How rising sea levels will affect our coastal cities and towns

The Conversation - Thomas Mortlock

Darren Pateman/AAP

AUTHOR Thomas Mortlock Adjunct Fellow Climate Change Research Centre UNSW

Sea-level rise – along with increasing temperatures – is one of the clearest signals of man-made global warming. 

Yet exactly how rising water levels affect the coast is often misunderstood.

A new coastal hazard assessment for Victoria’s Port Phillip Bay has again thrown the spotlight on the impact of sea-level rise on coastal communities in Australia. Should we be worried? Or is the reality more nuanced?

While there are still many uncertainties, even a small change in sea level can have big impacts. We should be doing all we can to limit sea-level rise to protect our coastal cities and towns. And because sea levels will continue to rise for centuries after we cut emissions to net zero, planning decisions for coastal areas must factor this in.

Why are sea levels rising?

Global sea levels are rising for two main reasons: the oceans are getting warmer, and land-based ice sheets and glaciers are melting.

As ocean water warms, it expands. Because the ocean basins are finite (like a bathtub), this results in a rise in water levels.

Since the 1970s, thermal expansion of the oceans has accounted for roughly half of measured global sea-level rise. The other half is due to land-based ice melt from ice sheets and glaciers. Together, these make up what is known as “eustatic” sea level.

The rate of sea-level rise experienced at the coast also depends on whether the land is moving up or down. “Relative” or “isostatic” sea level is the sum of “eustatic” sea level plus local vertical land movement.

Australia is rising by about 0.3-0.4 millimetres a year due to glacial isostatic adjustment. This is the result of the land continuing to move upward following the loss of ice on land during previous glaciations. The land subsided under the weight of this ice and is now rebounding as the ice is gone. This slow rebound of the land provides a small offset to eustatic sea levels around Australia.

Sea-level rise is accelerating

From 1900 to 2018, global sea levels rose by about 20cm (a long-term average of 1.7mm/yr), but almost everywhere the rate of rise is increasing. Measurements since 1993, when global satellite data became available, show the rate of global mean sea-level rise over the past decade has more than doubled to more than 4mm/yr.

Around Australia, sea levels are rising at or above this global average. Tide gauges indicate the rate of rise in northern Australia since the early 1990s is around 4–6mm/yr. Along the south-east coast of Australia, it’s about 2–4mm/yr. Rates of sea-level rise are not uniform around Australia because of local effects like ocean circulation and tidal processes.

Even if greenhouse gas emissions reached zero tomorrow, sea levels will continue to rise for several centuries because of the slow response of the ocean to warming. It’s a long-term trend that we must live with.

This is why is it important to factor in sea-level rise when we make planning decisions along the coast. Unfortunately, the rate of sea-level rise over the coming century remains highly uncertain, making it difficult to include in coastal planning.

The “likely” range of the most recent projections by the Intergovernmental Panel on Climate Change (IPCC) is a rise of between 0.4 metres and 0.8m by 2100. However, a rise of nearly 2m by 2100 and 5m by 2150 cannot be ruled out. This is due to deep uncertainty about ice-sheet processes – so much so, that in 2021 the IPCC introduced a new high- end risk scenario to describe this.

Small rises have big impacts

The impact of sea-level rise at the coast is not just a gradual increase in water lapping at the shore. An increase in tide heights (both higher high tides and higher low tides) increases the probability of coastal flooding and erosion when storms come along.

As a rule of thumb, every 10cm of sea-level rise triples the frequency of a given coastal flood. Another rule of thumb, known as the Bruun Rule, suggests a 1cm rise in sea level leads to a 1m retreat of the coastline.

While these back-of-the-envelope estimates are often significantly reduced when local conditions are accounted for, it explains why a small shift in the mean sea level can have big impacts at the coast.

Storms aren’t always bad for the beach

Most of the impacts of sea-level rise around Australia’s coast will be felt in combination with storm events, such as east coast lows or tropical cyclones. A high water level plus a storm surge on top leads to a storm or “king” tide. In combination with storm waves, it can cause significant coastal erosion and flooding.

However, storms also bring sand from deeper water towards the beach. Over the long term, this process can help beaches keep pace with sea-level rise. Fortunately for eastern Australia, we have a lot of sand sitting offshore which is slowly making its way back to our beaches. Other naturally regressive coastlines, such as many in Northern Europe, are not so lucky.

All eyes on Antarctica

Sea-level rise is here to stay and gathering pace, but the rate of future increase remains uncertain. It largely depends on what happens in Antarctica over the coming decades.

This in turn depends on land and sea temperatures around the southern continent, which are directly linked to our efforts to limiting global warming to 1.5°C in line with the Paris Agreement.

With over 250 million people now living on land less than 2m above sea level, most in Asia, it is imperative we do everything we can to limit future sea-level rise.

