Category: English

Source: The Conversation – UK – By Vikram Niranjan, Assistant Professor in Public Health, School of Medicine, Health Research Institute, University of Limerick

Cruises are sold as floating holidays, but they are also useful for understanding public health. Cruise ships are carefully designed places where many people live, eat, relax and move through the same shared spaces for days at a time. They show how easily illness can spread when people are packed into a single interconnected environment.

Think of a cruise ship as a temporary city at sea. It has restaurants, theatres, lifts, cabins, kitchens, water systems and indoor gathering spaces. That is great for convenience, but it also means that once an infection gets on board, it can move through the ship in ways that are hard to stop.

The Diamond Princess outbreak is perhaps the best-known example. During the 2020 COVID outbreak, 619 passengers and crew tested positive for the disease. Researchers found that the ship conditions made the novel coronavirus spread more easily. Their modelling suggested that public health measures, such as isolation and quarantine, prevented many more cases, but it also showed that an earlier response would have further limited the outbreak.

Norovirus (the so-called vomiting bug) is the infection most closely linked to cruise ships. In a review of previously published studies, researchers found 127 reports of norovirus outbreaks on cruise ships, with many linked to contaminated food, contaminated surfaces and person-to-person spread. A more recent report from the US also showed that norovirus can spread very rapidly from person to person on a cruise ship.

This helps explain why ships such as Celebrity Mercury, Explorer of the Seas and Carnival Triumph have become familiar names in outbreak reports. These were not unusual in some special way; they were simply settings where shared dining, close contact and frequent movement through common areas allowed infection to spread fast.

Food service plays a big part in this risk. Buffet-style dining, shared utensils and many people touching the same surfaces can make it easier for stomach bugs to spread. If someone is infected but does not yet feel sick, they may still contaminate food or surfaces before they realise they are unwell.

The ship’s design adds to the problem. People spend time together in dining rooms, bars, lifts, corridors, theatres and spa areas. Crew members also live and work in the same environment, often in shared accommodation, so illness can move through the ship from passenger to passenger or between passengers and crew.

Ventilation also plays a crucial role. Cruise ships are not closed boxes, but they do rely heavily on indoor spaces where people spend long periods together. Studies into cruise ship air quality have shown that illness can spread more easily in crowded, enclosed spaces, like cabins, restaurants and entertainment venues, if the ventilation system is not up to scratch. Things like adequate fresh air circulation, specialist filters and air-purifying technology all play a role in keeping passengers safe.

Legionnaires’ disease (a serious lung disease caused by bacteria) shows a different kind of risk. It is not usually spread directly from one person to another. Instead, people can get infected by breathing in tiny droplets from contaminated water systems, hot tubs or showers.

A well-known outbreak among cruise passengers was linked to a whirlpool spa, and recent reports from the US Centers for Disease Control and Prevention have described other cruise-associated legionnaires’ disease outbreaks linked to ship water systems.

Age also matters. Cruise holidays are especially popular with older adults, and many passengers have long-term health conditions that make infections more serious. A stomach bug on a cruise can lead to dehydration, and a respiratory infection can lead to pneumonia or hospital care.

Cruise ships do have medical facilities, but they are limited compared with land-based hospitals. They are built to give first aid, basic treatment and short-term care, not to manage a fast-moving outbreak on a large scale. That is why cruise health depends so much on early reporting, quick isolation and strong cleaning practices.

Other infections such as respiratory viruses, including influenza, can spread in the same crowded indoor settings, and stomach bugs can spread through food, hands and shared surfaces. COVID and flu exploit enclosed air and crowds. Norovirus loves buffets and surfaces. Legionnaires’ targets water systems, which ships can’t easily sterilise. Hantavirus (a severe respiratory illness spread by rodents) outbreaks on ships are rare. However, as recent news of the deaths on the MV Hondius attests, germs in close quarters find it much easier to spread.

