Geoengineering - cuckoo clock solutions

Not such a bright idea: cooling the Earth by reflecting sunlight back to space is a dangerous distraction

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James Kerry, James Cook University; Aarti Gupta, Wageningen University, and Terry Hughes, James Cook University

The United Nations Environment Assembly this week considered a resolution on solar radiation modification, which refers to controversial technologies intended to mask the heating effect of greenhouse gases by reflecting some sunlight back to space.

Proponents argue the technologies will limit the effects of climate change. In reality, this type of “geoengineering” risks further destabilising an already deeply disturbed climate system. What’s more, its full impacts cannot be known until after deployment.

The draft resolution initially called for the convening of an expert group to examine the benefits and risks of solar radiation modification. The motion was withdrawn on Thursday after no consensus could be reached on the controversial topic.

A notable development was a call from some Global South countries for “non-use” of solar radiation modification. We strongly support this position. Human-caused climate change is already one planetary-scale experiment too many – we don’t need another.

A risky business

In some circles, solar geoengineering is gaining prominence as a response to the climate crisis. However, research has consistently identified potential risks posed by the technologies such as:

• unpredictable effects on climate and weather patterns

• biodiversity loss, especially if use of the technology was halted abruptly

• undermining food security by, for example, reducing light and increasing salinity on land

• the infringement of human rights across generations – including, but not limited to, passing on huge risks to generations that will come after us.

Here, we discuss several examples of solar radiation modification which exemplify the threats posed by these technologies. These are also depicted in the graphic below.

An infographic showing the effects of solar engineering methods. Authors provided

A load of hot air

In April 2022, an American startup company released two weather balloons into the air from Mexico. The experiment was conducted without approval from Mexican authorities.

The intent was to cool the atmosphere by deflecting sunlight. The resulting reduction in warming would be sold for profit as “cooling credits” to those wanting to offset greenhouse gas pollution.

Appreciably cooling the climate would, in reality, require injecting millions of metric tons of aerosols into the stratosphere, using a purpose-built fleet of high-altitude aircraft. Such an undertaking would alter global wind and rainfall patterns, leading to more drought and cyclones, exacerbating acid rainfall and slowing ozone recovery.

Once started, this stratospheric aerosol injection would need to be carried out continually for at least a century to achieve the desired cooling effect. Stopping prematurely would lead to an unprecedented rise in global temperatures far outpacing extreme climate change scenarios.

Injecting aerosols into the atmosphere may lead to more droughts. Shutterstock

Heads in the clouds

Another solar geoengineering technology, known as marine cloud brightening, seeks to make low-lying clouds more reflective by spraying microscopic seawater droplets into the air. Since 2017, trials have been underway on the Great Barrier Reef.

The project is tiny in scale, and involves pumping seawater onto a boat and spraying it from nozzles towards the sky. The project leader says the mist-generating machine would need to be scaled up by a factor of ten, to about 3,000 nozzles, to brighten nearby clouds by 30%.

After years of trials, the project has not yet produced peer-reviewed empirical evidence that cloud brightening could reduce sea surface temperatures or protect corals from bleaching.

The Great Barrier Reef is the size of Italy. Scaling up attempts at cloud brightening would require up to 1,000 machines on boats, all pumping and spraying vast amounts of seawater for months during summer. Even if it worked, the operation is hardly, as its proponents claim, “environmentally benign”.

The technology’s effects remain unclear. For the Great Barrier Reef, less sunlight and lower temperatures could alter water movement and mixing, harming marine life. Marine life may also be killed by pumps or negatively affected by the additional noise pollution. And on land, marine cloud brightening may lead to altered rainfall patterns and increased salinity, damaging agriculture.

More broadly, 101 governments last year agreed to a statement describing marine-based geoengineering, including cloud brightening, as having “the potential for deleterious effects that are widespread, long-lasting or severe”.

