Climate Change - Australia's difficult future unless increased action is taken

Is this Australia’s climate wake-up call? Official report reveals a hotter, harder future if we don’t act now

Andrew B. Watkins, Monash University; Lucas Walsh, Monash University, and Tas van Ommen, University of Tasmania

Climate shocks threaten to devastate communities, overwhelm emergency services and strain health, housing, food and energy systems according to a federal government assessment released today.

The report, Australia’s first National Climate Risk Assessment, confirms the devastating consequences of climate change have arrived. It also reveals the worsening effects of extreme heat, fires, floods, droughts, marine heatwaves and coastal inundation in coming decades.

The sobering assessment is a major step forward in Australia’s understanding of who and what is in harm’s way from climate change. It is also a national call to action. The sooner Australia mitigates and adapts, the safer and more resilient we will be.

Australia’s climate risk revealed

The assessment involved more than 250 climate experts, including the authors of this article, and contributions from more than 2,000 specialists. It was also informed by data and modelling from the Australian Climate Service, CSIRO, Bureau of Meteorology, the Australia Bureau of Statistics and Geoscience Australia, among other major institutions.

The report provides the vital evidence base to inform Australia’s first National Adaptation Plan, also released today.

Earth has already warmed by 1.2°C since pre-industrial times, and remains on track for 2.7°C by the end of the century if no action is taken. The assessment considers the impacts on Australia at 1.5°C, 2°C and 3°C of global warming.

The risks to Australia are assessed under eight key systems, as we outline below.

Graphic showing climate risks to Australia’s key systems. National Climate Risk Assessment

1. Health and social support

Climate hazards will severely impact physical and mental health. The most vulnerable communities include Aboriginal and Torres Strait Islander people, the elderly, the very young and those with pre-existing health conditions, as well as outdoor workers.

At 3°C global warming, heat-related deaths increase by 444% for Sydney and 423% for Darwin, compared to current conditions.

Deaths from increased disease transmission are expected to rise. Vector borne diseases such as malaria and dengue fever may spread in the tropics.

Attracting health care workers to remote areas will be increasingly hard, and services will be strained by rising demand and disrupted supply chains.

2. Communities

Coastal, regional and remote communities face very high to severe risk.

More than 1.5 million people in coastal communities could be exposed to sea level rise by 2050, increasing to more than 3 million people by 2090.

Communities within 10km of soft shorelines will be especially vulnerable to erosion, inundation and infrastructure damage.

Extreme weather events – including heatwaves, bushfires, flooding and tropical cyclones – will intensify safety and security risks, especially in Northern Australia.

Compounding hazards are expected to erode community resilience and social cohesion. Water supplies in many areas will be threatened. Economic costs will escalate and people may be forced to migrate away from some areas.

3. Defence and national security

Climate risk to defence and national security is expected to be very high to severe by 2050. This system includes emergency management and volunteers.

Defence, emergency and security services will be increasingly stretched when hazards occur concurrently or consecutively.

If the Australian Defence Force continues to be asked to respond to domestic disasters, it will detract from its primary objective of defending Australia. At the same time, climate impacts will cause instability in our region and beyond.

Repeated disasters and social disruptions are likely to erode volunteer capacity. Increasing demands on emergency management personnel and volunteers will intensify and may affect their physical and mental wellbeing.

4. Economy and finance

Risks to the economy, trade and finance is expected to be very high by 2050. Projected disaster costs could total A$40.3 billion every year by 2050, even at 1.5°C.

Losses in labour productivity due to climate and weather extremes could reduce economic output by up to $423 billion by 2063. Between 700,000 and 2.7 million working days would be lost to heatwaves each year by 2061.

Extreme weather will lead to property damage and loss of homes, particularly in coastal areas. Loss on property values are estimated to reach A$611 billion by 2050. Insurance may become unaffordable in exposed areas, putting many financially vulnerable people at further risk.

Coupled with increased prices for essential goods, living costs will rise, straining household budgets.

The economy could experience financial shocks, leading to broader economic impacts which especially affect disadvantaged communities.

5. Natural environment

Risk to the natural environment is expected to be severe by 2050.

Important ecosystems and species will be lost by the middle of the century. At 3°C warming, species will be forced to move, adapt to the new conditions or die out. Some 40% to 70% of native plant species are at risk.

Ocean heatwaves and rising acidity, as well as changes to ocean currents, will massively alter the marine ecosystems around Australia and Antarctica. Coral bleaching in the east and west will occur more frequently and recovery will take longer.

Ocean warming and acidification also degrades macroalgae forests (such as kelp) and seagrasses. Freshwater ecosystems will be further strained by rainfall changes and more frequent droughts.

Loss of biodiversity will threaten food security, cultural values and public health. The changes will disrupt the cultural practices of Aboriginal and Torres Strait Islander peoples and their connection to Country.

6. Infrastructure and the built environment

By 2050, the climate risk to infrastructure and built environment is expected to be high or very high.

Climate risks will push some infrastructure beyond its engineering limits, causing disruption, damage and in some cases, destruction. This will interrupt businesses and households across multiple states.

Extreme heat and fires, as well as storms and winds, will increasingly threaten energy infrastructure, potentially causing severe and prolonged disruptions.

Transport and supply chains will be hit. Water infrastructure will be threatened by both drought and extreme rainfall. Telecommunications infrastructure will remain at high risk, particularly in coastal areas.

The number of houses at high risk may double by 2100. Modelling of extreme wind shows increasing housing stock loss in coastal and hinterland regions, particularly in Queensland, Western Australia and the Northern Territory.

