste. This cannot be achieved by a single entity – multiple partners needed to collaborate. In this case, the local community, educators, businesses and government agencies collaborated to establish a pilot where timber from uninhabitable homes could be recovered and reused.

The local community was invited to make prototypes as proof that these premium timbers could be salvaged into new objects. Buy-in from the community was immediate – the materials in these homes represented a link to the region’s history and culture.

Two homes acquired by the government authority were deconstructed, with their recovered materials made available to local timber makers, builders, artists, architects and designers. The salvaged timber was transformed into a dining table, a community shed, and other designed objects.

How it happened

Moving from home demolition to deconstruction represented a significant challenge. There are Australian standards for demolishing a building, but no guidelines for deconstructing exist (yet).

This project developed a considered approach to dismantling the homes. Care was taken in site preparation, materials identification and disassembly to ensure as much of the timber was recovered as possible.

Although deconstructing, recovering and reusing house materials requires more time, there were significant local and global benefits. For example, salvaging timber reduces carbon emissions, significantly reduces waste sent to landfill, and has a smaller carbon footprint than using virgin timber.

There are also economic and social benefits. This was a Northern Rivers community with a long history of seeing lives turned upside down by catastrophic floods. They responded positively to retaining the physical, cultural, and historical value of the past built into these homes.

Homes hold many values

Between 2019 and 2025, there were 214,483 approvals granted nationwide for knock-down-and-rebuild applications in Australia, with the management of waste material left to the discretion of the owner and demolition contractor.

A standard Australian house can include salvageable materials such as hardwood timber, premium timbers, pressed metal ceilings or Federation red bricks.

Shifting our approach from demolition to deconstruction could open up new opportunities. Not only could it create jobs, but it could reduce the need for virgin materials and protect our environment.

This project reminds us that value should not only be assessed in economic terms but also in relation to our environment and communities. This program showed deconstructing homes can be embraced as a way to transform waste into a valuable resource.

Berto Pandolfo, Associate Professor, Product Design, University of Technology Sydney; Angelique Milojevic, Design Researcher, University of Technology Sydney, and Dan Etheridge, Director, The Living Lab Northern Rivers, Office of Pro Vice Chancellor (Research and Education Impact), Southern Cross University

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

It may seem like it’s impossible to find a car park on the street.

As a recent Grattan Institute report makes clear, Australia actually has an oversupply of parking, both on streets and in parking lots. Across five of the state capitals, most postcodes have more on-street spaces than there are registered cars.

That’s great for drivers, given most on-street parking outside the inner city is free and has no time limit. Many spaces are used by locals with a driveway or garage who find it more convenient to park on the street.

The problem is, abundant street parking comes at a cost. Streets jammed with parked cars look bad – and remove space for bikes, e-bikes and scooters.

Is it too late to change course? No.

The rise and rise of kerbside parking

If you look back at the street designs by 19th-century planning pioneers, you immediately notice something very different from today’s city streets.

Back then, there was no kerbside parking. Streets were largely shared spaces, where walkers, horse coaches, trams and early bicycles mingled. Of course, this was when motor vehicles were just emerging.

As car ownership surged in the 1920s and ‘30s, city centres began to struggle with parking shortages, double parking and endless cruising for spaces. The problem was summed up by Nebraska journalist Henry Allen Brainerd in a letter to his city newspaper:

What a pity that the builders of large business blocks could not have looked ahead at the time of building and seen the need for parking space in the larger cities of the world.

Since then, many cities around the world have heeded that advice, requiring parking spaces to be provided everywhere – along city streets, in suburbs, under apartment blocks and in parking lots.

What’s wrong with kerbside parking?

Many people see kerbside parking as a simple fact of life. But it was a choice, and it comes with real costs.

For one, parked cars look bad. A pretty street loses appeal if there are endless lines of parked cars. There’s a reason real estate ads don’t include cars. People find it stressful or boring to be in monotonous streetscapes characterised by heavy traffic and parking.

Road space is limited. Drivers are using a public road to park their private cars.

Worse still, kerbside parking makes it much harder for other types of transport to share the road. In recent years, there’s been huge growth in micromobility – think bikes, e-bikes and scooters.

But the road space available hasn’t changed much. Too often, riders are forced onto skinny bike lanes that end abruptly, or have to try and ride in the narrow space between parked cars and moving vehicles.

As micromobility booms, the pressure on scarce road space will only intensify as riders demand wider segregated paths. The only way this could happen in densely populated areas is if there was less kerbside parking.

Could we really reduce kerbside parking?

What would happen if authorities banned on-street parking? Given the oversupply of parking, most drivers would be able to park off-street, such as at shopping centres, offices and parking lots. These would need better sharing arrangements.

With road space freed up, it would be possible to make many streets much more pleasant – and include safe two-way paths for riders.

In areas where these lanes aren’t needed, the freed-up space could be used for trees and plants to help cool cities and soak up rain. Other options include EV charging stations and expanding outdoor dining, as many areas did during the COVID years.

In practice, a ban on kerbside parking couldn’t be universal. Some spaces would have to be reserved for people with disabilities, emergency services, deliveries, ride-hailing and car-sharing.

But would it be political suicide?

There’s almost always a backlash when authorities try to wind back kerbside parking.

Resistance usually comes from drivers, residents and business owners, who worry that less on-street parking will lead to more traffic, less business and even a drop in property prices.

The opposite is true. When high streets are made more friendly to bikes and other forms of micromobility, businesses generally make more money, not less, and property values can go up. People who prefer driving or have no alternative also benefit from less traffic, making it more likely they can visit the business.

Overseas examples show it can be done

In many European nations, authorities have worked to make streets less centred on cars and parking.