A cloud brightening field trip in 2021 (Southern Cross University)

Balls, bubbles and foams

The Arctic Ice Project involves spreading a layer of tiny glass spheres over large regions of sea ice to brighten its surface and halt ice loss.

Trials have been conducted on frozen lakes in North America. Scientists recently showed the spheres actually absorb some sunlight, speeding up sea-ice loss in some conditions.

Another proposed intervention is spraying the ocean with microbubbles or sea foam to make the surface more reflective. This would introduce large concentrations of chemicals to stabilise bubbles or foam at the sea surface, posing significant risk to marine life, ecosystem function and fisheries.

No more distractions

Some scientists investigating solar geoengineering discuss the need for “exit ramps” – the termination of research once a proposed intervention is deemed to be technically infeasible, too risky or socially unacceptable. We believe this point has already been reached.

Since 2022, more than 500 scientists from 61 countries have signed an open letter calling for an international non-use agreement on solar geoengineering. Aside from the types of risks discussed above, the letter said the speculative technologies detract from the urgent need to cut global emissions, and that no global governance system exists to fairly and effectively regulate their deployment.

Calls for outdoor experimentation of the technologies are misguided and detract energy and resources from what we need to do today: phase out fossil fuels and accelerate a just transition worldwide.

Climate change is the greatest challenge facing humanity, and global responses have been woefully inadequate. Humanity must not pursue dangerous distractions that do nothing to tackle the root causes of climate change, come with incalculable risk, and will likely further delay climate action.

James Kerry, Adjunct Senior Research Fellow, James Cook University, Australia and Senior Marine and Climate Scientist, OceanCare, Switzerland, James Cook University; Aarti Gupta, Professor of Global Environmental Governance, Wageningen University, and Terry Hughes, Distinguished Professor, James Cook University

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

Russia: autocratic rule continues with the loss of Navalny

 

Alexei Navalny had a vision of a democratic Russia. That terrified Vladimir Putin to the core

Robert Horvath, La Trobe University

Alexei Navalny was a giant figure in Russian politics. No other individual rivalled the threat he posed to the Putin regime. His death in an Arctic labour camp is a blow to all those who dreamed he might emerge as the leader of a future democratic Russia.

What made Navalny so important was his decision to become an anti-corruption crusader in 2008. Using shareholder activism and his popular blog, he shone a spotlight on the corruption schemes that enabled officials to steal billions from state-run corporations.

His breakthrough came in 2011, when he proposed the strategy of voting for any party but President Vladimir Putin’s “party of crooks and thieves” in the Duma (parliament) elections. Faced with a collapse of support, the regime resorted to widespread election fraud. The result was months of pro-democracy protests.

Putin regained control through a mix of concessions and repression, but the crisis signalled Navalny’s emergence as the dominant figure in Russia’s democratic movement.

Despite being convicted on trumped-up embezzlement charges, he was allowed to run in Moscow’s mayoral elections in 2013. In a clearly unfair contest, which included police harassment and hostile media coverage, he won 27% of the vote.

Perseverance in the face of worsening attacks

The authorities learned from this mistake. Never again would Navalny be allowed to compete in elections. What the Kremlin failed to stop was his creation of a national movement around the Foundation for the Struggle Against Corruption (FBK), which he had founded in 2011 with a team of brilliant young activists.

During the ensuing decade, FBK transformed our understanding of the nature of Putin’s kleptocracy. Its open-source investigations shattered the reputations of numerous regime officials, security functionaries and regime propagandists.

One of the most important was a 2017 exposé of the network of charities that funded the palaces and yachts of then-premier Dmitry Medvedev. Viewed 46 million times on YouTube, it triggered protests across Russia.

Exposé accusing Dmitry Medvedev of corruption.

No less significant was Navalny’s contribution to the methods of pro-democracy activism. To exploit the regime’s dependence on heavily manipulated elections, he developed a strategy called “intelligent voting”. The basic idea was to encourage people to vote for the candidates who had the best chance of defeating Putin’s United Russia party. The result was a series of setbacks for United Russia in 2019 regional elections.