7. Primary industries and food systems

By 2050, risks to the primary industries and food systems will be high to very high. This increases food security risks nationwide.

Variable rainfall and extreme heat will challenge agriculture, reducing soil moisture and crop yields. Farming communities will face water security threats.

Hotter climates and increased fire-weather risks threaten forestry operations. Fisheries and aquaculture are likely to decline in productivity due to increased marine temperatures, ocean acidity and storm activity.

The livestock sector will face increased heat stress across a greater area. At 3ºC warming, more than 61% of Australia will experience at least 150 days a year above the heat-stress threshold for European beef cattle.

Biosecurity pressures will increase. Rainfall changes and hotter temperatures are expected to help spread of pests and diseases.

8. Aboriginal and Torres Strait Islander Peoples

As part of the assessment, Aboriginal and Torres Strait Islander peoples identified seven additional nationally significant climate risks:

• self-determination
• land, sea and Country
• cultural knowledges
• health, wellbeing and identity
• economic participation and social and cultural economic development
• water and food security
• remote and rural communities.

As the report notes, climate change is likely to disproportionately impact Aboriginal and Torres Strait Islander peoples in terms of ways of life, culture, health and wellbeing as well as food and water security and livelihoods. It also notes Aboriginal and Torres Strait Islander peoples “have experience, knowledge and practices that can support adaptation to climate change”.

Doing more. Doing better.

The assessment poses hard questions about how climate change will affect every system vital to Australia.

Ideally, such an assessment would be carried out every five years and be mandated by legislation.

Future assessments should comprehensively examine global impacts and their flow-ons to Australia. As the COVID pandemic showed, Australia is part of a global system when it comes to human health and supply chains. Defence, trade and finance all are international by nature. And climate change refugees from the South Pacific are already arriving.

The assessment makes clear that current efforts to curb and adapt to climate change will not prevent significant harm to Australia and our way of life. We must do better – and do it quickly.

Young people, and unborn generations, can and will hold us all to account on our progress from today.

Andrew B. Watkins, Associate Research Scientist in Climate Science, Monash University; Lucas Walsh, Professor of Education Policy and Practice, Youth Studies, Monash University, and Tas van Ommen, Adjunct Professor in Climate Science, University of Tasmania

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

Climate Change - Heatwaves lead to faster ageing

                                                                                             Shutterstock

The invisible effects of climate change via the increasing number of heat waves are more profound than many people may have imagined from trends over the past couple of decades. Heat waves in general are a well known health risk through the effects of dehydration, loss of body mass and organ stress. The evidence is now building that heat waves increase the ageing process itself.

A long-term study of 24,922 people in Taiwan, published in Nature Climate Change in August this year, has found that a moderate increase in cumulative heatwave exposure increases a person's biological age "...to an extent comparable to regular smoking or alcohol consumption. The more extreme-heat events that people were exposed to, the more their organs aged".

To reach this conclusion, the researchers analysed data from medical examinations between the years 2008 to 2022 during which time Taiwan experienced around 30 heatwaves. The definition of 'heatwave' applied was a period of elevated temperature over several days.  The results from several medical tests including assessments of liver, lung, kidney function, blood pressure and inflammation was used to calculate biological age. 

The results from the study found that the more extreme-heat events that people experienced the faster the ageing process that occured. For every extra 1.3°C exposure for a participant, around 0.023 to 0.031 years on average was added to their biological clock.  While the initial numbers may appear small, over time with accumulated effects and across populations, the impact on public health would be meaningful and costly. As increasing heat is a key effect from climate change, this latest research demonstrates the wide range of implications for life on this planet.

Health - the menace of mosquitoes

A warm, wet spring means more mozzies. How to protect yourself from the diseases they spread

Cameron Webb, University of Sydney

Mosquito bites are annoying. They can also have deadly consequences. So what diseases do mosquitoes in Australia carry?

And with warmer weather on its way and rain expected to continue, how can you prepare for the coming mosquito season?

Mosquitoes are deadliest animal

Mosquitoes kill more people than any other animal. Worldwide, more than half a million people die each year from mosquito bites that transmit malaria parasites.

Australia is fortunate to be free of major outbreaks of malaria, though occasional cases do occur.

The most common mosquito-borne disease in Australia is caused by Ross River virus. Around 5,000 cases are reported each year and, while never fatal, the illness can be severely debilitating. Symptoms include fever, rash, joint pain and fatigue.

Mosquito populations fluctuate year by year. A/Prof Cameron Webb (NSW Health Pathology), CC BY-NC-SA

Murray Valley encephalitis virus is responsible for very rare but potentially fatal disease. It’s detected most years in northern Australia.

There has been a resurgence of the virus in southeastern parts of Australia following flooding in recent years. Mosquitoes pick up the virus from waterbirds throughout the Murray Darling Basin before they pass on the pathogen to people. Mosquito and waterbird populations both boom after flooding.

Mosquitoes in some coastal areas of Victoria can also pass on the flesh-eating bacteria that can cause Buruli ulcer.

What about Japanese encephalitis?

Japanese encephalitis virus can cause fever, headaches, vomiting and, in rare cases, death.

Over the summer of 2021-22, there were 45 cases of Japanese encephalitis in southeastern Australia. This virus was never expected to spread so widely. In some parts of Australia, people died due to mosquito bites for the first time in around 50 years.