How to limit your risk

As an epidemiologist, I have seen many outbreaks in hospitals, schools and even flights. For travellers, the best protection starts before boarding. It is sensible to check whether the cruise line has clear illness reporting, cleaning and isolation policies. Make sure your routine vaccines are up to date. And for older adults, pregnant women and anyone with health problems, consult your GP before travelling. Also, ensure your travel insurance covers illness-related disruptions.

Once on board, washing your hands with soap and water is the most useful step for preventing stomach bugs like norovirus. Hand sanitiser can help, but it does not replace soap and water. If you start to feel unwell, the safest move is to avoid buffets and crowded shared spaces and report symptoms early rather than trying to carry on as normal.

Cruise lines have improved their hygiene and outbreak response systems over time, and many voyages pass without incident. But the basic structure of cruise travel still creates the same challenge: many people sharing the same meals, the same air, the same water systems and the same common spaces. That is why outbreaks keep returning, and why cruise ships remain a useful reminder that public health is shaped as much by design as by germs.

Vikram Niranjan 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. Hantavirus, COVID, norovirus, legionnaires’: why are cruise ships so prone to disease outbreaks? – https://theconversation.com/hantavirus-covid-norovirus-legionnaires-why-are-cruise-ships-so-prone-to-disease-outbreaks-282121

Source: The Conversation – UK – By Audrey Morley, Lecturer in Physical Geography, University of Galway

For generations, the mild and temperate climate of north-western Europe has been credited to one legendary force: the Gulf Stream. This idea is so deeply entrenched in our cultural identity that in James Joyce’s Ulysses, the protagonist Stephen Dedalus refuses to take a bath, arguing that “all Ireland is washed by the Gulf Stream”.

However, the Gulf Stream is just one part of a much more complex system called the Atlantic Meridional Overturning Circulation or AMOC.

To explain this better, scientists often use the image of a giant ocean conveyor belt, where warm waters move northwards across the surface of the Atlantic from the tropics. As these waters reach the North Atlantic, they release their heat into the atmosphere, much like a radiator. The AMOC also carries the moisture that gives us our temperate landscape. After the waters have released their heat, they become colder and denser, which makes them sink into the deep ocean. These waters then return southward, at great depths.

When scientists talk about the AMOC “slowing down” or “changing,” they are essentially describing a reduction in the strength of our natural radiator. Specifically, they measure how much water is moving north and south at different depths across the Atlantic. This allows them to estimate how much heat is being carried from the tropics toward the North Atlantic and back again at depth.

More than a conveyor belt

Although this “conveyor belt” analogy is a helpful starting point, modern research suggests it is incomplete and potentially misleading. For example, the system is incredibly sensitive to how seawater changes its weight and density as it interacts with the atmosphere, freshwater, ice and incoming solar radiation. Because of these additional processes, the AMOC behaves less like a single, steady loop and more like a network of interconnected regional components.

Different parts of the system can change independently, sometimes with only regional effects and sometimes with consequences for the entire system.

The Subpolar Gyre (SPG), a system of wind-driven ocean currents occupying the region from the Labrador Sea to the west of Ireland, is a powerful example of why the network perspective matters. This regional AMOC component can show a significant degree of independence from the global AMOC. It is controlled by local winds and pulses of freshwater, linked to changes in sea-ice.

Crucially for those of us in Ireland and the UK, a sudden weakening of the SPG could trigger abnormally cold winter weather, similar to conditions seen during the “little ice age”. This period of intense regional cooling, which lasted roughly from the early 14th century to the mid-19th century, was characterised by winters so severe that the River Thames froze over.

Scientific research suggests that this cold period was likely sustained and amplified by a regional change in the SPG while the AMOC remained relatively stable. This means we could face local climate shifts, including increased storminess and colder winters, because of a “flicker” in our regional component of the AMOC network, long before the entire global circulation reaches a tipping point.

This is why scientists are now focused on identifying early warning signs of instability within the AMOC.

Are there signs that the AMOC has already begun to change? While climate models agree that it is likely that the AMOC will destabilise this century due to global warming, direct scientific observations of the AMOC are still too short to give us a definitive answer.