One measure of Navalny’s impact was the intensifying repression directed against him. As prosecutors tried to paralyse him with a series of implausible criminal cases, they also pursued his family. His younger brother Oleg served three and a half years in a labour camp on bogus charges.

This judicial persecution was compounded by the violence of the regime’s proxies. Two months after exposing Medvedev’s corruption, Navalny was nearly blinded by a Kremlin-backed gang of vigilantes, who sprayed his face with a noxious blend of chemicals.

More serious was the deployment of a death squad from Russia’s Federal Security Service (FSB), which had kept Navalny under surveillance since 2017. The use of the nerve agent Novichok to poison Navalny during a trip to the Siberian city of Tomsk in August 2020 was clearly intended to end his challenge to Putin’s rule.

Instead it precipitated the “Navalny crisis”, a succession of events that shook the regime’s foundations. The story of Navalny’s survival – and confirmation that he had been poisoned with Novichok – focused international attention on the Putin regime’s criminality.

Any lingering doubts about state involvement in his poisoning were dispelled by Navalny’s collaboration with Bellingcat, an investigative journalism organisation, to identify the suspects and deceive one of them into revealing how they poisoned him.

The damage was magnified by Navalny’s decision to confront Putin’s personal corruption. In a powerful two-hour documentary film, A Palace for Putin, Navalny chronicled the obsessive greed that had transformed an obscure KGB officer into one of the world’s most notorious kleptocrats.

With over 129 million views on YouTube alone, the film shattered the dictator’s carefully constructed image as the incarnation of traditional virtues.

A Palace for Putin.

‘We will fill up the jails and police vans’

It is difficult to exaggerate the impact of the “Navalny crisis” on Putin, a dictator terrified of the prospect of popular revolution. No longer was he courted by Western leaders. US President Joe Biden began his term in office in 2021 by endorsing an interviewer’s description of Putin as a “killer”.

To contain the domestic fallout, Putin unleashed a crackdown that began with Navalny’s 2021 arrest on his return to Moscow from Germany, where had been recovering from the Novichok poisoning. On the international stage, Putin secured a summit with Biden by staging a massive deployment of military force on the Ukrainian border, a rehearsal for the following year’s invasion.

The Kremlin’s trolling factories also tried to destroy Navalny’s reputation with a smear campaign. Within weeks of Navalny’s imprisonment, Amnesty International rescinded his status as a “prisoner of conscience” on the basis of allegations about hate speech. The evidence was some ugly statements made by Navalny as an inexperienced politician in the mid-2000s, when he was trying to build an anti-Putin alliance of democrats and nationalists.

What his detractors ignored was Navalny’s own evolution into a critic of ethnonationalist prejudices. In a speech to a nationalist rally in 2011, he had challenged his listeners to empathise with people in the Muslim-majority republics of Russia’s northern Caucasus region.

This divergence from the nationalist mainstream was accentuated by Putin’s conflict with Ukraine. After the invasion of Crimea in March 2014, Navalny denounced the “imperialist annexation” as a cynical effort to distract the masses from corruption.

Eight years later, while languishing in prison, he condemned Putin’s full-scale invasion of Ukraine, exhorting his compatriots to take to the streets, saying:

If, to prevent war, we need to fill up the jails and police vans, we will fill up the jails and police vans.

Later that year, he argued a post-Putin Russia needed an end to the concentration of power in the Kremlin and the creation of a parliamentary republic as “the only way to stop the endless cycle of imperial authoritarianism”.

Navalny’s tragedy is that he never had a chance to convert the moral authority he amassed during years as a dissident into political power. Like Charles de Gaulle in France and Nelson Mandela in South Africa, he might have become a redemptive leader, leading his people from war and tyranny to the promised land of a freer society.

Instead, he has left his compatriots the example of a brave, principled and thoughtful man, who sacrificed his life for the cause of democracy and peace. That is his enduring legacy.