Scientists and health authorities thought Japanese encephalitis virus would transmit in a similar way to the closely related Murray Valley encephalitis virus, with outbreaks typically occurring after flooding that provided ideal conditions for both mosquitoes and the waterbirds carrying the virus.

But we now know pigs – especially feral pigs – are in the mix too, along with a range of other animals.

With gaps in our understanding of what drives local transmission, predictions of Japanese encephalitis activity are now proving to be less reliable. This makes it hard to work out the threat it may pose this summer.

Last summer, despite the lack of any substantial rainfall, the virus turned up even though mosquito (and waterbird) populations were generally low.

The virus also wasn’t limited to those areas where we’d expect to see it. There is growing evidence it’s made its way to the east coast, with the virus detected in the suburbs of Brisbane.

Ongoing wet weather can provide ideal conditions for mosquitoes. A/Prof Cameron Webb (NSW Health Pathology), CC BY-NC-SA

How will the weather impact mosquitoes this season?

Like all insects, mosquitoes thrive in warmer weather. But they also need water.

It doesn’t really matter if it’s a “wet” or “dry” summer, mosquitoes are always active. But sometimes there are more – lots more.

In most parts of Australia, there is currently no shortage of water. Some regions have had record rainfall this winter, with more on the way.

The Bureau of Meteorology is predicting above-average rainfall through to the end of the year. Once the weather warms up, it could be a “buzzy” start to mosquito season.

This doesn’t mean outbreaks of mosquito-borne disease are inevitable. But we need to be alert to the risks and how best to protect ourselves and family.

Scientists like me trap mosquitoes across Australia each summer to track changes in their abundance, as well as activity of pathogens. A/Prof Cameron Webb (NSW Health Pathology), CC BY-NC-SA

Monitoring mozzies

More rain means a greater risk of mosquito-borne disease. But outbreaks aren’t easy to predict, so surveillance is critical.

Australian state and territory health authorities undertake monitoring of mosquitoes and the pathogens they carry each year. The objective is to provide an early warning of elevated risk of mosquito-borne diseases. This may be due to increased mosquito activity or the detection of mosquito-borne pathogens.

Given the uncertainty around Japanese encephalitis, it’s also important to monitor locations where the virus has not yet been detected.

How to stay safe this spring and summer

There’s a lot you can do to protect yourself and family from mosquito bites and mosquito-borne disease.

A vaccine is available for those at risk of Japanese encephalitis. See your local health professional for advice on accessing the vaccine.

But there aren’t vaccines for the other local mosquito-borne diseases. Nor are there any specific treatments for these diseases. So preventing mosquito bites is the best way to protect yourself.

If you’re outdoors when mosquitoes are active, cover up with long pants, a long-sleeved shirt and covered shoes. Apply an insect repellent containing diethyltoluamide, picaridin, or oil of lemon eucalyptus to all exposed skin.

Skip the stickers, patches and wristbands, as the evidence shows they aren’t a reliable way to prevent bites.

Keep your property free of mosquito breeding grounds, too. Mosquitoes can lay eggs in any container that fills with water: a plant saucer, a bird bath, discarded plastic buckets, bottles or tins. Tip them out each week, cover them up or throw them away.

Cameron Webb, Clinical Associate Professor, School of Medical Science & Sydney Infectious Diseases Institute; Principal Hospital Scientist, University of Sydney

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

Health and exercise - weightlifting and bone density

Does weightlifting improve bone density?

Inti St Clair/Getty

Hunter Bennett, University of South Australia

You may have heard high-impact activity – exercise such as running, jumping, football and basketball – is good at building bone density and strength. But what about when you’re standing still, lifting weights at the gym?

The good news is weight training is great for bone health. But some exercises are more effective than others. Here’s what the science says.

What is bone density?

Bone density, also known as bone mineral density, is essentially a measure of how many minerals (such as calcium and phosphorus) are packed into your bones.

It gives you an indication of how solid your bones are, which is important because denser bones are generally less likely to break.

However, bone density is not quite the same as bone strength.

Bones also rely on a range of other compounds (such as collagen) to provide support and structure. So, even dense bones can become brittle if they are lacking these key structural components.

However, bone mineral density (measured with a bone scan) is still considered one of the best indicators of bone health because it is strongly linked to fracture risk.

While there is likely a genetic component to bone health, your daily choices can have a big impact.

What affects your bone health?

Research shows a few factors can influence how strong and dense your bones are:

Getting older: As we age, our bone mineral density tends to decrease. This decline is generally greater in women after menopause, but it occurs in everyone.

Nutrition: Eating calcium-rich foods – dairy in particular, but also many vegetables, nuts, legumes, eggs and meat – has been shown to have a small impact on bone density (although the extent to which this reduces fracture risk is unclear).

Exposure to sun: Sunlight helps your body make vitamin D, which helps you absorb calcium, and has been linked to better bone density.

Exercise: It is well established that people who do high-impact and high-load exercise (such as sprinting and weight training) tend to have denser and stronger bones than those who don’t.

Smoking: Older people who smoke tend to have lower bone density than those who don’t smoke.

Why does movement improve bone density?

In the same way that your muscles get stronger when you expose them to stress, your bones get stronger when they’re asked to handle more load. This is why exercise is so important for bone health – because it tells your bones to adapt and become stronger.

Many of us know that people at risk for bone loss – post-menopausal women and older adults – should be focused on exercising for bone health.

However, everyone can benefit from targeted exercise, and it’s arguably just as important to prevent declines in bone health.

In fact, whether you are male or female, the younger you start, the more likely you are to have denser bones into your older life. This is crucial for long-term bone health.