Links

• Ocean heat is off the charts – here's what that means for humans and ecosystems around the world
• Rising seas and melting glaciers: these changes are now irreversible, but we have to act to slow them down
• Coastal property prices and climate risks are both soaring. We must pull our heads out of the sand
• Climate explained: why coastal floods are becoming more frequent as seas rise
• Become a beach scientist this summer and help monitor changing coastlines
• The heat is on: what we know about why ocean temperatures keep smashing records
• An economist explains: Textbook economics is badly flawed when it comes to climate change 

Sea-level rise: a new method to estimate the probability of different outcomes – including a worst case

The Conversation - Benjamin P. Horton   Benjamin S. Grandey

An aerial view of the Greenland ice cap near the island’s capital, Nuuk. Vadim_N/Shutterstock

AUTHORS Benjamin P. Horton Director of the Earth Observatory of Singapore, Nanyang Technological University Benjamin S. Grandey Senior Research Fellow, School of Physical & Mathematical Sciences, Nanyang Technological University

Here is a depressing fact: over the coming decades, sea-level rise will continue to threaten ecosystems, communities and cities. 

No matter how quickly we reduce our carbon emissions, our past emissions commit us to ongoing sea-level rise, given the long-drawn-out impact of climate warming on the oceans and ice sheets. 

Just how bad it gets, however, will depend on our current and future emissions.

Even as we strive for net-zero emissions, we must prepare for devastating possibilities. But decision-makers face a major obstacle: the specific rate and magnitude of future sea-level rise is deeply uncertain. 

Different methods produce different projections of long-term sea-level rise. The problem of reconciling these different methods and projections has undermined planning to protect people from future sea-level rise.

In a recent paper published in Earth’s Future, we and our colleagues tackle this problem. We propose a new method that combines the complementary strengths of different sea-level projections. 

We use our method to quantify the uncertainty of future sea-level rise. It allows us to estimate a “very likely” range. “Very likely” means that there is a 9-in-10 chance (90% probability) that future sea-level rise will lie within this range, if our future emissions follow an assumed emissions scenario.

Under a low-emissions scenario that corresponds to approximately 2°C warming above pre-industrial levels, global sea level will “very likely” rise between 0.3 and 1.0 metres by the end of this century. 

Under a high-emissions scenario that corresponds to approximately 5°C warming, global sea level will “very likely” rise between 0.5 and 1.9 metres. Given that we will likely exceed 2°C warming, preparing for more than a metre of sea-level rise by 2100 is, therefore, necessary.

Adapted from Grandey et al. (2024). Benjamin P. Horton and Benjamin S. Grandey, CC BY-ND

The challenge of poorly understood processes

Our method builds on and complements the current reference document for many decision-makers: the Intergovernmental Panel on Climate Change’s Sixth Assessment Report IPCC 6AR. For five emissions scenarios, the IPCC published a most-likely “median” projection and a “likely” range. 

“Likely” means that there is at least a 2-in-3 chance (66% probability) of sea-level rise within this range. The “likely” range may understate the risk of more extreme possibilities, a weakness that can be addressed by a complementary “very likely” range. 

However, the IPCC did not estimate a “very likely” range because poorly understood ice sheet processes posed a challenge. We address this challenge, to provide decision-makers with more reliable estimates of future possibilities.

Many processes contribute to sea-level rise. Of particular importance are ice sheet processes in Greenland and Antarctica. Some of these ice sheet processes are well understood, but others less so. We have only a poor understanding of processes that could drive abrupt melting of ice, producing rapid sea-level rise.

Climate models and ice sheet models, such as those used in the IPCC 6AR, are very good at simulating well-understood processes, such as thermal expansion of the ocean. The IPCC used model-based projections to derive a reliable median projection and “likely” range. 

However, these models often neglect poorly understood processes that could cause the ice sheets to melt much faster than we expect. To complement the models, experts can provide alternative projections based on their understanding of these processes. 

This is known as expert elicitation. Therefore, the use of models and expert elicitation can provide complementary sea-level projections, but planners have great difficulty deciding when and where to apply the two different approaches.

In our paper, we have developed a novel method to combine the complementary sea-level projections from models and experts. We use our method to quantify the full uncertainty range of future sea-level rise using a probability distribution. 

This is how we can estimate a “very likely” range and explore the question, “What high-end sea-level rise should we plan for?”

A high-end projection

To make informed judgements, decision-makers often need information about low-likelihood, high-cost possibilities. 

A high-end projection of sea-level rise is especially useful when planning long-lasting critical infrastructure that is vital for the functioning of society and the economy. 

A high-end projection can also highlight a catastrophic risk associated with unrestrained carbon dioxide emissions.

We define our high-end projection as the 95th percentile of the probability distribution under the high-emissions scenario. Our high-end projection of global sea-level rise is 1.9 metres by the end of this century.

Our high-end projection complements existing high-end projections of 21st century sea-level rise. The IPCC 6AR included two: 1.6 metres and 2.3 metres. Our projection of 1.9 metres falls between these two values.

In contrast to the IPCC 6AR, we estimate the probability of reaching the high-end projection. If our future emissions follow the high-emissions scenario, we estimate that the probability of reaching 1.9 metres by the end of this century is 5% (1 in 20). 