Robert Horvath, Senior lecturer, La Trobe University

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

The risk of ocean change and climate impact

Atlantic Ocean is headed for a tipping point − once melting glaciers shut down the Gulf Stream, we would see extreme climate change within decades, study shows

Too much fresh water from Greenland’s ice sheet can slow the Atlantic Ocean’s circulation. Paul Souders/Stone via Getty Images

René van Westen, Utrecht University; Henk A. Dijkstra, Utrecht University, and Michael Kliphuis, Utrecht University

Superstorms, abrupt climate shifts and New York City frozen in ice. That’s how the blockbuster Hollywood movie “The Day After Tomorrow” depicted an abrupt shutdown of the Atlantic Ocean’s circulation and the catastrophic consequences.

While Hollywood’s vision was over the top, the 2004 movie raised a serious question: If global warming shuts down the Atlantic Meridional Overturning Circulation, which is crucial for carrying heat from the tropics to the northern latitudes, how abrupt and severe would the climate changes be?

Twenty years after the movie’s release, we know a lot more about the Atlantic Ocean’s circulation. Instruments deployed in the ocean starting in 2004 show that the Atlantic Ocean circulation has observably slowed over the past two decades, possibly to its weakest state in almost a millennium. Studies also suggest that the circulation has reached a dangerous tipping point in the past that sent it into a precipitous, unstoppable decline, and that it could hit that tipping point again as the planet warms and glaciers and ice sheets melt.

In a new study using the latest generation of Earth’s climate models, we simulated the flow of fresh water until the ocean circulation reached that tipping point.

The results showed that the circulation could fully shut down within a century of hitting the tipping point, and that it’s headed in that direction. If that happened, average temperatures would drop by several degrees in North America, parts of Asia and Europe, and people would see severe and cascading consequences around the world.

We also discovered a physics-based early warning signal that can alert the world when the Atlantic Ocean circulation is nearing its tipping point.

The ocean’s conveyor belt

Ocean currents are driven by winds, tides and water density differences.

In the Atlantic Ocean circulation, the relatively warm and salty surface water near the equator flows toward Greenland. During its journey it crosses the Caribbean Sea, loops up into the Gulf of Mexico, and then flows along the U.S. East Coast before crossing the Atlantic.

How the Atlantic Ocean circulation changes as it slows. IPCC 6th Assessment Report

This current, also known as the Gulf Stream, brings heat to Europe. As it flows northward and cools, the water mass becomes heavier. By the time it reaches Greenland, it starts to sink and flow southward. The sinking of water near Greenland pulls water from elsewhere in the Atlantic Ocean and the cycle repeats, like a conveyor belt.

Too much fresh water from melting glaciers and the Greenland ice sheet can dilute the saltiness of the water, preventing it from sinking, and weaken this ocean conveyor belt. A weaker conveyor belt transports less heat northward and also enables less heavy water to reach Greenland, which further weakens the conveyor belt’s strength. Once it reaches the tipping point, it shuts down quickly.

What happens to the climate at the tipping point?

The existence of a tipping point was first noticed in an overly simplified model of the Atlantic Ocean circulation in the early 1960s. Today’s more detailed climate models indicate a continued slowing of the conveyor belt’s strength under climate change. However, an abrupt shutdown of the Atlantic Ocean circulation appeared to be absent in these climate models.

How the ocean conveyor belt works.

This is where our study comes in. We performed an experiment with a detailed climate model to find the tipping point for an abrupt shutdown by slowly increasing the input of fresh water.

We found that once it reaches the tipping point, the conveyor belt shuts down within 100 years. The heat transport toward the north is strongly reduced, leading to abrupt climate shifts.

The result: Dangerous cold in the North

Regions that are influenced by the Gulf Stream receive substantially less heat when the circulation stops. This cools the North American and European continents by a few degrees.