Do weights improve bone density?

Yes. One of the most effective exercises for bone health is lifting weights.

When you lift weights, your muscles pull on your bones, sending signals that encourage new bone formation. There is a large body of evidence showing weight training can improve bone density in adults, including in post-menopausal women.

But not all exercises are created equal. For example, some evidence suggests large compound exercises that place more load on the skeleton – such as squats and deadlifts – are particularly effective at increasing density in the spine and hips, two areas prone to fractures.

What type of weight training is best?

Lifting heavier weights is thought to produce better results than lifting lighter ones. This means doing sets of three to eight repetitions using heavy weights is likely to have a greater impact on your bones than doing many repetitions with lighter ones.

Similarly, it takes a long time for your bones to adapt and become denser – usually six months or more. This means for healthy bones, it’s better to integrate weight training into your weekly routine rather than do it in bursts for a few weeks at a time.

Exercises that use body weight, such as yoga and pilates, have many health benefits. However they are unlikely to have a significant impact on bone density, as they tend to put only light stress on your bones.

If you are new to weight training, you might need to start a bit lighter and get used to the movements before adding weight. And if you need help, finding an exercise professional in your local area might be a great first step.

Exercising for bone health is not complex. Just a couple of (heavy) weight training sessions per week can make a big difference.

If you’re concerned you have low bone density, speak to your doctor. They can assess whether you need to go for a scan.

Hunter Bennett, Lecturer in Exercise Science, University of South Australia

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

Environment - Climate Change - Extreme weather and declining tropical birdlife

70 years of data show extreme heat is already wiping out tropical bird populations

DeAgostini/Getty Images

James Watson, The University of Queensland; Maximilian Kotz, Barcelona Supercomputing Center-Centro Nacional de Supercomputación (BSC-CNS), and Tatsuya Amano, The University of Queensland

Human-driven climate change threatens many species, including birds. Most studies on this topic focus on long-term climate trends, such as gradual rises in average temperatures or shifts in rainfall patterns. But extreme weather events are becoming more common and intense, so they warrant further attention.

Our new research shows extreme heat is having a particularly severe effect on tropical birds. We found increased exposure to extreme heat has reduced bird populations in tropical regions by 25–38% since 1950.

This is not just a temporary dip – it’s a long-term, cumulative effect that continues to build as the planet warms.

Our research helps explain why bird numbers are falling even in wild places relatively untouched by humans, such as some very remote protected tropical forests. It underscores the urgent need to reduce greenhouse gas emissions, to conserve the remaining biodiversity.

Digging into huge global datasets

We analysed data from long-term monitoring of more than 3,000 bird populations worldwide between 1950 and 2020. This dataset captures more than 90,000 scientific observations.

Although there are some gaps, the dataset offers an unmatched view of how bird populations have changed over time. Some parts of the world such as western Europe and North America were better represented than others, but all continents were covered.

We matched this bird data with detailed daily weather records from a global climate database that stretches back to 1940. This allowed us to track how bird populations responded to specific changes in daily temperatures and rainfall, including extreme heat.

We also looked at average yearly temperatures, total annual rainfall, and episodes of unusually heavy rainfall.

Using another dataset that reflects human industrial activity over time, we accounted for human pressures such as land development and human population density.

By combining all these sources of data, we created computer models to evaluate how climate factors and human impacts influence bird population growth.

Our research confirmed the work of other climate scientists showing extreme heat events have increased dramatically over the past 70 years, especially near the equator.

Birds in tropical regions are now experiencing dangerously hot days about ten times more often than they did in the past.

Tropical birds have experienced a 10-fold increase in exposure to extreme heat over the past 60 years. Kotz, M. et al. (2025) Nature Ecology & Evolution

What we found: extreme heat is the biggest climate threat to birds

While changes in average temperature and rainfall do affect birds, we found the increasing number of dangerously hot days had the greatest effect – especially in tropical regions.

This is a major concern because tropical birds often have small home ranges and are highly specialised in terms of the habitats and climates they persist in. In many cases tropical birds exist within a small range of heat tolerance.

At temperatures beyond a bird’s limit of endurance, they go into hyperthermia, where their body temperature rises uncontrollably. In this state, birds may adopt a drooped-wing posture to expose more skin for heat loss, hold their beaks open and pant rapidly, spread their feathers, and become lethargic or disoriented. In severe cases, they lose coordination, fall from perches, or even collapse unconscious.

A black-collared barbet (Lybius torquatus) from Botswana. Sergey Dereliev

If they survive the experience, they can suffer long-term damage such as heat-induced organ failure and reduced reproductive capacity. Heat exposure reduces breeding success by lowering adult body condition and reducing time spent foraging – because the birds must rest or seek shade during the hottest hours.

It also causes heat stress in eggs and nestlings. In extreme events, nestlings may die from hyperthermia, or parents may abandon nests to save themselves.

Heat also increases a bird’s demand for water — not because they sweat (birds lack sweat glands) but because they lose water rapidly through evaporative cooling. This happens mainly via panting (respiratory evaporation) and, in some species, gular fluttering (rapid vibration of throat skin to increase airflow), as well as evaporation through the skin. As temperatures climb, these processes accelerate, causing significant dehydration unless birds can drink more frequently or access moister food.

Our study found that across tropical areas, the impact of climate change on birds is perhaps even greater now than the impact of direct human activities such as logging, mining or farming. This is not to say habitat destruction due to these activities is not a serious issue – it clearly is a major concern to tropical biodiversity. But our study highlights the challenges climate change is already bringing to birds in tropical regions.