Considering that the high-emissions scenario is unlikely, our high-end projection can be interpreted as a worst-case outcome. 

We also estimate the probability of exceeding 1.0 metres by the end of this century: 16% (about 1 in 6) under the high-emissions scenario, and 4% (1 in 25) under the low-emissions scenario.

Reducing the uncertainty

Through climate science, we have learned much about the Earth’s climate system. However, we still have much more to discover. As our understanding improves, the uncertainty in sea-level rise should reduce. 

Therefore, the “very likely” range of future sea-level rise should narrow, due to the ongoing research efforts of the climate science community.

Co-author Benjamin P. Horton in Antarctica. Benjamin P. Horton, Author provided (no reuse)

In the meantime, we need to identify potential solutions that can reduce coastal flood risk in ways that support the long-term resilience and sustainability of communities and the environment, and reduce the economic costs associated with flood damage. 

Alongside local adaptation, the best way to mitigate sea-level rise is to slow down climate change by implementing the commitments laid out in the Paris Agreement in 2015.

If we can limit warming to well below 2°C, consistent with the agreement, we estimate that the probability of reaching 1.9 metres by the end of the century shrinks to less than 0.2% (1 in 500). 

The more the world limits its greenhouse gas emissions, the lower the chance of triggering rapid ice loss from Greenland and Antarctica, and the safer we will be.

Links

• Newly discovered Australian frogs highlight dire limits of climate change adaptation
• World urged to stay the course on climate action as Trump turns away
• The climate crisis is a cost of living issue for Australia. My generation will be the first to pay for it | Anjali Sharma
• Net-zero homes are touted as a solution for climate change, but they remain out of reach for most
• 2024 Corruption Perceptions Index: Corruption is playing a devastating role in the climate crisis
• Outcry as Trump withdraws support for research that mentions ‘climate’
• How Trump could be derailing a major global climate report

Climate misinformation and disinformation is rife. Could you spot fake content online?

Jennifer Scherer - SBS News

The spread of mis and disinformation online is putting the planet at risk.

The spread of false information is one the biggest global risks, according to the World Economic Forum, and experts warn the proliferation of climate denialism could stall urgent action.

The flood that swept through western Germany and eastern Belgium in 2021 claimed the lives of more than 200 people.

Gerd Schiffer is leading the reconstruction of the German town of Erftstadt, which was badly damaged by the flooding, and feels the spread of climate denial delays disaster preparedness.

"There are still many climate change deniers but if they themselves would be affected, they would certainly have a different perspective," Schiffer told SBS News.

"It is a real risk that the population is not taking it seriously, with the attitude that 'it won't happen here or it won't happen to me'."

The sinkhole in the Blessem district of Erftstadt, Western Germany in July 2021. Source: AFP

The proliferation of misinformation, spread due to error or mistake, and disinformation, which is designed to deliberately mislead or influence, is on the rise globally.

Unchecked information can be disseminated through social media platforms, algorithmic recommendations and the growing influence of generative artificial intelligence, which can be used to create fake content.

Alexander Sängerlaub is the founder of Futur Eins, a think-and-do tank which looks at the future and resilience of digital spheres.

"We live in the age of information floods," he told SBS News.

"Imagine you are on Instagram or Twitter, there's a lot of information, information snippets … opinion-based things, fact-check based.

"We are basically overwhelmed to sort things in the right direction, to understand 'is this good information, is this a lie?'"

Alexander Sängerlaub is the founder of Futur Eins. Credit: SBS News, Jennifer Scherer.

What’s being done to curb the problem?

Controlling the spread of misinformation and disinformation has been labelled by the United Nations as one of the most urgent tasks of our time.

Last year, UN Secretary-General António Guterres put forward a framework to promote a coordinated global response to safeguarding information spaces.

It encouraged the implementation of state-led regulatory frameworks to promote transparency while cautioning against infringing on rights including freedom of opinion and expression. It promoted the protection of free and independent media, urging stakeholders such as government, tech companies, advertisers and media to stop using or amplifying disinformation and hate speech.

Countries such as Germany have adopted legal frameworks to make big tech responsible for the spread of disinformation. The European Union's Digital Services Act (2022) aims to address illegal and harmful content and the spread of disinformation by enforcing rules on online intermediaries such as search engines, social media platforms or online marketplaces.

In Australia, a bill to further crack down on misinformation and disinformation was quashed in November 2024, due to concerns around safeguarding freedom of expression.

Sängerlaub says there's too much responsibility on consumers and too little on platforms to educate the public on what disinformation is.

"Social media should do the work for us [and be] much more responsible in working together with fact-checking organisations or with systems that are helping people to understand how these platforms are working."

On a global scale, Henning Wuester, the director of the Initiative for Climate Action Transparency, suggests data could be a useful antidote to misinformation, especially when driving collective action through mechanisms such as the Paris Agreement.

"Transparency is really the glue that holds everything together, it ensures that the decentralised action in countries comes together," Wuester told SBS News.