The European climate is much more influenced by the Gulf Stream than other regions. In our experiment, that meant parts of the continent changed at more than 5 degrees Fahrenheit (3 degrees Celsius) per decade – far faster than today’s global warming of about 0.36 F (0.2 C) per decade. We found that parts of Norway would experience temperature drops of more than 36 F (20 C). On the other hand, regions in the Southern Hemisphere would warm by a few degrees.

The annual mean temperature changes after the conveyor belt stops reflect an extreme temperature drop in northern Europe in particular. René M. van Westen

These temperature changes develop over about 100 years. That might seem like a long time, but on typical climate time scales, it is abrupt.

The conveyor belt shutting down would also affect sea level and precipitation patterns, which can push other ecosystems closer to their tipping points. For example, the Amazon rainforest is vulnerable to declining precipitation. If its forest ecosystem turned to grassland, the transition would release carbon to the atmosphere and result in the loss of a valuable carbon sink, further accelerating climate change.

The Atlantic circulation has slowed significantly in the distant past. During glacial periods when ice sheets that covered large parts of the planet were melting, the influx of fresh water slowed the Atlantic circulation, triggering huge climate fluctuations.

So, when will we see this tipping point?

The big question – when will the Atlantic circulation reach a tipping point – remains unanswered. Observations don’t go back far enough to provide a clear result. While a recent study suggested that the conveyor belt is rapidly approaching its tipping point, possibly within a few years, these statistical analyses made several assumptions that give rise to uncertainty.

Instead, we were able to develop a physics-based and observable early warning signal involving the salinity transport at the southern boundary of the Atlantic Ocean. Once a threshold is reached, the tipping point is likely to follow in one to four decades.

A climate model experiment shows how quickly the AMOC slows once it reaches a tipping point with a threshold of fresh water entering the ocean. How soon that will happen remains an open question. René M. van Westen

The climate impacts from our study underline the severity of such an abrupt conveyor belt collapse. The temperature, sea level and precipitation changes will severely affect society, and the climate shifts are unstoppable on human time scales.

It might seem counterintuitive to worry about extreme cold as the planet warms, but if the main Atlantic Ocean circulation shuts down from too much meltwater pouring in, that’s the risk ahead.

This article was updated on Feb. 11, 2024, to fix a typo: The experiment found temperatures in parts of Europe changed by more than 5 F per decade.

René van Westen, Postdoctoral Researcher in Climate Physics, Utrecht University; Henk A. Dijkstra, Professor of Physics, Utrecht University, and Michael Kliphuis, Climate Model Specialist, Utrecht University

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

Has the world crossed the 1.5C warming threshold already ?

                                                                                                      Shutterstock

Earlier this week, the media carried a series of articles suggesting that the threshold of limiting increased global temperature to 1.50 C had already been crossed. The articles are based on new research on ocean temperatures that surmised that "hotter land temperatures, together with the earlier onset of industrial-era warming, indicate that global warming was already 1.7 +/- 0.1C above pre-industrial levels by 2020".  In short, this research and possible discovery means that the temperature is 0.5C higher than IPCC estimates with 20  C projected by the late 2020s, nearly two decades earlier than expected.

A team led by Professor Malcolm McCulloch from the University of Western Australia studied 300 years of records preserved in the skeletons of long-lived sea sponges from the Eastern Carribean. Of particular importance the sclerosponge thermometry shows that global warming has already exceeded 1.50 C. The focus of the research was changes in the amount of a chemical known as 'strontium' in the sponges skeletons. The changes in the amount of strontium reflects variations in seawater temperatures over the sponges' life.

The conclusion reached is that the Earth may already have reached at least 1.7C warming since pre-industrial times, well above the Paris Climate target of 1.5C. The opportunity for controlling climate change at the first milestone has already been lost.