Extreme heat is bad for birds in more than one way. James Watson, Maximilian Kotz and Tatsuya Amano with icons from Flaticon, design by Canva.

A clear warning

Our research highlights the importance of focusing not just on average climate trends, but also on extreme events. Heatwaves are no longer rare, isolated incidents – they are becoming a regular part of life in many parts of the world.

If climate change continues unchecked, tropical birds – and likely many other animals and plants – will face increasing threats to their survival. Change may be too fast and too extreme for many species to adapt.

And as tropical regions host a huge share of the world’s biodiversity, including nearly half of all bird species, the ripple effects could be far-reaching.

Conservation strategies must take this into account. Protecting habitats from human industrial development remains important, but it’s no longer enough on its own. Proactive action to help species adapt to climate change needs to be part of wildlife protection plans – especially in the tropics.

Ultimately if we are to preserve global biodiversity, slowing down and eventually reversing climate change is essential. That means cutting greenhouse gas emissions, investing in ways to draw down existing carbon dioxide levels, and supporting policies that reduce our impact on the planet. The fate of tropical birds – and countless other species – depends on it.

Tropical bird population declined by one-third since 1980 due to climate change, featuring the study’s lead author Maximilian Kotz (Potsdam Institute for Climate Impact Research)

James Watson, Professor in Conservation Science, School of the Environment, The University of Queensland; Maximilian Kotz, Marie Curie Postdoctoral Research Fellow, Barcelona Supercomputing Center-Centro Nacional de Supercomputación (BSC-CNS), and Tatsuya Amano, Associate Professor, School of the Environment, The University of Queensland

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

Climate change - city heatwaves increase when polluting aerosols are reduced

   aerosol cover in cities                    Shutterstock

In one of the more perverse impacts of environmental monitoring and pollution control, researchers have found that heatwaves increase as harmful aerosol pollution is reduced for the purpose of obtaining cleaner air. The warming has been found to be greater in populated locations where, commensurately, there tends to be more air pollution.

Aerosols cause lower temperatures as they reflect sunlight away from the planet either through altering the cloud composition or as a direct effect. Cleaning up the air and removing aerosols for better human health has resulted ironically in increasing heatwaves and generally warming the climate. Researchers have found that for most of last century, heatwave frequency was slowed despite rising greenhouse gas emissions. This changed from 2005 as declines in polluting aerosols became more apparent. A related issue is that aerosol pollution may have masked up to half the warming effect of greenhouse gas emissions up till now. The net impact has been that aerosol reduction has added heatwaves across the planet by approximately two days per decade.

The research Article can be accessed at this link: Anthropogenic aerosol changes disproportionately impact the evolution of global heatwave hazard and exposure

Climate Change and Australia's Great Barrier Reef

World’s biggest coral survey confirms sharp decline in Great Barrier Reef after heatwave

Daniela Ceccarelli, Australian Institute of Marine Science; David Wachenfeld, Australian Institute of Marine Science, and Mike Emslie, Australian Institute of Marine Science

Official analysis of 124 reefs on the Great Barrier Reef shows coral cover has dropped sharply after a record-breaking marine heatwave in 2024, prompting grave fears over the trajectory of the natural wonder.

Over the past few years, fast-growing corals had pushed the Great Barrier Reef’s coral cover to record highs. But those corals were known to be extremely vulnerable and one bad summer away from losing those gains.

Our new report by the Australian Institute of Marine Science (AIMS) shows these fears have been realised. The percentage of living hard coral covering the Great Barrier Reef’s surface dropped in each region we surveyed.

The recent extreme highs and lows in coral cover are a troubling phenomenon. It raises the prospect that the Great Barrier Reef may reach a point from which it cannot recover.

Another global marine heatwave

In healthy corals, tiny algae produce both the coral’s main food source and its vibrant colours. When the water gets too warm, the algae are expelled and the coral’s tissue becomes transparent – revealing the white limestone skeleton beneath. This is called coral bleaching.

Coral can recover if temperatures are reduced and the relationship with the algae is restored, but it’s a stressful and difficult process. And if recovery takes too long, the coral will die.

In June 2023, a marine heatwave bleached coral reefs from the Caribbean to the Indian and Pacific Oceans.

It reached Australia’s east coast in February 2024, causing extensive coral bleaching. Aerial surveys showed three quarters of 1,080 reefs assessed had some bleaching. On 40% of these reefs, more than half the corals were white.

In the aftermath, in-water surveys measured how much coral died in the northern, central and southern Great Barrier Reef. The worst damage lined up with the highest levels of heat stress.

Sharp declines in coral cover

AIMS has surveyed reefs of the Great Barrier Reef each year since 1986, in a project known as the Long-Term Monitoring Program. It is the most extensive record of coral status on any reef ecosystem in the world.

One component of the surveys involves towing an expert observer behind a boat around the full perimeter of each reef. The observer records the amount of live, bleached and dead coral. These observations are then averaged for each location, and for each of the three regions of the Great Barrier Reef.

After each monitoring season we report on the percentage of living hard coral covering the Great Barrier Reef’s surface. It’s a coarse but robust, reliable indicator of the state of the Great Barrier Reef.

Coral losses this year were not uniform across the Great Barrier Reef. On the northern Great Barrier Reef, from Cape York to Cooktown, average coral cover dropped by about a quarter between 2024 and 2025 (from 39.8% to 30%). The largest declines on individual reefs (up to 70% loss) occurred near Lizard Island.