"The biggest challenge is that many countries do not have data and do not have a framework to collect regularly the data that is required in order to plan their climate action in a meaningful way.

"As soon as you have the necessary and good quality data, that provides a basis for planning, you can deal with the misinformation."

Spotting fake or false information

According to the Climate Social Science Network, there are extensive networks across Europe trying to obstruct climate action. In Germany, an increase in climate denial has been linked to the rise of far-right ideology.

Ahead of Germany’s federal election, far-right party Alternative für Deutschland (AfD) appears to be gaining traction, some opinion polls placing it in second place behind the Christian Democratic Union (CDU) and its Bavarian CSU sister party coalition.

The AfD is the only large party to reject climate action.

A YouGov Deutschland poll placed the AfD in second place ahead of the German election.

"Climate denial will not stop the climate crisis," Laura Schäfer from German Watch, an independent development, environmental, and human rights organisation, told SBS News.

"The physics are clear and also the impacts are clear.

"It is of course the Pacific, and other people and countries most vulnerable who are then feeling the impact of that."

Debunking misinformation and disinformation online often relies on digital consumers to check the source and publisher of information.

According to Katharina Wecker from the Climate Journalism Network Germany, subtle disinformation which is aimed at delaying climate action is a "massive threat".

"I think it's part of media literacy that people need to learn, or even students and people at school should learn to fact check sources, to learn which sources to trust," Wecker said.

When it comes to verifying images, footage or deep fakes, tips can include searching for media reports to support claims, paying attention to inconsistencies in the appearance of images or footage as well as conducting a reverse-image search to try to find the original source.

Laura Schäfer from Germanwatch, an independent development, environmental, and human rights organisation. Credit: SBS News, Jennifer Scherer.

Urgent action needed

The spread of climate denial content has also concerned experts who warn a weakening in public support for green initiatives could escalate the impacts of a changing climate.

"It is very unjust that those who have emitted greenhouse gas emissions like Germany and other industrialised countries, they are not the ones at the front[line] of consequences," Mechthild Becker from the German Council on Foreign Relations told SBS News.

"Those in the Pacific, especially on small island and development states … some already have had to leave their homes, already planned relocations have taken place."

Germany has committed to climate-related assistance abroad, including pledging aid to the Pacific. Both Germany and Australia have committed through the Pacific Islands Forum to support regional priorities, including pooling resources and helping with disaster preparedness and response.

Mechthild Becker is a climate and foreign policy research fellow at the German Council on Foreign Relations. Credit: SBS News, Jennifer Scherer

.

Tuvalu Prime Minister Feleti Penitala Teo worries about the future.

"The current situation on the ground is quite desperate. We are witnessing day in, day out, the impact of sea level rise," he told SBS News.

"The current predictions by scientists … are quite daunting and frightening. They are predicting that in 25 years, in 2050, more than 50 per cent of the land territory of Tuvalu will be regularly flooded by regular tidal surges.

"In another 50 years … more than 90 per cent of the land territory of Tuvalu will be suffering the same fate."

In 2023, Tuvalu and Australia signed a treaty providing a migration pathway due to the impacts of climate change on the island nation.

Despite witnessing the impacts of climate change first hand, Teo says the Pacific is not immune to mis and disinformation.

"I think it's incumbent on those developed countries, especially those that are responsible for this phenomenon, to ensure that misinformation and disinformation are addressed quickly," he said.

"It's a constant challenge for countries like Tuvalu where we don't have robust cybersecurity infrastructure."

 

In countries such as Tuvalu, Fiji and Samoa, 80 per cent of the population is online, with many turning to social media for news consumption.

"With the rise of access to things like social media, a lot of the narratives that rise within the diasporic communities, whether it's in Australia or Aotearoa or the US, they also seem to find their way to filter into our islands," Joseph Sikulu the pacific director for 350.org, an organisation promoting renewable energy, told SBS News.

"You hear some really conservative narratives now flourishing up within our island communities.

"Whether it's social media, whether it's within this coconut wireless of people talking to each other or whether it's within our church, there is a lot of disinformation, misinformation that spreads amongst our people."

 

Links

• What are climate misinformation and disinformation and what is their impact?
• Climate Misinformation on Social Media Is Undermining Climate Action  
• Here are 10 myths about climate change - WWF
• Activists or extremists? The protesters willing to go to jail to defend their cause 
• Australia to offer residency to hundreds from Tuvalu, nation at high risk from climate change
• 'No pathway': Government drops controversial misinformation bill amid Senate opposition

Newspaper and Book News and Reviews - Lethal Heating Editor BDA

Recent developments in climate change and global warming highlight the escalating challenges and the urgent need for action:

Record-Breaking Global Temperatures in 2024 - The Times UK

In 2024, Earth experienced its hottest year on record, with global temperatures surpassing pre-industrial levels by 1.5°C—a critical threshold outlined in the Paris Agreement. This unprecedented warming has intensified extreme weather events, including heatwaves, floods, and droughts, posing severe threats to ecosystems and human populations. 