Link to Nature article: 300 years of sclerosponge thermometry

Australia Day

Australia Day is meant to provide a formal recognition of the existence of 'Australia' by commemorating the arrival of the First Fleet in 1788 at Sydney Cove and the raising of the Union Jack flag of Great Britain by the first Governor, Arthur Philip. Prior to 1988, Australia Day was quite innocuous with low key celebrations, if any, announcement of public recongition 'honours' recipients and generally it was taken as a public holiday with little fanfare. Re-enactments of the raising of the Flag attracted as few as 200 people at Sydney Cove and the day largely passed without much activity or interest, apart from those going to the beach if the weather was hot.

From the 1988 Bicentenary onward however that changed and Australia Day became the large event it is now and correspondingly increasingly controversial. With this expansion came renewed debate as to the significance of the event and its relative meaning - for the indigenous community it became a constant reminder of the start of the colonisation; for others it retained a connection to Great Britain when Australia was moving into its own cultural identity; for migrants whom did not come from the United Kingdom, it remained a curiosity but little else. So it does raise the question as to whether this is the most apt date to commemorate Australia as a whole or whether such a day is better suited to other significant events such as Federation Day or ANZAC Day both of which have national significance for the country as a whole.

Federation Day commemorates the then six disparate British colonies becoming a single Commonwealth of Australia on 1 January 1901. There is no single answer to the question of the most appropriate date for Australia Day and public opinion polling continues to show a majority of support remains for leaving the current date in place, albeit that this support is less pronounced now than years ago.  

COVID evolution

The emergence of JN.1 is an evolutionary ‘step change’ in the COVID pandemic. Why is this significant?

Lightspring/Shutterstock

Suman Majumdar, Burnet Institute; Brendan Crabb, Burnet Institute; Emma Pakula, Burnet Institute, and Stuart Turville, UNSW Sydney

Since it was detected in August 2023, the JN.1 variant of COVID has spread widely. It has become dominant in Australia and around the world, driving the biggest COVID wave seen in many jurisdictions for at least the past year.

The World Health Organization (WHO) classified JN.1 as a “variant of interest” in December 2023 and in January strongly stated COVID was a continuing global health threat causing “far too much” preventable disease with worrying potential for long-term health consequences.

JN.1 is significant. First as a pathogen – it’s a surprisingly new-look version of SARS-CoV-2 (the virus that causes COVID) and is rapidly displacing other circulating strains (omicron XBB).

It’s also significant because of what it says about COVID’s evolution. Normally, SARS-CoV-2 variants look quite similar to what was there before, accumulating just a few mutations at a time that give the virus a meaningful advantage over its parent.

However, occasionally, as was the case when omicron (B.1.1.529) arose two years ago, variants emerge seemingly out of the blue that have markedly different characteristics to what was there before. This has significant implications for disease and transmission.

Until now, it wasn’t clear this “step-change” evolution would happen again, especially given the ongoing success of the steadily evolving omicron variants.

JN.1 is so distinct and causing such a wave of new infections that many are wondering whether the WHO will recognise JN.1 as the next variant of concern with its own Greek letter. In any case, with JN.1 we’ve entered a new phase of the pandemic.

Where did JN.1 come from?

The JN.1 (or BA.2.86.1.1) story begins with the emergence of its parent lineage BA.2.86 around mid 2023, which originated from a much earlier (2022) omicron sub-variant BA.2.

Chronic infections that may linger unresolved for months (if not years, in some people) likely play a role in the emergence of these step-change variants.

In chronically infected people, the virus silently tests and eventually retains many mutations that help it avoid immunity and survive in that person. For BA.2.86, this resulted in more than 30 mutations of the spike protein (a protein on the surface of SARS-CoV-2 that allows it to attach to our cells).

The sheer volume of infections occurring globally sets the scene for major viral evolution. SARS-CoV-2 continues to have a very high rate of mutation. Accordingly, JN.1 itself is already mutating and evolving quickly.

How is JN.1 different to other variants?

BA.2.86 and now JN.1 are behaving in a manner that looks unique in laboratory studies in two ways.

