Source: The Conversation (Au and NZ) – By Simon Lamb, Associate Professor in Geophysics, Te Herenga Waka — Victoria University of Wellington

You have probably seen the images of the surface of Mars, beamed back by NASA’s rovers. What if there were a time machine capable of roaming Earth during its remote geological past, perhaps even going right back to its beginnings, beaming back pictures of similar quality?

This is not science fiction. In remote corners of the world, geologists have found tiny relics of Earth’s very ancient surface.

I have been part of this scientific endeavour, looking at the treasure trove of information in the bedrock of the Makhonjwa Mountains in South Africa and the adjacent small kingdom of Eswatini.

These rocks reach back more than three quarters of the way through our planet’s long history of nearly 4.6 billion years. In my new book, The Oldest Rocks on Earth, I describe the graphic images “beamed back” by this geological time machine.

World of oceans

The ancient rocks reveal a world with extensive oceans and intense volcanic activity on the sea floor.

Deep beneath the crust, Earth was much hotter than today, giving rise to an unusual white-hot magma, rich in elements from its interior. Huge volumes of super-heated water continually gushed out of underwater cracks, building up chimneys of valuable metals. And life was thriving around these undersea vents.

Volcanic islands rose up from the ocean depths. These were dangerous places. Pools of hot bubbling mud dotted their shores, and clouds of volcanic ash periodically exploded from volcanic craters.

Life was already there, forming microbial mats in the sheltered nearshore waters.

Periodically, large earthquakes violently shook the bedrock, triggering submarine avalanches that cascaded down into the deep ocean, creating vast jumbles of rock on the sea floor. Giant asteroid impacts disturbed this world, but crucially, did not extinguish it.

Deep-seated forces were pushing up new land, creating the early continents.

Ocean waves moved back and forth on sandy beaches along coastlines with bays, lagoons, inlets and estuaries, with tides similar to those today.

During floods, large rivers brought muddy water from the continental interior. Farther in the distance, their headwaters drained a mountainous terrain, often enveloped in thick cloud.

It was a blue planet because, like today, the oceans scattered light in the blue part of the colour spectrum.

But the atmosphere contained a lethal cocktail of gases, including high concentrations of methane and carbon dioxide. These greenhouse gases kept the surface at the right temperature for liquid water, at a time when astrophysicists calculate the Sun was much weaker. But there was no oxygen.

The earliest life forms were anaerobic microbes, although brightly coloured – pink or purple have been proposed.

Oceania today

Oceania, in the southwestern Pacific, may illustrate best what this early world was like. Here, the ocean is peppered with volcanic islands and small continents, rocked by great earthquakes where tectonic plates rub against each other. There are even clues to how life began.

The 2022 eruption of the Hunga volcano, near Tonga, created a mushroom cloud of ash that burst out of the ocean and reached up into space with an estimated energy of a 60-megaton atomic bomb. It generated more than 200,000 lightning strikes and left behind a deep underwater crater filled with a chemical soup derived from numerous underwater hot vents.

Experiments show that lightning strikes can trigger the synthesis of basic organic molecules needed by living organisms. Millions of Hunga-like eruptions on early Earth would have created myriad opportunities to kick start the chemistry of life in underwater volcanic craters – life was born out of extreme geological violence.

Staying blue

Going back in time beyond the Makhonjwa Mountains, we still find evidence for oceans, life and, I argue, plate tectonics. Earth became blue within the first tenth of its history.

Mars and Venus may have started this way, too. But our planet uniquely lies in the so-called Goldilocks Zone, receiving just the right amount of solar energy to avoid becoming a boiling Venusian hell or freezing Martian world.

It is also big enough to have a magnetic field and pull of gravity sufficient to retain its atmosphere. And right at the start, a dramatic collision with a Mars-sized asteroid spalled off our Moon, stabilising Earth’s spin axis so that day and night were less extreme.

Finally, the biochemistry of living organisms may have played a key role in keeping Earth this way by helping the bedrock absorb greenhouse gases in the face of a steadily warming Sun.

We must not be the first to let Earth lose its distinctive life-giving blue, a colour so wonderfully referred to in the Siswati language of Eswatini as luhlata lwesibhakabhaka, literally “green like the sky”.