All major temperature datasets, such as those from NASA and the UK's Met Office, confirm this alarming trend. While greenhouse gas emissions remain the primary driver, natural phenomena like El Niño have also contributed to the temperature surge.

Antarctic Heat Wave - Wikipedia

In July 2024, Antarctica experienced a significant mid-winter heat wave, with temperatures soaring up to 28°C above average. This event, occurring during a period typically marked by the continent's coldest temperatures, led to a substantial reduction in sea ice levels. 

Researchers attribute this anomaly to a weakened polar vortex, influenced by atmospheric disturbances and exacerbated by climate change. The resulting loss of sea ice contributes to a feedback loop, further accelerating global warming.

Water Crisis in Kashmir - AP News

Kashmir, renowned for its Himalayan peaks and pristine lakes, is confronting a severe water crisis. Prolonged dry spells and rising temperatures have led to the drying up of multiple springs and streams, including vital tributaries of the Jhelum River. 

This situation has disrupted local communities and ecosystems, underscoring the tangible impacts of climate change on water resources. Experts point to significant deficits in rainfall and snowfall, coupled with unusually high temperatures, as key factors driving this crisis.

Global Climate Assessment Concerns - Reuters

The European Union, the United Kingdom, and several climate-vulnerable developing nations have expressed apprehension over potential delays in the upcoming global climate assessment by the U.N.'s Intergovernmental Panel on Climate Change (IPCC). 

These concerns arise following the U.S. administration's withdrawal from the process, which could impede the timely completion of the assessment crucial for informing the 2028 Paris Agreement "stocktake." The absence of U.S. involvement, including the participation of its scientists, poses challenges to the collaborative efforts essential for comprehensive climate evaluations. 

Literature on Climate Solutions

Recent publications offer diverse perspectives on addressing climate change:

Marco Visscher's "The Power of Nuclear" reevaluates nuclear energy as a viable low-carbon power source. 

Ma Tianjie's "In Search of Green China" delves into China's complex journey toward emission reduction amid economic growth. 

Mike Berners-Lee's "A Climate of Truth" advocates for heightened honesty in confronting interconnected global challenges.

Jens Beckert's "How We Sold Our Future" emphasizes the necessity for systemic changes in corporate and consumer behaviors to achieve meaningful climate action.

These developments underscore the escalating impacts of climate change and the critical need for immediate, coordinated global efforts to mitigate its effects.

Links

• If not now, when? Australia must urgently ramp up climate action following record-breaking year
• Australia: Climate change and extreme events
• Australia’s climate change strategies
• Countries warn against delaying global climate assessment after US exit
• Famed for Himalayan peaks and pristine lakes, Kashmir faces a water crisis amid dry weather
• Two-thirds of the Earth's surface experienced record heat in 2024. See where and by how much - visualised

Extreme Weather is Australia's New Normal

Professor Todd Lane - PURSUIT University of Melbourne

Banner: Getty Images

Over the last few weeks, parts of Australia have been inundated by rain, scorched by heatwaves and slammed by storms. 

Is this our country's new normal? how hot was it yesterday? Did those storms keep you awake? What’s happening with the fires? Have you seen how much rain is falling up North?

We all love to talk about the weather, and right now it is the hot topic (excuse the pun) of conversation across much of Australia. 

A sweltering heatwave has breathed new life into existing bushfires in Victoria's west. Picture: AAP

Many parts of Australia are in the middle of a heatwave, Far North Queensland is suffering from extreme flooding, there’s a tropical cyclone off the coast of Western Australia, we have out-of-control bushfires fuelled by the hot and windy conditions and severe storms are popping up in many places across the country.

Is this the new normal?

We have always had extreme weather in Australia. But human-caused climate change is warming Australia and surrounding oceans at an unnatural pace, changing our weather patterns and modifying the structure and moisture content of the atmosphere. 

These all ultimately lead to changes in the occurrence and intensity of many extreme weather events.

We can expect heatwaves to get hotter and longer, extreme rainfall from thunderstorms should get heavier and fire weather days are likely to increase in number.

These changes depend on location and scientists have more confidence in trends for some extremes compared to others. Nonetheless, there is high confidence that the ‘new normal’ is more extreme than the old one.

It is possible to determine whether a specific extreme event or group of events, like those many of us are experiencing now, are made more likely or more intense by climate change.

The process is called ‘event attribution’ and it typically requires detailed data analysis after the fact, a well-developed scientific understanding of the impact of climate change on extreme weather events and realistic simulation capability.

Large parts of the nation's north faced severe flooding, with some areas recording more than a metre of rain. Picture: AAP Image

In 2023, a group of a group of Australia’s climate science experts (including myself) published a report on which extreme events could be robustly linked to climate change. We found that we can be most confident in statements connecting individual heatwaves and climate change.

Some of the more complicated or difficult-to-measure extreme events, like heavy rain and bushfires, can only be directly linked to global warming with low to medium confidence.

This means there’s still more research to be done to work out what the ‘new normal’ looks like, including how this might be different in a net zero world compared to one where net greenhouse gas emissions continue to increase.