The first relates to how the virus evades immunity. JN.1 has inherited more than 30 mutations in its spike protein. It also acquired a new mutation, L455S, which further decreases the ability of antibodies (one part of the immune system’s protective response) to bind to the virus and prevent infection.

The second involves changes to the way JN.1 enters and replicates in our cells. Without delving in to the molecular details, recent high-profile lab-based research from the United States and Europe observed BA.2.86 to enter cells from the lung in a similar way to pre-omicron variants like delta. However, in contrast, preliminary work by Australia’s Kirby Institute using different techniques finds replication characteristics that are aligned better with omicron lineages.

Further research to resolve these different cell entry findings is important because it has implications for where the virus may prefer to replicate in the body, which could affect disease severity and transmission.

Whatever the case, these findings show JN.1 (and SARS-CoV-2 in general) can not only navigate its way around our immune system, but is finding new ways to infect cells and transmit effectively. We need to further study how this plays out in people and how it affects clinical outcomes.

Is JN.1 more severe?

JN.1 has some characteristics which distinguish it from other variants. Elizaveta Galitckaia/Shutterstock

The step-change evolution of BA.2.86, combined with the immune-evading features in JN.1, has given the virus a global growth advantage well beyond the XBB.1-based lineages we faced in 2023.

Despite these features, evidence suggests our adaptive immune system could still recognise and respond to BA.286 and JN.1 effectively. Updated monovalent vaccines, tests and treatments remain effective against JN.1.

There are two elements to “severity”: first if it is more “intrinsically” severe (worse illness with an infection in the absence of any immunity) and second if the virus has greater transmission, causing greater illness and deaths, simply because it infects more people. The latter is certainly the case with JN.1.

What next?

We simply don’t know if this virus is on an evolutionary track to becoming the “next common cold” or not, nor have any idea of what that timeframe might be. While examining the trajectories of four historic coronaviruses could give us a glimpse of where we may be heading, this should be considered as just one possible path. The emergence of JN.1 underlines that we are experiencing a continuing epidemic with COVID and that looks like the way forward for the foreseeable future.

We are now in a new pandemic phase: post-emergency. Yet COVID remains the major infectious disease causing harm globally, from both acute infections and long COVID. At a societal and an individual level we need to re-think the risks of accepting wave after wave of infection.

Altogether, this underscores the importance of comprehensive strategies to reduce COVID transmission and impacts, with the least imposition (such as clean indoor air interventions).

People are advised to continue to take active steps to protect themselves and those around them.

For better pandemic preparedness for emerging threats and an improved response to the current one it is crucial we continue global surveillance. The low representation of low- and middle- income countries is a concerning blind-spot. Intensified research is also crucial.

Suman Majumdar, Associate Professor and Chief Health Officer - COVID and Health Emergencies, Burnet Institute; Brendan Crabb, Director and CEO, Burnet Institute; Emma Pakula, Senior Research and Policy Officer, Burnet Institute, and Stuart Turville, Associate Professor, Immunovirology and Pathogenesis Program, Kirby Institute, UNSW Sydney

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

The warming of Antarctica

DM Bergstrom, Author provided

A heatwave in Antarctica totally blew the minds of scientists. They set out to decipher it – and here are the results

Dana M Bergstrom, University of Wollongong

Climate scientists don’t like surprises. It means our deep understanding of how the climate works isn’t quite as complete as we need. But unfortunately, as climate change worsens, surprises and unprecedented events keep happening.

In March 2022, Antarctica experienced an extraordinary heatwave. Large swathes of East Antarctica experienced temperatures up to 40°C (72°F) above normal, shattering temperature records. It was the most intense heatwave ever recorded anywhere in the world.

So shocking and rare was the event, it blew the minds of the Antarctic climate science community. A major global research project was launched to unravel the reasons behind it and the damage it caused. A team of 54 researchers, including me, delved into the intricacies of the phenomenon. The team was led by Swiss climatologist Jonathan Wille, and involved experts from 14 countries. The collaboration resulted in two groundbreaking papers published today.