Simon Lamb has received grants from the UK Natural Environment Research Council which has supported this work. His book ‘The Oldest Rocks on Earth’ is published by Columbia University Press, and he will receive a royalty from sales.

– ref. Ancient African bedrock reveals the violent beginnings of life on our blue planet – https://theconversation.com/ancient-african-bedrock-reveals-the-violent-beginnings-of-life-on-our-blue-planet-268365

Source: The Conversation (Au and NZ) – By Samuel Cornell, PhD Candidate in Public Health & Community Medicine, School of Population Health, UNSW Sydney

Every summer in Australia, millions of people head to the beach, and every year, thousands are rescued by lifeguards or Surf Life Savers and even surfers or other bystanders. Tragically, many people lose their lives on our coasts.

The red and yellow flags, iconic to many Australians, are meant to be a simple and easy to understand message. They denote a safe and patrolled place to go in the water at the beach.

Surfers are supposed to surf outside the flags, while others swim (or wade, or frolic) between the flags.

But for many international visitors, the message is less clear. They may not make sense to people born overseas. Research shows international students often misinterpret what beach flags indicate, rely on visual cues like other swimmers, or assume calm water is safe.

These flags are not universal. Around the world, beach safety is communicated in different ways, with different colours, symbols, messages, and even patrol systems.

Despite the significant efforts of water safety organisations, drowning rates continue to rise in Australia, and people born overseas make up a substantial proportion of these deaths.

The system isn’t working.

What do the flags mean, and why do they matter?

The red and yellow flags have been a part of Australian beach culture and safety since the 1930s. They’ve been marking the patrolled area of the beach ever since.

The idea is that if someone swims between these flags, they are under the watchful eye of professional lifeguards and/or volunteer surf lifesavers.

Usually, the flags are positioned on an area of beach away from rip currents – the fast-flowing, seaward channels of water responsible for an average 26 drownings a year and the vast majority of surf rescues.

But recent studies found that about 70% South Korean university students and 60% Japanese students interpreted the red and yellow flags as indicating a dangerous area.

And a study conducted in the Netherlands showed only 3.4% of surveyed participants correctly interpreted the red and yellow flags. About 40% thought they denoted danger.

These results should be no surprise. Other global safety systems such as road or workplace signs use red to mean danger or prohibition, yellow for caution, and green as safety or permission.

Even half of domestic Australian university students surveyed thought red and yellow flags marked a safe area, so surfers should also stay between the flags. In fact, surfers are not supposed to surf between the flags.

The global picture

Globally, beach flag systems are not standardised.

For instance, in Brazil, Spain, and some areas of the United States, beaches use a traffic-light colour system: green for safe, yellow for caution, and red for danger or closed conditions. Portugal sometimes adds purple flags to warn of marine stingers such as jellyfish.

In some northern parts of Spain, yellow flags are sometimes used to mark designated “cooling off” areas where people are allowed to swim or bathe to cool down, despite red “danger” flags also being in place.

The International Life Saving Federation recommends a global set of eight beach safety flags, including the familiar red-and-yellow for patrolled swimming areas, red for high hazard, yellow for medium hazard, and black-and-white for watercraft zones.

Unlike some countries, the federation explicitly discourages green flags to denote “safe” conditions, on the grounds that no beach or even patrolled area can ever be completely risk-free.

Communicating beach safety

Even if people don’t know what the flag colours mean, in Australia beach signs often say “swim between the flags”.

But research at Bondi Beach in Sydney found that around 30% of overseas-born beachgoers misunderstood this message.

They thought “swim between the flags” meant only people who can actually swim should go there. In other words, if they weren’t good swimmers, they believed they should stay outside the flags.

This is exactly the opposite of what the safety message intends.

Translation tools are not a reliable fix. A recent study found key hazard terms are incorrectly translated by Google Translate.

Take, for example, the term “shore dump” (which means a place where big waves can suddenly break, and “dump” a swimmer underwater). This phrase is currently rendered in simplified Chinese as “岸边垃圾场” (àn biān lèsè chǎng), which means “a place on the shore to dump rubbish”.

“Shore break” (which means the same thing) appears in Korean as “해안 휴식” (haean hyusig), meaning “shore relaxation”. This creates serious risks.

Where to from here?

Redesigning the flags might help.

A recent study conducted in Europe developed and examined a modified version of the red and yellow beach safety flag, incorporating a pictogram of a lifesaver.