Networks of monitoring tools like Rapid or OSNAP that measure the transport of water both at depth and at the surface have only been in place for about 20 years. In the life of a massive ocean system, this is just a heartbeat. Scientists estimate we may need 30 to 40+ years of continuous observations to clearly detect a long-term AMOC decline against the ocean’s natural variability.

Why does it matter?

For generations, societies, economies and infrastructures in north-western Europe have been built around a stable, mild and wet climate. If this natural radiator fails or even significantly weakens the consequences will ripple across Ireland, the UK and the European continent.

We should care about this because the AMOC currently moves a massive amount of heat
from the tropics to the North Atlantic, where it is released into the atmosphere. A weakening of this system means that a portion of this tropical warmth is no longer delivered to our region as effectively, leading to cooling across northwestern Europe.

While Hollywood depicted a sudden ice age in the film The Day After Tomorrow (2004), the scientific reality of a slowdown is no less concerning. We could face significantly colder winters resulting in more frequent harsh freezes, snow and severe frosts. During the little ice age a weaker SPG led to agricultural failures and famines. We could also experience an increase in storminess shifting rainfall patterns, and drier summers, all of which could damage critical infrastructures like roads and crop harvests.

The AMOC is also essential for keeping carbon and heat stored in the deep ocean, effectively locking it away from the atmosphere. At the moment the world’s oceans absorb approximately 25-30% of all human-made carbon dioxide emissions each year.

However, should the AMOC slow down it is expected that the rate at which carbon is stored in the deep ocean also slows down. The AMOC also redistributes the nutrients that sustain marine ecosystems. A disruption here wouldn’t just change our weather; it would weaken the ocean’s ability to act as a carbon sink, potentially accelerating global warming in a dangerous feedback loop.

Keeping an eye on the AMOC is a matter of national and regional security.

Whether the decline is gradual or approaches a tipping point, the impact on our way of life will be profound. By listening to the signals coming from the deep ocean today, we can better prepare for the climate of tomorrow.

Audrey Morley receives funding from Research Ireland, The Marine Institute, The Department of Foreign Affairs and Trade (Ireland) and the Geological Survey of Ireland

– ref. The ocean system that shapes Europe’s climate – https://theconversation.com/the-ocean-system-that-shapes-europes-climate-281056

Source: The Conversation – UK – By Trudy Meehan, Lecturer, Centre for Positive Psychology and Health, RCSI University of Medicine and Health Sciences

The key to better wellbeing is acting like an Italian grandmother, according to social media’s “nonnamaxxing” trend.

Proponents of the trend say that adopting the lifestyle habits of an Italian nonna will help improve your health and mental wellbeing. The core principles of the trend are simple: make time for your friends and loved ones, eat foods grown from your own garden and cook hearty meals at home.

This latest trend borrows from lifestyle medicine research which shows the same practices being advocated by nonnamaxxing enthusiasts can not only add years to your life, but add life to your years.

No one’s 20s and 30s look the same. You might be saving for a mortgage or just struggling to pay rent. You could be swiping dating apps, or trying to understand childcare. No matter your current challenges, our Quarter Life series has articles to share in the group chat, or just to remind you that you’re not alone.

So instead of jumping on the nonnamaxxing bandwagon until the next trend rolls around, here are some examples of how you can adopt these habits for life.

Positive social connections

A core tenet of “nonnamaxxing” is making time for friends and loved ones.

Research shows maintaining positive social connections is one of the most helpful factors in supporting health across your lifespan. Social experiences help us regulate emotionally. Not only does this impact our happiness and wellbeing, it also has a whole host of other physiological benefits.

For instance, laughing with our loved ones or holding their hand reduces pain and dampens the stress response. Research also shows social connection can reduce inflammation and improve immune responses.