Established models of reducing car parking include Woonerven (living streets) and Fietsstraten (cycling streets) in the Netherlands, as well as car-free or car-lite neighbourhoods such as Vauban in Germany and Hammarby Sjöstad in Sweden. If cars are permitted at all, they are treated as guests.

Even in the car-friendly United States, there are examples such as as Culdesac Tempe near Phoenix, a car-free development without kerbside or household parking. My colleagues and I have dubbed this “Robin Hood planning” – taking from cars and giving to people.

If this is possible in the US – the land of automobility – it should be possible in Australia.

Dorina Pojani, Associate Professor in Urban Planning, The University of Queensland

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

Around 13,000 years ago, as the world was emerging from the grip of the last ice age, much of the North Atlantic region plunged back into near-glacial conditions.

Sea ice expanded across the North Atlantic, reaching as far south as the Shetland Islands. Glaciers began to regrow in the Scottish Highlands, while winter temperatures across Europe and North America plummeted. Yet off the coast of Atlantic Canada, the ocean did the opposite.

In our new study, published in the journal Nature Communications, we found evidence that waters off Nova Scotia, Canada, warmed as the Gulf Stream shifted hundreds of kilometres northward, while deep circulation also changed.

It is the first direct evidence that this vital current responded in such a way during a period of abrupt climate change that rearranged Atlantic Ocean circulation.

The finding lends support to the climate models that predict a similar northward shift in the future if the Atlantic Meridional Overturning Circulation (Amoc) weakens – a trend that has probably already begun.

Why the Gulf Stream matters

The Gulf Stream transports warm tropical waters northwards along the eastern coast of North America before turning north-east towards Europe. In doing so, it forms part of the Amoc, a vast system of ocean currents that redistributes heat, nutrients and carbon around the Atlantic Ocean. Consequently, the Amoc plays a major role in regulating the climate. In particular, the northern arm of the Gulf Stream helps keep western Europe much milder than other regions at similar latitudes.

Scientists are increasingly concerned about the future of this circulation system. As the climate warms and extra freshwater (from melting ice) enters the North Atlantic, surface waters become less dense and therefore less able to sink. Most climate models project that these changes weaken the Amoc. Observations suggest that this weakening has already begun, but it is predicted to weaken much more as the 21st century progresses. However, direct evidence showing how the system responds to such major disruptions remains relatively limited.

To answer that question, paleoceanographers like us turn to the past.

A natural experiment from the end of the last ice age

The Younger Dryas was one of the most dramatic episodes of abrupt climate change in Earth’s recent history. As the planet emerged from the last ice age, warming trends across much of the North Atlantic region abruptly reversed. European summer temperatures declined by around 4°C–8°C in less than a century, while Greenland cooled by up to 10°C within just a few decades. The effects rippled far beyond the North Atlantic, weakening monsoon systems across Africa and Asia.

To understand how the ocean responded, we analysed sediment extracted from the seabed off Nova Scotia. Microscopic fossil shells and sediment grains preserved within this marine mud can reveal what the sea would have been like at the time it formed. We then reconstructed changes in both surface and deep Atlantic circulation before, during, and after the Younger Dryas.

An unexpected warming signal

What we found surprised us. While Greenland and much of the subpolar North Atlantic cooled rapidly, waters off Atlantic Canada warmed instead, by as much as 4°C–5°C.

The most likely explanation is that the Gulf Stream migrated northwards, bringing warm subtropical waters closer to the Canadian coastline.

Previous climate-model simulations had predicted that a weakening of one of the Amoc’s deep currents could trigger exactly this response. Until now, however, there had been little direct geological evidence that it had happened before.

Our study provides real-world evidence for a process that climate models have long proposed. That matters because it shows that large reorganisations of Atlantic circulation are not just theoretical possibilities – they have happened before.

What can the past tell us about the future?

No past climate event is a perfect analogue for modern climate change. The Younger Dryas occurred under very different conditions from today. Massive ice sheets still covered much of Canada and Scandinavia, and the sea level was tens of metres lower than at present.

Nevertheless, the physical links connecting the different components of the North Atlantic circulation system are likely to be the same.

Our study does not suggest that the Amoc completely collapsed during the Younger Dryas, nor does it tell us whether such a collapse is likely in the future. Instead, it reveals a more nuanced picture in which various components of the North Atlantic circulation system changed in different ways. Rather than producing a uniform response, this reorganisation created a patchwork of warming and cooling across the North Atlantic.

Similar patterns have also emerged over the last 150 years, with a relative “warming hole” developing in the ocean south of Greenland while regions closer to the Gulf Stream have warmed more rapidly. Our findings provide real-world evidence that these contrasting patterns are closely linked to changes in ocean circulation.

Looking to the future, scientists are concerned that continued human-caused warming could trigger major changes in North Atlantic circulation, leading to shifts in ocean temperature patterns, which would disrupt weather and climate across the globe. Examining how the Atlantic behaved 13,000 years ago can help us recognise the warning signs of major changes before they happen again.

Critically, our study suggests that such reorganisations can unfold over about a century, with individual components of the circulation changing within just a few decades – within a human lifetime.

By showing how different parts of the Atlantic circulation interacted during a past episode of abrupt climate change, our findings provide an important benchmark for testing climate models. The deeper understanding we have gained into how the interconnected Atlantic system behaves will also help us with the very challenging task of developing early-warning systems for future circulation changes and potential climate tipping points.

Alice Carter-Champion, Researcher, Paleoceanography, Royal Holloway, University of London; Fangjingcheng Zhu, PhD Candidate, Paleoceanography, University of Southampton, and Jack Wharton, Postdoctoral Research Fellow in Paleoceanography, UCL

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