This study found adding the pictogram nearly doubled participants’ correct understanding of the flags.

Some experts have also advised that changing “swim between the flags” to “stay between the flags” could improve the translation because “swim” has different connotations in different cultures and languages. Some people might think you should only swim between the flags if you’re a strong swimmer or planning to swim laps.

Simply changing the colours of flags for Australian beaches may not be enough.

The red and yellow flags are tied to a century of lifesaving culture, volunteerism, and community trust. But that legacy shouldn’t stop us from testing whether green flags improve our beach safety communication.

Samuel Cornell receives funding from Meta Platforms, Inc. His research is supported by a University of New South Wales Sydney, University Postgraduate Award. His research is supported by Royal Life Saving Society – Australia to aid in the prevention of drowning. Research at Royal Life Saving Society – Australia is supported by the Australian government. He has been affiliated with Surf Life Saving Australia and Surf Life Saving NSW in a paid and voluntary capacity.

Masaki Shibata receives research funding from Surf Life Saving Australia and is a volunteer surf lifesaver at Tamarama Beach, Sydney, which operates under Surf Life Saving Australia. He has also been collaboratively working on beach signage research with Surf Life Saving Australia and Life Saving Victoria.

– ref. Australia’s red and yellow beach flags can be dangerously confusing. Is it time to change them? – https://theconversation.com/australias-red-and-yellow-beach-flags-can-be-dangerously-confusing-is-it-time-to-change-them-266772

Source: The Conversation (Au and NZ) – By Alex Bellamy, Director of the Asia Pacific Centre for the Responsibility to Protect and Professor of Peace and Conflict Studies, The University of Queensland

By any measure, 2025 was not a good year for world peace.

Worse, it was just the latest of a decade-long decline of peace and upsurge of war.

As author of a book on world peace and how we can achieve it (that’s literally the title), here’s my assessment.

Grim numbers

Peace is on the decline around the world by many measures.

The Armed Conflict Location and Event Data index, a UN-funded independent monitor, reports global conflict has doubled in the past five years.

The International Institute for Security Studies reports a 23% increase in armed conflict in 2025 alone. Approximately 240,000 people were killed by violent conflict in 2025, it reports.

And the Institute for Economics and Peace’s Global Peace Index reported that peacefulness around the world has deteriorated for the sixth consecutive year.

Some of the symptoms of that decline, it reports, include:

• flatlining global trade
• the loss of 42% of government revenue in the developing world to debt interest repayments (the largest global creditor is now China)
• reductions in the amount spent on peacebuilding
• a 42% decline in the number of troops committed to peacekeeping, and
• a dramatic increase in the internationalisation of armed conflict.

War happens when we have rising conflict and declining commitment to the things that produce peace.

Three things are driving those trends:

• the relative decline of liberal democracy and rise of authoritarian powers
• profound shocks such as the global financial crisis and COVID
• problems generated by economic growth based on globalisation, especially rising inequality and social fragmentation.

Nationalist populism in the West and elsewhere is a product of these three transformations, which have unsettled comfortable post-Cold War assumptions about the progress of democracy, wealth, and peace.

We do actually know what drives war and peace

Some may argue that over the long term, the incidence of war and peace ebbs and flows naturally, driven by structural forces that defy human intervention.

But this ignores the immense strides in our understanding of the factors associated with both war and peacefulness.

The forces driving war and peace are not as mysterious as they once were. For example, it is well established that democracy, gender equality, and fair trade are associated with greater peacefulness.

So, it’s perhaps no coincidence that as war increases, each of these social goods are either in decline or are severely challenged.

It is also well established that peacekeeping reduces civilian victimisation, conflict-related sexual violence, and the likelihood of conflict reignition.

Although individual wars have their own specific causes, war and peace, in general, are shaped by a limited set of factors.

Over the past two decades, researchers have done an excellent job identifying what those factors are

We know war is not randomly unpredictable or inexplicable.

This means war is not beyond human control.

War is a choice

The idea that humans are naturally warlike is as facile as the claim that we are naturally peaceful. Anthropologists and biologists have demonstrated we are both.

War is a social practice and like any social practice, is caused by human decisions.

Humans have agency and choice. Certainly, social structures, political ideas and economic pressures influence choices, but they do not determine them.