This doesn’t mean you need to rush out and get married – it’s not just about romantic relationships. Relationships come in many forms. Even micro-moments of positive social interaction – such as having a brief chat with a barista – have measurable health and wellbeing benefits. Research has also found that people who volunteer have a lower risk of catching the common cold.

Collective experiences such as concerts, rituals, dancing, singing or cheering together can also generate “collective effervescence” – a feeling of unity, aliveness and belonging.

When we interact in person, our brains and bodies synchronise with that person in a way that feels good, supports connection and supports health. We feel a greater sense of purpose, belonging and self-worth.

Try gardening

Physical activity and moving every day are among key factors that have been linked with longevity.

But this doesn’t mean you need to hit the gym or go running to see benefits. Even gardening, an activity we might typically associated with an Italian nonna’s lifestyle, has been associated with health benefits.

Gardening is a physically stimulating activity that translates into increased mobility and reduced sedentary behaviour. Reviews also show it’s good for mental health and quality of life.

Due to its multimodal nature, gardening stimulates the brain. We need to plan, coordinate, remember to remember and monitor changes in our garden over time. This type of stimulation supports the development of cognitive reserve – additional healthy brain tissue that helps offset the functional impairments of diseased brain matter as we age. This may explain why activities such as gardening are associated with lower likelihood of being diagnosed with dementia.

Home-cooked meals

Another core tenet of nonnamaxxing is cooking meals at home.

The more frequently you cook at home, the better. Those who cook their own meals tend to have a higher intake of fruit, vegetables and fiber. Cooking at home also means you tend to consume fewer calories, fats and added sugar, which may help regulate blood sugar, reduce body fat and prevent type 2 diabetes.

In the field of positive psychology, cooking is described as an activity that captures key parts of what makes us happy – such as positive emotions and a sense of meaning and accomplishment.

How to get started

If you’re keen to give nonnamaxxing a try, here are a few easy ways to be more like an Italian nonna in your everyday life.

We all know by now that socialising and meeting friends and family is good for us, but if you can’t get together in person make use of technology.

Although technology isn’t quite as good as real-life interactions, try making these interactions intentional when they do happen. Being emotionally responsive, engaged and letting your loved one know you’re there – even while texting – can increase connection and warmth.

And when contacting friends or family, try to call – or at least send a voice message. Social interactions using our voices create stronger social connection compared to text-based interactions.

To give gardening a try, start with something small that grows easily. Even if it’s just a small tomato or strawberry plant you can put on your windowsill. This will give you a sense of purpose, and you’ll be able to enjoy the fruits of your labour, too, which is good for your health.

If you don’t want the responsibility of a garden, getting outside and being in nature – especially in parks or near rivers – will boost both physical activity levels and improve health and wellbeing.

As for cooking your meals at home, don’t feel like you need to start with a complicated recipe. Start with making sandwiches or even snacks and build up to cooking a dinner. Remember, cooking is a skill; you can learn by following a recipe or cooking video.

If you don’t have the time to cook, try eating with someone. Eating together boosts social connection and provides a sense of safety and belonging. If you don’t have anyone to eat with, try picking a food or meal that reminds you of a loved one. This food nostalgia can reproduce feelings of warmth and connection.

While the nonnamaxxing trend may be forgotten in a week, it describes a way of living that’s generations old. Living like an Italian grandma hasn’t just passed the test of time, it’s been tested by health and wellbeing researchers too.

Trudy Meehan 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. TikTok’s ‘nonnamaxxing’ trend explained: here’s how living like an Italian grandma can benefit health and wellbeing – https://theconversation.com/tiktoks-nonnamaxxing-trend-explained-heres-how-living-like-an-italian-grandma-can-benefit-health-and-wellbeing-281073

Source: The Conversation – UK – By Keighley Perkins, Research Associate School of Journalism, Media and Culture, Cardiff University; Swansea University

Voters in Wales will soon go to the polls to elect members of an expanded Senedd (Welsh parliament) under a new proportional voting system. As the campaign has developed, public service broadcasters have sought not only to report events but to educate, inform and engage audiences with an unfamiliar electoral process.