Reefs with stable or increasing coral cover were mostly found in the central region, from Cooktown to Proserpine. However, there was still a region-wide decline of 14% (from 33.2% to 28.6%), and reefs near Cairns lost between 17-60% of their 2024 coral cover.

In the southern reef (Proserpine to Gladstone) coral cover declined by almost a third. In the summer of 2024, southern reefs experienced the highest levels of heat stress ever recorded, resulting in substantial coral loss (from 38.9% to 26.9%).

The declines in the north and south were the largest in a single year since monitoring began 39 years ago.

Despite these losses, the Great Barrier Reef still has more coral than many other reefs worldwide, and remains a major tourist attraction. It’s possible to find areas that still look good in an ecosystem this huge, but that doesn’t mean the large-scale average hasn’t dropped.

More frequent bleaching events

Mass coral bleaching is becoming more frequent as the world warms.

Before the 1990s, mass bleaching was extremely rare. That changed in 1998 with the first major event, followed by another in 2002.

Back-to-back bleaching events occurred for the first time in 2016 and 2017. Since then, bleaching has struck the Great Barrier Reef in 2020, 2022, 2024, and again this year. The impacts of this year’s bleaching event will be revealed following the next round of surveys.

The time between these events is shrinking, giving corals less time to recover. Cyclones and crown-of-thorns starfish are also continuing to cause widespread coral loss.

You’ll see in the following charts how the percentage of coral cover has changed over time. The vertical yellow lines show the mass coral bleaching events increasing in frequency.

Confronting questions

The coral reefs of the future are unlikely to look like those of the past. The loss of biodiversity seems inevitable.

But will the reefs of the future still sustain the half a billion people that depend on them for food and income? Will they continue to protect coastlines from increasing storm activity and rising sea levels? These are confronting questions.

Effective management and research into reef adaptation and recovery interventions may bridge the gap until meaningful climate action is achieved. But above all, the key to securing a future for coral reefs is reducing greenhouse gas emissions.

Daniela Ceccarelli, Reef Fish Ecologist, Australian Institute of Marine Science; David Wachenfeld, Research Program Director – Reef Ecology and Monitoring, Australian Institute of Marine Science, and Mike Emslie, Senior Research Scientist in Reef Ecology, Australian Institute of Marine Science

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

The next UN Climate Change Conference - COP30 in Brazil

 
The 30th Conference of the Parties (COP) for the United Nations Framework Convention on Climate Change will be hosted by Brazil from 10th to 21st November 2025 in Belem, the capital of the state of Para. The city is located close to the Amazon, a crucial location given the climate change impacts on that crucial ecosystem and life resource.  There has been disquiet in the UN about the venue for COP30 as Belem is regarded as economically poor with limited capacity for dealing with an international conference of the size and scale of the COPs. For example, additional transport routes have had to be constructed for COP30 straining resources in Belem and including road construction in the Amazon itself.

Brazil holds the presidency for COP30 and has called for a course-correction as efforts to address climate change and meet agreed commitments are falling well behind stating: "the world must exponentially scale and speed up efforts to meet the commitments we have made".

The second global stocktake will take place  at COP30 measuring countries progress towards meeting the goals of the Paris Agreement. The first stocktake occured at COP28 and the results were far from reassuring. 

Brazil has proposed an action agenda for COP30 comprising six themes with a total of 30 objectives. The six themes are:

1. Transitioning Energy, Industry and Transport
2. Stewarding Forests, Oceans and Biodiversity
3. Transforming Agriculture and Food Systems
4. Building Resiliance for Cities, Infrastructure and Water
5. Fostering Human and Social Development
6. Cross-cutting issues - Unleashing Enablers and Accelerators, including on Finance, Technology and Capacity Building 

The sheer number of objectives and the wide scale of the themes appear far too ambitious and complex to achieve meaningful results and complete international agreement. Tangible results and concrete international cooperation are now essential given the increasingly dire situation.

The COP30 website can be accessed: COP30 Website 

Environmental contamination on the Earth - PFAS chemicals and a new acid rain

                                                          Nature (c) 

Science journal Nature has published further evidence of the pervasive impact of PFAS chemicals in the environment with the detection of trifluoroacetic acid (TFA) across the world in lakes, rivers, bottled water, beer, cereal crops, animal livers, human blood, urine and so on. It's been found in leaves and needles from trees in Germany, Canadian Arctic ice cores and ground water in Denmark. The concentration levels of TFA are rising with concerning increases being five to ten-fold in plants in some countries as one consequence. The graph above from Nature illustrates the increase. 

TFA is being distributed around the world through rain and snow. Wherever it rains, TFA comes with the water. 

TFA is a defined as a 'forever chemical'  as natural processes cannot break the strong carbon-fluorine bonds, a charcteristics of many of the PFAS substances. What is not clear is the health and environment impact on living things on the planet from the long term exposure to this chemical. Other PFAS chemicals have already been found to be carcinogenic. Continuing surveillence is warranted. 

Climate change - the Earth is continuing to heat and has passed the 1.5°C target

Only 3 years left – new study warns the world is running out of time to avoid the worst impacts of climate change

Piers Forster, University of Leeds and Debbie Rosen, University of Leeds

Bad climate news is everywhere. Africa is being hit particularly hard by climate change and extreme weather, impacting lives and livelihoods.

We are living in a world that is warming at the fastest rate since records began. Yet, governments have been slow to act.