This is not to say that “war is over, if we want it”.

War occurs because people have serious disagreements about important questions and values – things they cherish so much they would rather fight than compromise.

But peoples, governments and international organisations can create conditions that make war less likely, and the instruments for preventing, limiting, and resolving war more capable.

What is to be done?

International systems are forged by their members.

In the modern international system, that means states. States are primarily responsible for maintaining peace at home – and though some are obviously better than others, by and large, the state has done an excellent job of reducing violence in everyday life.

The building blocks for peace, therefore, lie in the state, especially those that:

• are accountable (democratic)
• respect human rights
• have capable institutions
• provide dignified living and opportunities for all
• foster more gender equal societies.

But this not something that can be changed quickly or easily, and is a political struggle that each society has to undertake on its own terms.

So, it’s wise to focus on rebuilding those international tools we know can make a difference.

3 urgent priorities for the year ahead

First, we must reaffirm international support for the basic principles of the United Nations Charter, including the principal of non-aggression.

In practical terms, this means standing resolutely against aggression and furnishing those who defend themselves against it – notably Ukraine – with every possible support.

Second, we must revive support for UN and regional peacekeeping and peacebuilding efforts and capabilities. Peacekeeping works; more peacekeeping works better. This is especially true when the priority is protection of civilians, women, peace and security.

Third, addressing the gravest crisis of our time: Gaza. To give peace a chance, that means deploying the International Stabilisation Force (the UN-mandated multinational peacekeeping force outlined in the Gaza peace plan).

It must be given every authority and capability necessary to protect civilians, protect Israel from Hamas, and facilitate the extension of legitimate government under the auspices of the Palestinian Authority as a pathway towards Palestinian statehood.

World peace is possible because peace and war are human institutions, not forces of nature.

Even the most deeply ingrained institutions can be reformed. The abolition of slavery was considered impossible until it was achieved.

Yet to say world peace is possible is not to say that it is likely, much less that it is inevitable. But it is something worth studying and striving for. After all, peace is built in the striving.

Alex Bellamy does not currently receive funding from any organisation.

– ref. Is world peace even possible? I study war and peace and here’s where I’d start – https://theconversation.com/is-world-peace-even-possible-i-study-war-and-peace-and-heres-where-id-start-270783

Source: The Conversation (Au and NZ) – By Justin Bergman, International Affairs Editor, The Conversation

In democratic systems, the courts are a vital check on a leader’s power. They have the ability to overturn laws and, in Donald Trump’s case, the executive orders he has relied on to achieve his goals.

Since taking office, Trump has targeted the judiciary with a vengeance. He has attacked what he has called “radical left judges” and is accused of ignoring or evading court orders.

The Supreme Court has already handed the Trump administration some key wins in his second term. But several cases now before the court will be pivotal in determining how much power Trump is able to accrue – and what he’ll be able to do with it.

As Paul Collins, a Supreme Court expert from the University of Massachusetts-Amherst, explains in episode 4 of The Making of an Autocrat:

It’s all about presidential power. And that’s really significant because it’s going to enable the president to basically inject a level of politics into the federal bureaucracy that we frankly haven’t really seen before in the US.

Listen to the interview with Paul Collins at The Making of an Autocrat podcast.

This episode was written by Justin Bergman and produced and edited by Isabella Podwinski and Ashlynne McGhee. Sound design by Michelle Macklem.

Newsclips in this episode from CBS News, The White House, Associated Press, NPR, Spain’s Culture Ministry.

Listen to The Conversation Weekly via any of the apps listed above, download it directly via our RSS feed or find out how else to listen here. A transcript of this episode is available via the Apple Podcasts or Spotify apps.

Paul Collins does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Donald Trump loathes the courts. He’s following the autocrat playbook to sideline them – https://theconversation.com/donald-trump-loathes-the-courts-hes-following-the-autocrat-playbook-to-sideline-them-272270

Source: The Conversation (Au and NZ) – By Thea van de Mortel, Professor Emerita, Nursing, School of Nursing and Midwifery, Griffith University

You’ve been hanging out for a break, getting through the busy last weeks of work or class. You’re finally ready to relax. And then tiredness descends, you feel the tickle in your throat, and you realise you’re getting sick.

Why does this always seem to happen just in time for a holiday or the weekend?