The way most of the world will experience climate change is through changes in our weather. What we can say with confidence is that the new normal will feature high-impact weather events that test our resilience to climate change.

As these extremes play out, they highlight some of our future societal challenges.

In the coming years, we will break more heatwave records, especially in cities. Heatwaves kill more people in Australia than any other environmental hazard, and it’s our most vulnerable – the elderly and lower socioeconomic groups – that are most at risk.

Flash floods as a result of rainbursts will be more intense because the warmer atmosphere can hold more water. This damages our property and infrastructure, impacts agriculture and poses a risk to life.

Parts of Australia continue to experience heatwave conditions. Picture: Getty Images

It is no accident that all these extremes are happening at once.

One of the wonders of the atmosphere is how simultaneous extreme events are connected by larger-scale weather systems.

The current high-pressure system in the Tasman Sea sets up the conditions that cause both the wet extremes in the north and the heat extremes in the south.

Fires and heatwaves also go hand-in-hand.

This tendency for extremes in Australia to occur at the same time – known as compound events – poses obvious additional challenges for emergency services and response networks who might already be stretched to their limits.

Unfortunately, our world continues to warm and extreme weather events will keep changing. This makes the concept of the ‘new normal’ poorly defined.

What is clear, however, is that society needs ongoing efforts to adapt to and mitigate the impacts of extremes like those we are now experiencing across the country.

These adaptations can range from policy changes, investments in more climate-resilient infrastructure, local community-based support and more. For example, the City of Melbourne supports community organisations to provide ‘Cool Places’ during extreme heat events to those most vulnerable.

At the same time, our ability to predict dangerous weather events is improving. Weather agencies use the latest supercomputing technology to forecast extremes more accurately and with more lead time than ever before.

This summer has seen Australia's Bureau of Meteorology issue several severe heatwave warnings. Picture: Getty Images

This capability, which should continue to improve with ongoing investment in research and development, adds to our ability to prepare for extremes.

What is clear is that extremes will be part of our ‘new normal’, but that doesn’t mean we should feel resigned to this future.

As a planet, we still have the power to limit the occurrence and impact of future extremes through reductions in emissions and achieving net zero as quickly as possible.

Links

• Understanding climate change
•  Attribution of extreme events to climate change in the Australian region – A review
• What does net zero emissions mean?
• do nothing’ approach won’t help Australia deal with bushfires as the climate gets hotter
• What will the America First Directive mean for international climate policy?
• Heatwaves and climate change are Australia’s deadliest ‘unnatural’ disaster

Developing world urges rich nations to defy Trump’s ‘climate nihilism’

Fiona Harvey Environment editor The Guardian

Poorer countries want rapid emission cuts and more financial help in face of US leader’s stance on global heating

All countries are supposed to come up with stringent national plans on cutting emissions at Cop30 in Brazil this year. Photograph: Michel Euler/AP

Developing countries are calling on the rich world to defy the US president, Donald Trump, and bridge the global chasm over climate action, before the goal of limiting global temperatures to safe levels is irretrievably lost.

Diplomats from the developing world are rallying to support Brazil, which will host a crucial climate summit in November, after last year’s talks in Azerbaijan ended in disappointment and acrimony.

Ali Mohamed, the chair of the African group of negotiators and Kenya’s special envoy for climate change, pointed to record temperatures last year and continuing extreme weather. “Africa, responsible for less than 4% of global greenhouse gas emissions, remains disproportionately affected by the intensifying impacts of climate change,” he said. “It is unacceptable that this devastation is caused by the pollution of just a few countries in the world, specifically the G20, and they must take responsibility for their actions.”

As well as needing rich countries to cut their emissions, vulnerable nations need financial help, as they struggle to cope with the devastation they are already seeing. “Adaptation is the priority for us, not a priority,” said Evans Njewa, chair of the least developed countries group. “We are prioritising adaptation, for our key sources of livelihood, and our economies. [Adaptation is essential to our] agriculture, water, the management of natural resources, food security and nutrition.”

On his first day in his second term as president, Donald Trump signed a letter giving notice to UN that the US was withdrawing from the Paris agreement. Photograph: Andrew Caballero-Reynolds/AFP/Getty Images

Trump’s withdrawal from the Paris agreement came after a fraught and unsatisfactory ending to the Cop29 summit in Baku in November, at which poor countries were promised $1.3tn a year in climate finance by 2035, but of that sum only $300bn is to come chiefly from developed countries. The rest would be made up in hoped-for private sector finance and from potential levies, such as taxes on shipping and frequent flyers, which have yet to be agreed.

For many in the developing world, this is not good enough. If they are to play a role in curbing carbon – and most of the future growth in emissions is projected to come from the developing world – they are demanding a better financial settlement.

“The failure of Cop29 to secure sufficient financing for developing countries – those most affected by climate impacts – represents a grave setback,” said Harjeet Singh, a climate activist and the founding director of the Satat Sampada Climate Foundation. “Without this support, their recovery efforts and transitions to renewable energy are severely hindered, jeopardising global emission reduction goals and exacerbating the climate crisis.