The results are alarming. But they provide scientists a deeper understanding of the links between the tropics and Antarctica – and give the global community a chance to prepare for what a warmer world may bring.

Head-hurting complexity

The papers tell a complex story that began half a world away from Antarctica. Under La Niña conditions, tropical heat near Indonesia poured into the skies above the Indian Ocean. At the same time, repeated weather troughs pulsing eastwards were generating from southern Africa. These factors combined into a late, Indian Ocean tropical cyclone season.

Between late February and late March 2022, 12 tropical storms had brewed. Five storms revved up to become tropical cyclones, and heat and moisture from some of these cyclones mashed together. A meandering jet stream picked up this air and swiftly transported it vast distances across the planet to Antarctica.

Below Australia, this jet stream also contributed to blocking the eastward passage of a high pressure system. When the tropical air collided with this so-called “blocking high”, it caused the most intense atmospheric river ever observed over East Antarctica. This propelled the tropical heat and moisture southward into the heart of the Antarctic continent.

Luck was on Antarctica’s side

The event caused the vulnerable Conger Ice Shelf to finally collapse. But the impacts were otherwise not as bad as they could have been. That’s because the heatwave struck in March, the month when Antarctica transitions to its dark, extremely cold winter. If a future heatwave arrives in summer – which is more likely under climate change – the results could be catastrophic.

Despite the heatwave, most inland temperatures stayed below zero. The spike included a new all-time temperature high of -9.4°C (15.1°F) on March 18 near Antarctica’s Concordia Research Station. To understand the immensity of this, consider that the previous March maximum temperature at this location was -27.6°C (-17.68°F). At the heatwave’s peak, 3.3 million square kilometres in East Antarctica – an area about the size of India – was affected by the heatwave.

The impacts included widespread rain and surface melt along coastal areas. But inland, the tropical moisture fell as snow – lots and lots of snow. Interestingly, the weight of the snow offset ice loss in Antarctica for the year. This delivered a temporary reprieve from Antarctica’s contribution to global sea-level rise.

These images, acquired by the Copernicus Sentinel-2 satellites on January 30 2022 (left) and March 21 2022 (right), show the Conger ice shelf before and after the collapse, which was triggered by a shocking heatwave. European Union, Copernicus Sentinel-2 satellite imagery, CC BY

Learning from the results

So what are the lessons here? Let’s begin with the nice bit. The study was made possible by international collaboration across Antarctica’s scientific community, including the open sharing of datasets. This collaboration is a touchstone of the Antarctic Treaty. It serves as a testament to the significance of peaceful international cooperation and should be celebrated.

Less heartwarmingly, the extraordinary heatwave shows how compounding weather events in the tropics can affect the vast Antarctic ice sheet. The heatwave further reduced the extent of sea ice, which was already at record lows. This loss of sea ice was exacerbated this year resulting in the lowest summer and winter sea ice ever recorded. It shows how disturbances in one year can compound in later years.

The event also demonstrated how tropical heat can trigger the collapse of unstable ice shelves. Floating ice shelves don’t contribute to global sea-level rise, but they acts as dams to the ice sheets behind them, which do contribute.

This research calculated that such temperature anomalies occur in Antarctica about once a century, but concluded that under climate change, they will occur more frequently.

The findings enable the global community to improve its planning for various scenarios. For example, if a heatwave of similar magnitude hit in summer, how much ice melt would there be? If an atmospheric river hit the Doomsday glacier in the West Antarctic, what rate of sea level rise would that trigger? And how can governments across the world prepare coastal communities for sea level rise greater than currently calculated?

This research contributes another piece to the complex jigsaw puzzle of climate change. And reminds us all, that delays to action on climate change will raise the price we pay.

This article has been amended to correct an error in converting a 40°C temperature difference from Celsius to Fahrenheit.

Dana M Bergstrom, Honorary Senior Fellow, University of Wollongong

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