Our analysis suggests they are increasingly doing so through digital platforms. We analysed all election news content produced online and on social media by major broadcasters between April 8 and April 24, including BBC Wales, ITV Wales, S4C, Channel 4 and Sky News.

The findings point to a move towards formats designed for audiences who are more likely to encounter news online than through traditional television.

This matters because people increasingly come across political content passively, through algorithmically curated feeds rather than actively seeking it out. In that environment, the type of content produced – and how it’s presented – can play a decisive role in shaping public understanding of the election.

One prominent feature of digital coverage has been the use of explainers. These aim to demystify the election by breaking down how the Senedd works, how the voting system has changed and which policy areas are devolved to Wales or reserved to Westminster.

Many of these explainers adopt a more informal and accessible tone than their broadcast equivalents. They’re designed to cut through in fast-moving social media feeds where political information competes for attention.

A significant proportion focus on policy. Of the 19 explainers identified in our analysis, seven centred on specific issues, most commonly immigration. This reflects persistent public confusion about where responsibility lies.

Read more:
Voters in Wales face Senedd election amid confusion over who holds power over what

Our recent survey found that nearly a third of people in Wales did not know immigration is controlled by the UK government. Against that backdrop, broadcasters have often made this distinction explicit. In 82% of online and social media items mentioning immigration, journalists clearly stated that responsibility lies with Westminster.

Broadcasters have also used explainers to clarify changes to the electoral system. This includes the move to a closed-list proportional system. Public awareness of this change remains low, however. Only 7% of respondents in our survey correctly identified the system, while 58% said they did not know.

Meet the leaders

Alongside explainers, broadcasters have used digital formats to introduce audiences to the leaders of Wales’s six main political parties. This has reinforced the campaign’s increasingly presidential tone, with party leaders dominating media appearances.

In a devolved context, this is not always straightforward, given the presence of both UK-wide and Welsh political figures. But digital formats have provided new ways to foreground Welsh leaders.

Short, one-to-one interviews have become an important feature. Formats such as the BBC’s Quickfire Questions and ITV’s Chippy Chats mix light-touch prompts – like “What song have you got on repeat?” – with more substantive questions about policy priorities.

These formats inject personality into political coverage. Leaders are presented not only as decision-makers but as people with interests and personalities. This is particularly significant given relatively low public awareness of Welsh political figures.

Our recent survey found that fewer than half of respondents could identify the leader of Plaid Cymru, Rhun ap Iorwerth, despite the fact he could become the next first minister.

At the same time, the informal tone has not entirely displaced scrutiny. In ITV’s Chippy Chats for example, the Welsh Liberal Democrat leader Jane Dodds was challenged on her voting record in the Senedd. It’s a reminder that accountability can still be built into more conversational formats.

Informing voters in a digital campaign

Taken together, these approaches suggest broadcasters are using digital platforms in distinct and complementary ways. Explainers aim to address gaps in public knowledge. One-to-one interviews make political leaders more visible and relatable.

This reflects a broader transformation in how election coverage is produced and consumed. As more people encounter political information online, public service broadcasters play an increasingly important role in countering misinformation and improving understanding of politics and public affairs.

The challenge is now to strike the right balance. Broadcasters must produce content that engages audiences. But they shouldn’t lose sight of the need to inform them and to scrutinise the claims made by political parties.

Keighley Perkins receives funding from AHRC for research into broadcasters’ impartiality.

Maxwell Modell receives funding from the AHRC for research into broadcasters’ impartiality.

Stephen Cushion has received funding from the BBC Trust, Ofcom, AHRC, BA, ESRC and Welsh Government.

– ref. Welsh broadcasters target voters with digital election coverage – https://theconversation.com/welsh-broadcasters-target-voters-with-digital-election-coverage-281821

Source: The Conversation – UK – By Zihan Wang, Research Fellow in Geography and Innovation, University of Sussex

Co-working spaces have become a familiar part of the working landscape. A convenient alternative to working from home or an employer’s office, they have become the favoured option of millions of the world’s freelancers, entrepreneurs and remote workers.