Some call this the let-down effect or leisure sickness.

But is it real? While you may hear about leisure sickness online and anecdotally, studies on this phenomenon are very limited and often not well designed.

So let’s take a look at the evidence – and what you can do to stay healthy.

What the evidence shows

Leisure sickness is a term coined by Dutch researchers in a 2002 study. It refers to people who are seldom ill during the working week but get sick relatively often on weekends or holidays.

The researchers surveyed 1,893 people and found roughly 3% reported leisure sickness. Symptoms typically included headaches, tiredness, colds and flu, muscle pain and nausea. People were more likely to develop infections on vacation rather than weekends, and symptoms were most common during the first week of their holiday.

However, this research relied on people’s recall, and memory can be unreliable. The definition of leisure sickness was also vague. For example, one person’s idea of “seldom” and “relatively often” may differ from another’s.

Another 2014 study investigated “let-down headaches” by asking 22 participants who regularly experienced migraines to keep a diary of their stress levels and migraine onset.

It might seem counter-intuitive, but reducing stress seemed to trigger the migraine. When they recorded a reduction in stress on one day, they typically developed a migraine within the next 24 hours. If work was the stressor, this could mean a pattern of migraines on their days off.

Some evidence suggests strokes are also more common on weekends than weekdays in some groups. There is no clear cause, but the study authors suggested strokes could be triggered by lifestyle changes on weekends.

So, what’s going on?

The lack of quality research on leisure sickness means we don’t fully understand its potential causes. But there are some theories.

People often travel during vacations, and sit in enclosed, crowded spaces such as planes, increasing their exposure to germs. Travel to distant locations can also expose us to strains of germs we’re not immune to.

On holidays we may also drink more alcohol, which can reduce immune function. And we may be pushing our body to do things we don’t normally do, putting stress on it.

Another theory is that being busy at work makes us distracted and less likely to pay attention to symptoms. On leave, symptoms such as muscle pain or a headache may become more obvious – and we can’t blame it on work. So we may notice sickness more.

But isn’t relaxing good for your health?

There is a complicated relationship between stress and the immune system.

Stress activates the sympathetic nervous system and makes our bodies release hormones such as adrenaline and cortisol.

Chronic stress can mean our cortisol levels are sustained at high levels. Over time, this reduces how well our immune cells respond to infection, so we are more likely to get sick if we come into contact with viruses or bacteria.

But in the short term, both adrenaline and cortisol can actually enhance how well some parts of the immune system work. This means acute stress can temporarily improve our resistance to infection, which is why we may feel busy and stressed but not fall sick. Cortisol’s anti-inflammatory properties can also relieve pain.

But when the acute stress stops – for example, when we finally get a chance to rest – there may be a sudden transition. We no longer benefit from the temporary immune boost or cortisol’s pain relief. So this is when we might fall sick, and feel symptoms such as headaches and muscle pain.

How can I avoid getting sick?

There’s still a lot we don’t understand about how or why leisure sickness might happen. But we know staying active, getting enough sleep and eating a healthy, balanced diet – even when you’re busy – can help boost your immune system.

One Finnish study examined more than 4,000 public employees who were physically inactive. It found those who took up regular exercise, particularly vigorous exercise, were less likely to take sick leave than those who remained inactive.

Given the link between chronic stress and multiple chronic diseases, it is also sensible to manage your workplace-related stress.

There is good evidence that meditation, mindfulness and relaxation techniques can help reduce stress.

There are also steps you can take to reduce the risk of respiratory infections on vacation, so you get to enjoy the whole holiday. Consider keeping up to date with flu and COVID boosters, and taking other precautions, such as wearing an N95 mask on planes and in airports.

Thea van de Mortel does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Why do I seem to get sick as soon as I take time off? – https://theconversation.com/why-do-i-seem-to-get-sick-as-soon-as-i-take-time-off-270673

Source: The Conversation (Au and NZ) – By Milad Haghani, Associate Professor and Principal Fellow in Urban Risk and Resilience, The University of Melbourne

January is consistently Australia’s busiest month for moving house – around 14-18% of the yearly total, far higher than any other month.

When people choose a new neighbourhood to live in, there are many factors to weigh up such as price, commute time, school zones and general convenience.