Activists attend a protest at Cop29 in Baku, Azerbaijan. Photograph: COP29 Azerbaijan/EPA

At Cop30 in Belém, Brazil, all countries are supposed to come up with stringent national plans on cutting emissions, called nationally determined contributions (NDCs), that are in line with the goal of limiting global temperature rises to 1.5C above preindustrial levels.

Current NDCs, agreed at the Cop26 summit in Glasgow in 2021, are insufficient to hold temperatures within 1.5C of preindustrial levels. Last year was the first to be consistently above 1.5C, and if that trend continues in the longer term the crucial limit will be judged to have been irretrievably breached. The new NDCs will govern emissions for the next decade, so Cop30 represents one of the last chances to put the world on track to avoid irreparable climate breakdown.

Camilla More, a climate diplomacy researcher at the International Institute for Environment and Development thinktank, said: “The world can’t afford to delay any further. That’s why this round of climate targets is critical in changing the course of global efforts to combat climate change.”

Brazil’s president, Luiz Inácio Lula da Silva, has boosted the prospects for Cop30 with two widely welcomed appointments. André Aranha Corrêa do Lago, a veteran climate diplomat, will take on the role of Cop president, and Ana Toni, the government’s climate change secretary, will be executive director of the summit.

The Brazilian president, Luiz Inácio Lula da Silva, (centre) poses with workers during a visit the venue that will host Cop30 in Belém, Brazil. Photograph: Tarso Sarraf/AFP/Getty Images

The two will face a daunting task: Cop29 ended in fierce criticism of the developed world from poor countries, led by India, which denounced the outcome as “abysmally poor”.

Yalchin Rafiyev, the chief negotiator for the Azerbaijani hosts, told the Guardian that his experience of Cop29 made him optimistic for Cop30, as countries should have more common ground in discussions of how to reduce emissions than they had in settling who should pay for it. “Finance [the subject of Cop29] was the most divisive issue,” he said. “If we could manage to get agreement on finance, I am hopeful that we should be able to agree on NDCs.”

Mohamed Adow, the director of the Power Shift Africa thinktank, said the fierce controversies that overshadowed Cop29 need not dog Belém. “There’s a good chance that the rancour and acrimony of Cop29 will be less problematic in Brazil. A large part of the blame was due to the weak Azeri hosts, who mishandled the talks, offended a number of countries and lacked either the diplomatic nous or geopolitical heft to steer talks to a positive outcome,” he said. “The good news is Brazil is much better suited to the job. A progressive leadership, experienced diplomats and one of the great rising forces in geopolitics should result in a much more positive environment.”

Brazil will need powerful allies, however, and with Trump and his many admirers around the world ascendant, there is a dearth of strong leadership on the climate among the biggest economies. Influential countries that have championed climate action in the past are facing fraught elections this year, or internal political crises: in Germany, the coalition led by the chancellor, Olaf Scholz, broke down in the face of a far-right challenge, with elections to be held this weekend; in France, the president, Emmanuel Macron – who convened several climate finance conferences – remains mired in political turmoil; across the EU, rightwing parties are fomenting a backlash against green policy; and in Canada, the previous fragile cross-party consensus on climate action could crumble in the election looming after premier Justin Trudeau’s resignation.

The stance taken by China, which with more than 30% of global emissions is the world’s biggest source of greenhouse gases by some distance, will be crucial. China has a target of peaking emissions by 2030, and reaching net zero by 2060. This is “highly insufficient” and would lead to a world more than 3C hotter than preindustrial levels, according to Climate Action Tracker. With rapidly increasing power generation from renewable sources, and a burgeoning electric vehicle market, the country could do much better.

Piles of coal at a storage facility in Chongqing, south-west China, which produces more than 30% of global emissions. Photograph: AFP/Getty Images

When it does come, China’s NDC needs to be tough if hopes of a 1.5C limit are to be kept alive. “We believe a 30% reduction [in emissions] by 2035, based on an imminent emissions peak of 2025, would be a strong Chinese NDC,” said Li Shuo, the director of the China climate hub at the Asia Society Policy Institute. “This goal will be very challenging, though, in light of the geopolitical environment, as well as China’s domestic economic struggles.”

India, the world’s sixth biggest economy, will also be a key player, with its heavy reliance on coal alongside a rapidly growing renewable energy sector. Arunabha Ghosh, the chief executive of the Council on Energy, Environment and Water, a New Delhi-based thinktank, said: “India must remain steadfast in its commitment to climate action – to capitalise on the strategic opportunities in technology, investment, industrial development, green livelihoods, and greater resilience for the economy. Climate risks are now macroeconomic risks, and climate policy is now industrial policy.”

While many of Europe’s major economies are taking a rightward turn, the exception is the UK, where the prime minister, Keir Starmer, has made shifting to a low-carbon economy one of his key “missions” for government. Starmer is seeking closer relations with China, the US and Europe. He had a 45-minute phone call with Trump days after the inauguration, though climate policy was not discussed. Rachel Reeves, the chancellor of the exchequer, visited China in January, and Ed Miliband, the secretary of state for energy security and net zero, is expected to make a trip to Beijing this year.