The annual global climate change conference of the parties (COP30) is just months away. All of the 197 countries that belong to the United Nations were supposed to have submitted updated national climate plans to the UN by February this year. These plans outline how each country will cut its greenhouse gas emissions in line with the legally binding international Paris Agreement. This agreement commits all signatories to limiting human-caused global warming to no more than 1.5°C above pre-industrial levels.

Governments must also bring their newly updated national climate action plans to COP30 and show how they plan to adapt to the impacts that climate change will bring.

But so far, only 25 countries, covering around 20% of global emissions, have submitted their plans, known as Nationally Determined Contributions. In Africa, they are Somalia, Zambia and Zimbabwe. This leaves 172 still to come.

The nationally determined contributions are very important in setting out countries’ short- to medium-term commitments on climate change. They also provide a direction of travel that can inform broader policy decisions and investments. Aligning climate plans with development goals could lift 175 million people out of poverty.

But arguably only one of the submitted plans – the UK’s – is compatible with the Paris Agreement.

We are climate scientists, and one of us (Piers Forster) leads the global science team that publishes the annual Indicators of Global Climate Change report. This report gives an overview of the state of the climate system. It is based on calculations of the net emissions of greenhouse gases globally, how these are concentrating in the atmosphere, how temperatures are rising on the ground, and how much of this warming has been caused by humans.

The report also looks at how extreme temperatures and rainfall are intensifying, how much the sea levels are rising, and how much carbon dioxide can still be emitted before the planet’s temperature exceeds 1.5°C more than it was in pre-industrial times. This is important because staying within 1.5°C is needed to avoid the worst impacts of climate change.

Our report shows that human-caused global warming reached 1.36°C in 2024. This boosted average global temperatures (a combination of human-induced warming and natural variability in the climate system) to 1.52°C. In other words, the world has already reached the level where it has warmed so much that it cannot avoid significant impacts from climate change. There is no doubt we are in dangerous waters.

Our dangerously hot planet

Although last year’s global temperatures were very high, they were also alarmingly unexceptional. The data speaks for itself. Continued record high levels of greenhouse gas emissions have led to rising atmospheric concentrations of carbon dioxide, methane and nitrous oxide.

The result is rising temperatures that are rapidly eating into the remaining carbon budget (the amount of greenhouse gases that can be emitted within an agreed time). This will be exhausted in less than three years at current levels of emissions.

We need to face this head on: the window to stay within 1.5°C is essentially shut. Even if we can bring temperatures back down in future, it will be a long and difficult road.

At the same time, climate extremes are intensifying, bringing long-term risks and costs to the global economy but also, importantly, people. The African continent is now facing its deadliest climate crisis in over a decade.

It would be impossible to imagine economies operating without fast access to trusted data. When share prices plummet or growth stalls, politicians and business leaders act decisively. None would tolerate outdated intelligence on sales or the stock market.

But when it comes to climate, the speed of climate change often outpaces the data available. This means fast decisions can’t be made. If we treated climate data as we do financial reports, panic would ensue after each dire update. But while governments routinely pivot when faced with an economic downturn, they have been far slower to respond to what key climate indicators – the Earth’s vital signs – are telling us.

What needs to happen next

As more countries develop their climate plans, it’s time for leaders across the globe to face the hard truths of climate science.

Governments need to have fast access to trusted climate data so that they can develop up-to-date national climate plans. The national climate plans need to take a global perspective too. This is really important for fairness and equity. For example, developed countries must acknowledge that they’ve emitted more greenhouse gases and take the lead in presenting ambitious mitigation efforts and in providing finance for other countries to decarbonise and adapt.

In Africa, the UN is hosting UNFCCC Climate Week in Addis Ababa in September. As well as making plans for COP30, there will be sessions on accessing climate finance and ensuring that the transition to zero human-caused carbon emissions by 2050 (net zero) is just and equitable. The summit also aims to support countries that are still working on their national climate plans.

If nationally determined contributions are implemented, the pace of climate change will slow down. This is vital not just for the countries – and economies – currently on the frontline against climate change, but for a functioning global society.

Just five of the G20 countries have submitted their 2035 plans: Canada, Brazil, Japan, the United States and the United Kingdom. But the G20 is responsible for around 80% of global emissions. This means that South Africa’s current G20 presidency can help to ensure that the world prioritises efforts to help developing countries finance their transition to a low-carbon economy.

Another worrying factor is that just 10 of the updated nationally determined contributions have reaffirmed or strengthened commitments to move away from fossil fuels. This means that national climate plans from the European Union, China and India will be key in testing their climate leadership and keeping the Paris Agreement’s 1.5°C temperature goals alive. Many other countries will be scrutinising what these countries commit to before they submit their own national climate plans.

The data in our report helps the world to understand not just what’s happened in recent years, but also what to expect further down the track.

Our hope is that these and other countries submit ambitious and credible plans well before COP30. If they do, this will finally close the gap between acknowledging the climate crisis and making decisive efforts to address it. Every tonne of greenhouse gas emissions matters.

Piers Forster, Professor of Physical Climate Change; Director of the Priestley International Centre for Climate, University of Leeds and Debbie Rosen, Research and Innovation Development Manager for the Priestley Centre for Climate Futures, University of Leeds

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

Sunscreens - Therapeutic Goods Administration Review of chemicals

How safe are the chemicals in sunscreen? A pharmacology expert explains

aquaArts studio/Getty

Ian Musgrave, University of Adelaide

Last week, the Therapeutic Goods Administration (TGA) released its safety review of seven active ingredients commonly used in sunscreens.