But research shows less obvious aspects of a neighbourhood such as walkability, aircraft noise and tree canopy can measurably improve or worsen daily health and long-term wellbeing. Yet they rarely make it onto anyone’s checklist when choosing where to live.

Here are simple clues to get a sense of how these underrated factors will affect life in a new place.

Walkability

Walkability describes how easily people can reach everyday destinations on foot. It reflects a combination of how well connected streets are, distance to shops and services and how pleasant and practical it is to walk.

A recent study of over two million house moves in the United States found people who relocated to more walkable neighbourhoods took about 1,100 extra steps per day. This level of extra activity is associated with better health by lowering risk of cardiovascular disease, diabetes and early death.

Other studies consistently link walkable areas with better mental health and lower car dependence.

Walkability can vary widely even within the same city and similar price ranges, so it’s worth checking. Two easy tools help assess it:

• the Community Walkability Map run by the Heart Foundation, which estimates which destinations are reachable with a 5–20 minute walk from any address.

• the Australian Urban Observatory, which gives a walkability score to each suburb based on housing density, street connectivity and access to local services. The tool has other liveability indicators and makes it possible to compare between suburbs and against the city average.

Aircraft noise and flight paths

Research shows long-term exposure to aircraft noise can worsen health in several ways.

People living under frequent flight paths have been found to face higher rates of heart disease and poor mental health.

Night-time aircraft noise is linked to sleep disruption, including more awakenings and less deep, restorative sleep.

The noise can also affect children’s learning, with noise exposure associated with poorer attention and reading development when schools sit directly under busy flight corridors.

Most major airports in Australia offer tools to check noise levels for a specific location.

Aircraft noise exposure depends on where flight paths sit, how low planes fly, and how frequently they pass over a neighbourhood.

In Melbourne, residents can access detailed reports for a given address which combine noise-contour maps, flight-path overlays and expected noise levels for individual properties. Other cities don’t have access to this level of detail.

How loud is too loud? At night, a good rule of thumb is that aircraft noise at 55 decibels and up will cause frequent negative effects, such as disturbed sleep and higher health risks. This figure comes from the nighttime noise guidelines issued by the World Health Organization.

Australian aviation guidelines use 70 decibels as the threshold for a “noisy event” likely to disturb indoor activity.

The way a house is designed makes a difference. Double-glazed windows, sealed frames and newer insulation can reduce how noisy it is inside.

If your research suggests a new place may be exposed to aircraft noise, it’s worth checking window quality and insulation.

Tree canopy and urban heat

Tree canopy plays a major role in how hot a neighbourhood feels. Suburbs with fewer trees and less green space absorb and radiate more heat, meaning they are significantly hotter than leafier suburbs. Streets with more trees and shaded surfaces can be 5–10°C cooler on hot days.

Higher local temperatures are linked to greater heat stress, worse sleep during summer nights, and less outdoor activity.

Tree canopy and heat exposure are easy to check. States such as South Australia offer urban heat and tree canopy maps, while Victoria has an Urban Forest visual tool for central Melbourne and less detailed equivalents over a broader metropolitan area.

Using the satellite view on a mapping app can work to give a quick sense of how shaded a street is and whether the surrounding area is dominated by trees, paved surfaces or open, unshaded areas.

Not just nice to have

Many people don’t check how walkable, noisy or leafy an area is before deciding to move there. But these factors have a real impact on quality of life and health.

There’s a broader planning challenge here. More walkable neighbourhoods lead to significantly more walking, aircraft noise worsens sleep and tree canopy can dramatically cool neighbourhoods. This means these issues aren’t just nice to have. They should be thought of as core public health infrastructure.

Connected street networks, reliable shade, quieter residential zones and easy access to daily services should not be luxuries confined to the high-priced areas often coded as “leafy” suburbs in Australia.

Newer developments often lack the mature tree canopy of older suburbs. While it takes time for trees to mature and produce their cooling canopy, this can be sped up with strategic planting of large, spreading trees, consistent irrigation in early years and protection of verge and open-space planting areas. Local planning rules can help by creating tree canopy targets and space for deep-rooted trees.

Similarly, detailed data on aircraft noise should be accessible and easy to interpret in all cities with major airports, not just in Melbourne.

As thousands of Australians prepare to move house this month, it’s a good time to think about what we value in a neighbourhood – and how we could expand access to these desirable attributes.