Paul Bledsoe, a former Clinton White House climate adviser, now with the American University Center for Environmental Policy, called on the UK to fill the global leadership vacuum left by the “climate nihilism” of the US president. “Given the dearth of EU centre-left leadership, UK leaders like Keir Starmer and Ed Miliband must step forcefully into the void, leveraging relationships with key nations in the global south including Brazil, India, and Kenya,” he said. “This ought to be Britain’s most important Cop since Glasgow.”

Links

• Climate advocacy groups file two lawsuits against Trump administration
• Outrage as Trump cites ‘emergency’ to fast-track fossil fuel projects
• Trump vows to ‘unleash’ oil and gas drilling as he rolls back climate rules
• A ‘recipe for extinction’: can the US’s envied nature protections survive Trump and his ‘God squad’?
• Melting glaciers caused almost 2cm of sea level rise this century, study reveals
• Richest nations ‘exporting extinction’ with demand for beef, palm oil and timber

Heatwave mortality studies reveal climate change impacts and risk for cities - Queensland University

The Heatwave Vulnerability Index research is published in Environmental Impact Assessment Review. The mortality and climate change research was led by ANU’s Professor Sarah Perkins-Kirkpatrick and is published in Environmental Research Climate.

Mortality rates during heatwaves have been put in the spotlight with research from The University of Queensland showing a 20 per cent increase in heatwave-related deaths due to human-induced climate change.

Another UQ study has also revealed people living in cities are at a higher risk of dying from heatwaves than regional areas.

The two studies examined the mortality burden of heatwaves in Australia and Associate Professor Nicholas Osborne from the School of Public Health hopes this research will assist communities and health authorities to prepare for extreme temperature events.

“Our results suggest heatwaves with associated periods of higher mortality will occur more often than they did in the past,” Dr Osborne said.

“These higher mortality rates associated with extreme temperature heatwaves are projected to continue and we hope our research will help communities be better prepared for heatwaves.”

Heatwave risk for those living in cities

In one study, UQ researchers analysed two decades worth of temperature and mortality data to determine which areas in Australia are more vulnerable to heatwaves, through a Heatwave Vulnerability Index.

PhD candidate Patrick Amoatey, from the School of Public Health, said the study – the largest of its kind conducted in Australia – found people living in cities were at higher risk of death during extreme temperature events.

 “We used an index mapping tool to assess how human populations will fare under a range of heat scenarios,” Mr Amoatey said.

“We found the Heatwave Vulnerability Index, frequently used in other countries, could reliably predict heatwave related deaths in Australia.

“In analysing data for more than 2000 suburbs, we found city dwellers with low income, low education, diabetes and limited access to health services, were at the highest risk of heatwave related deaths.

“This was the case for all of Australia’s capital cities, which are home to 70 per cent of Australia’s population.

Afternoon sun setting over
city skyline. Image, Adobe.

‘Heat island effect’

The researchers found that even during low-intensity heatwaves there was a strong association with deaths and the Heatwave Vulnerability Index in Australia’s capital cities.

“We believe the risk is higher in cities because of the ‘heat island effect’, as there are more heat-absorbing surfaces like roads, buildings, and railway lines,” Mr Amoatey said.

“In Greater London, for example, research has shown the Heatwave Vulnerability Index could be used to predict an increase in ambulance callouts and mortality rates during heatwaves, which is helpful for health authorities and something we could use in Australia.

“We already have useful tools and State-based action plans to reduce the impact of heatwaves, but we believe a vulnerability index could help supplement this to help communities plan and build resilience.”

Mr Amoatey said a heatwave was considered a period of 3 consecutive days where the maximum temperature was in the top 5 per cent for that area.

Climate change impacts on heatwave deaths

In a separate study, researchers from UQ and The Australian National University analysed mortality rates during an extreme heatwave in Victoria in January 2009, along with decades of climate data, to examine the impacts of climate change on heat related deaths.

An estimated 374 excess deaths occurred in Victoria during the five-day event, with maximum temperatures reaching 12 – 15 degrees above normal.

“Human-induced climate change had increased the excess heatwave-related mortality in the 2009 event by 20 per cent,” Dr Osborne said.

“These findings were in line with other research that shows heat-related deaths are increasing due to human-induced climate change.

“From a public health perspective, our studies and further research can provide guidance on the need for adequate health infrastructure and workforce that might be needed to cope with higher demand for health services during heatwaves.”

Links

• Heatwave fatalities in Australia, 2001–2018: An analysis of coronial records
• Australia’s deadliest natural disaster you’ve never heard of
• Extreme weather related injuries in Australia over the last decade
• Extreme heat and heatwaves
• Concerns more Australians at risk of heat-related injuries as people do it tough in cost-of-living crisis
• State of the Climate 2024: Australia is enduring harsher fire seasons, more ocean heatwaves and sea-level rise
• Extreme heat fans flames of inequality