It found five were low-risk and appropriate for use in sunscreens at their current concentrations.

However, the TGA recommended tighter restrictions on two ingredients – homosalate and oxybenzone – to reduce how much can be used in a product. This is based on uncertainty about their potential effects on the endocrine system, which creates and releases hormones.

This news, together with recent reports some products may have inflated their claims of SPF coverage, might make Australians worried about whether their sunscreen products are working – and safe.

But it’s not time to abandon sunscreens. In Australia, all sunscreens must pass a strict approval process before going on the market. The TGA tests the safety and efficacy of all ingredients, and this recent review is part of the TGA’s continuing commitment to safety.

The greatest threat sunscreen poses to Australians’ health is not using it.

Australia has the highest incidence of melanoma and non-melanoma skin cancer worldwide, and approximately 95% of melanoma cases in Australia are linked to ultraviolet (UV) exposure.

Still, it’s understandable people want to know what’s in their products, and any changes that might affect them. So let’s take a closer look at the safety review and what it found.

What are the active ingredients in sunscreen?

There are two main types of sunscreen: physical and chemical. This is based on the different active ingredients they use.

An active ingredient is a chemical component in a product that has an effect on the body – basically, what makes the product “work”.

In sunscreens, this is the compound that absorbs UV rays from the Sun. The other ingredients – for example, those that give the sunscreen its smell or help the skin absorb it – are “inactive”.

Physical sunscreens typically use minerals, such as titanium dioxide and zinc oxide, that can absorb the Sun’s rays but also reflect some of them.

Chemical sunscreens use a variety of chemical ingredients to absorb or scatter UV light, both long wave (UVA) or short wave (UVB).

The seven active ingredients in this review are in chemical sunscreens.

Why did the TGA do the review?

Our current limits for the concentrations of these chemicals in sunscreen are generally consistent with other regulatory agencies, such as the European Union and the US Food and Drug Administration.

However, safety is an evolving subject. The TGA periodically reexamines the safety of all therapeutic goods.

Last year, the TGA revised its method of estimating sunscreen exposure to more closely model how skin is exposed to sunscreens over time.

This model considers how much sunscreen someone typically applies, how much skin they cover (whole body versus face and hands, or just face) and how it’s absorbed through the skin.

Given this new model – along with changes in the EU and US approaches to sunscreen regulation – the TGA selected seven common sunscreen ingredients to investigate in depth.

Determining what’s safe

When evaluating whether chemicals are safe for human use, testing will often consider studies in animals – especially when there is no or limited data on humans. These animal tests are done by the manufacturers, not the TGA.

To take into account any unforeseen sensitivity humans may have to these chemicals, a “margin of safety” is built in. This is typically a concentration 50–100 times lower than the dose at which no negative effect was seen in animals.

The sunscreen review used a margin of safety 100 times lower than this dose as the safety threshold.

For most of the seven investigated sunscreen chemicals, the TGA found the margin of safety was above 100.

This means they’re considered safe and low-risk for long-term use.

However, two ingredients, homosalate and oxybenzone, were found to be below 100. This was based on the highest estimated sunscreen exposure, applied to the body at the maximum permitted concentration: 15% for homosalate, 10% for oxybenzone.

At lower concentrations, other uses – such as just the hands and face – could be considered low-risk for both ingredients.

What are the health concerns?

Homosalate and oxybenzone have low acute oral toxicity – meaning you would need to swallow a lot of it to experience toxic effects, nearly half a kilogram of these chemicals – and don’t cause irritation to eyes or skin.

There is inconclusive evidence about oxybenzone potentially causing cancer in rats and mice – but only at concentrations to which humans will never be exposed via sunscreens.

The key issue is whether the two ingredients affect the endocrine system.

While effects have been seen at high concentrations in animal studies, it is not clear whether these translate to humans exposed to sunscreen levels.

No effect has been seen in clinical studies on fertility, hormones, weight gain and, in pregnant women, fetal development.

The TGA is being very cautious here, using a very wide margin of safety under worst-case scenarios.

What are the recommendations?

The TGA recommends the allowed concentration of homosalate and oxybenzone be reduced.

But exactly how much it will be lowered is complicated, depending on whether the product is intended for adults or children, specifically for face, or the whole body, and so on.

However, some sunscreens would need to be reformulated or warning labels placed on particular formulations. The exact changes will be decided after public consultation. Submissions close on August 12.

What about benzophenone?

There is also some evidence benzophenone – a chemical produced when sunscreen that contains octocrylene degrades – may cause cancer at high concentrations.

This is based on studies in which mice and rats were fed benzophenone well above the concentration in sunscreens.

Octocrylene degrades slowly over time to benzophenone. Heat makes it degrade faster, especially at temperatures above 40°C.

The TGA has recommended restricting benzophenone to 0.0383% in sunscreens to ensure it remains safe during the product’s shelf life.

The Cancer Council advises storing sunscreens below 30°C.

The bottom line

The proposed restrictions are very conservative, based on worst-case scenarios.

But even in worst-case scenarios, the margin of safety for these ingredients is still below the level at which any negative effect was seen in animals.

The threat of cancer from sun exposure is far more serious than any potential negative effect from sunscreens.

If you do wish to avoid these chemicals before new limits are imposed, several sunscreens are available that provide high levels of protection with little or no homosalate and oxybenzone. For more information, consult product labels.

Ian Musgrave, Senior Lecturer in Pharmacology, University of Adelaide

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