Planning for walkability, heat resilience and low noise are matters of equity. Healthier urban environments should be available to everyone, not just those who can afford them.

The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

– ref. Moving house? 3 surprising ways your new neighbourhood can affect health and happiness – https://theconversation.com/moving-house-3-surprising-ways-your-new-neighbourhood-can-affect-health-and-happiness-266997

Source: The Conversation (Au and NZ) – By Luke Hartigan, Senior Lecturer in Economics, University of Sydney

When the topic of central banks and the outlook for interest rates comes up, economists often turn to the so-called “star” variables to help with their predictions.

What do we mean by star variables? Why they are important to central bankers, and how do they influence interest-rate decisions?

The star variables relate to key concepts in economic models used by central bankers to help them understand how the economy works.

Star variables are named so simply because they are usually labelled with an asterisk to distinguish them from other variables in economic modelling.

Central bankers don’t normally think about the star variables in isolation. Instead, these variables are better thought of as a “constellation” linking economic growth, the labour market and interest rates together with inflation outcomes.

The three north stars

1. Potential output or y*: This is the economy’s maximum sustainable output that can be produced when all resources are fully employed. It is sometimes referred to as the economy’s speed limit. If economic growth is faster than potential, it can put upward pressure on inflation because demand for goods and services is outstripping supply.

The reverse is also true: if the economy is growing below potential, demand is subdued and inflation will likely fall.

Potential output is closely linked to productivity. Boosting productivity lifts the economy’s speed limit – allowing faster economic growth without fuelling inflation. But falling productivity lowers the economy’s speed limit, meaning it can’t grow as fast as previously without causing inflation to rise. This is the problem currently facing Australia.

2. Non-Accelerating Inflation Rate of Unemployment or NAIRU or u*, a concept that became popular in the 1970s. The idea is there is a “natural” rate of unemployment that doesn’t put pressure on wages or inflation.

3. The neutral interest rate or r* is considered to be the level of the central bank’s key interest rate that is not too low (and stimulating demand) and not too high (and restraining demand). It is a useful guide to the stance of the central bank’s monetary policy, or stance on the policy interest rate.

Good in theory, hard to measure in practice

These three interlinked variables are fundamental to how central bankers think about the economy.

But they are also concepts that are not observable, unlike published statistics on inflation or economic growth. They need to be estimated, and that’s where the uncertainty comes in.

In fact, central bankers must use statistical methods originally developed to track spacecraft to estimate them. This is done by detecting the effects these variables have on other variables that are observable, such as inflation, wages growth and the unemployment rate.

In a recent speech, a US Federal Reserve official wondered whether the three variables are “too abstract and elusive to be of practical value”. He concluded:

The short answer is that they play a central role in macroeconomic theory and have important implications for the conduct of monetary policy.[…] When the stars perfectly align, it means the economy has reached an equilibrium where its resources are fully utilized.

How the variables help with setting interest rates

Most central banks focus on maintaining price stability (low and stable inflation). A few, such as the Reserve Bank of Australia and the US Federal Reserve, have dual mandates to maintain price stability and full employment.

The way central bankers put their objectives into practice is influenced by the star variables. Specifying a target for inflation is seen as the best way to achieve price stability. The Reserve Bank’s target is 2–3% over the economic cycle.

Over time, inflation tends to be steady when the unemployment rate is close to the NAIRU. Because of this, central bankers often use the NAIRU as a rough guide to full employment, which is also broadly consistent with the economy operating near potential.

Understanding the central bank’s objectives is important because they tell us where the economy should go. But they don’t tell us what the central bank will do to get there – that is, what policy interest rate setting is needed to achieve its objectives (what economists call the central bank’s “reaction function”).

This is a way of describing how the central bank adjusts its policy interest rate based on differences between current economic conditions and the star variables.

But this is easier said than done. The uncertainties with estimating the star variables, together with the uncertainties in how interest rate changes flow through the economy, makes it difficult for central bankers to know exactly what decision they should make to achieve their objectives.

All this uncertainty is one reason why central bankers are very cautious. Sometimes it is better to do nothing than make a wrong decision and risk losing credibility.

Luke Hartigan receives funding from the Australian Research Council (DP230100959). He previously worked at the RBA as a Research Economist.

– ref. Why central bankers look to the ‘stars’ when setting interest rates – https://theconversation.com/why-central-bankers-look-to-the-stars-when-setting-interest-rates-270052

Source: The Conversation (Au and NZ) – By Christian Brakenridge, Research Fellow, Iverson Health Innovation Research Institute, Swinburne University of Technology

Recent surveys estimate more than 6.7 million Australians – almost half of all workers, and the majority in Sydney, Melbourne and Canberra – work from home at least some of the time in paid or unpaid roles.

With that increase in working from home, it’s easy to spend too long sitting – which is now recognised as bad for our health. Many of us now know what it feels like to sit at a computer all day, then once finished with work, simply transfer across to the living room couch.

When we have to physically go into our workplace, it’s easier to get incidental activity: from leaving the house, to walking and standing in an active commute, walking to talk to a colleague, go out to get lunch and more.

With many Australians not reaching physical activity guidelines, could we be strategically using an under desk treadmill or walking pad to walk while we work?

How much – and how often – do you really need to walk?

The benefits of walking are now widely substantiated. For instance, studies that have got people to increase their weekly walking have made profound and consistent benefit to health outcomes, such as improving blood pressure and glucose tolerance.

Recent evidence has converged in on 7,000 steps being a target for daily steps when considering prevention of many diseases.

The World Health Organization has also reverted its recommendations from previously saying physical activity must be done in at least 10-minute bouts to “every move counts”, regardless of duration.

Recent experiments back this up too, finding that short, frequent walking or squatting breaks to avoid prolonged sitting can actually have better health outcomes than one bout of walking.

So walking for our health does not need to be performed in a structured and routine way. It can simply be accrued through the day with incidental activity and regular walking breaks.

Together, this evidence suggests that a treadmill at your desk – encouraging regular walking breaks interspersed throughout the day, when you would otherwise be just sitting – would likely be beneficial.

What studies have been done on treadmill desks?

Though there are only a handful of specific studies on the health impacts of office workers using a treadmill desk, they have mostly shown they’re beneficial.

Those studies have found a treadmill desk or walking pad results in changes in fat loss, improving cholesterol, blood pressure and metabolism, with some benefits longer term. But different investigations into their use revealed different results:

• one study found sedentary office workers increased their steps between 1,600 and 4,500 steps per day (with the greatest weight loss among people with obesity), compared to people who weren’t provided a treadmill

• a small study of overweight and obese physicians found they did manage to make using a treadmill work, ending up with 1.9% lower body fat while using the treadmill desk

• another found it led to an increase of 43 minutes of light walking – though workers still reported finding it hard to meet a demanding work schedule to fit that in.

In other words, your mileage may vary! But while these changes may sound small, they are still likely to improve your health, especially when adopted long-term.

Is it too tricky to type?

But how feasible is adding treadmill desks into our workplaces, either at home or in an office?

People may be concerned about the ability to direct attention to walking simultaneously with performing computer-based work.

Interestingly, one study found there weren’t any significant impact to cognitive abilities between those sitting vs walking at their own pace on a treadmill.

However, walking and cycling desks can impair typing and particularly moving a mouse precisely. That makes a treadmill desk less suitable for mouse-intensive work.

For those who find it hard to type accurately while walking, voice-to-text typing options maybe be worth a try. Some are built into computer operating systems, such as in Apple or Chromebook computers.

Try this before you buy

All things considered, treadmill desks are likely to provide a significant contribution to health through changes to physical activity and sedentary behaviours, without much downside.

For some, adding a treadmill desk to your work environment may be the motivator and visual reminder you need to take regular walking breaks – especially if you’re really short on time or do work that makes it hard to leave your desk.

But even the most basic walking pad costs money. You’re looking at around A$180-200 for entry level walking pads, through to $1,000 or more if you want a better treadmill you can also run on. You may also need to invest in a standing desk to be able to work properly.

So before you invest in a whole new desk set up, it’s worth asking: would it be easier and cheaper to simply try regularly walking away from your desk?

Even small changes in physical activity can make a real difference – especially for those who are very sedentary in their work and home life.

Christian Brakenridge does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Walk while you work: are the extra steps on an under desk treadmill worth the cost? – https://theconversation.com/walk-while-you-work-are-the-extra-steps-on-an-under-desk-treadmill-worth-the-cost-264336