In the UK, there are over 4,000 co-working venues to choose from. Prices vary, depending on location and facilities, but with a dedicated desk costing around £200 per month, it’s worth knowing how to make the most of what these spaces offer.

So how do you choose the right co-working space for you? And how do you get the maximum benefit? Here are four practical tips to consider:

1. Identify your needs

Not all co-working spaces serve the same purpose. Some people are simply looking for a quiet desk outside the home, while others want a social environment where they can meet people, exchange ideas and build connections.

Being clear about what you want, whether it’s productivity, networking opportunities or skill development, is the first step.

Smaller, independently run spaces often place greater emphasis on community building, with managers who organise regular informal events such as “lunch and learn” sessions or workshops. These environments can create more opportunities for social interaction and learning.

By contrast, larger corporate-style spaces may offer more polished facilities and business services, but with fewer opportunities for facilitated interaction. Choosing the right co-working environment means considering the type of space and how you plan to use it.

2. Give it a try

Co-working spaces are often advertised as being open and inclusive. But research I worked on with colleagues shows that experiences can vary depending on factors such as age, gender or professional background.

Some spaces will probably feel more welcoming than others, particularly ones where equality, diversity and inclusion are a deliberate part of their design and ethos.

Many spaces are now also set up with specific groups in mind. For example, some cater to female entrepreneurs, while others offer tailored support for neurodivergent workers.

Before committing, it’s worth visiting a space, attending an event, or trying a short term pass (for a couple of days or a week) to see whether it feels like a good fit.

3. It’s more than a desk

It’s easy to treat co-working spaces as simply a place to work. But research suggests much of its value lies in the connections, community and everyday interactions it makes possible.

Casual conversations in the kitchen or spontaneous exchanges over lunch can help build communication skills, expand professional networks, and spark new collaborations. Evidence suggests that these benefits tend to be particularly strong for those who are newer to a city, earlier in their careers, or working independently. They may have have less established local networks or fewer everyday opportunities for office-based interaction, making them more likely to seek out social connections within co-working spaces.

If you only show up, put your headphones while you work and then leave, you may miss out on some of the main advantages of co-working – the opportunity to connect with others and become part of a community. Making the most of these spaces often means being willing to take that first step, engage with others and gradually find your own circle.

4. Take advantage

If your work involves specialised tools, digital technology or continuous skill development, you may need more than just wifi and coffee from a co-working space.

Many now offer access to specialist software and cutting edge equipment such as 3D printers or virtual reality devices, which can be costly or difficult to access by yourself.

Some go a step further and organise workshops and training sessions, or even events that reflect the latest developments in a particular field. These resources can be particularly valuable for independent workers including freelancers and the self-employed, who may not have access to structured on-the-job training through an employer.

Using them can help you build practical, up-to-date technical and digital skills, especially as new technologies and AI continue to reshape the skills demanded in many industries. So don’t overlook what’s on offer, whether it’s a workshop, a new tool, or a piece of equipment. Making use of these opportunities can help you stay adaptable, keep learning and be better prepared for what comes next.

Overall then, co-working spaces can offer valuable opportunities to learn new skills, build networks and adapt to changing ways of working. But these benefits are not automatic and they are not the same for everyone.

Getting the most out of co-working often depends on how you use the space and whether it matches your needs. At its best, co-working is not just about renting a desk, but about finding an environment where you can connect, learn and grow.

Zihan Wang receives funding from Made Smarter Innovation: Centre for People-Led Digitalisation, at the University of Bath, University of Nottingham and Loughborough University. The project was funded by the Engineering and Physical Sciences Research Council (EPSRC) (grant number EP/V062042/1).

– ref. Thinking of joining a co-working space? Here are four ways to make the most of it – https://theconversation.com/thinking-of-joining-a-co-working-space-here-are-four-ways-to-make-the-most-of-it-281286

Source: The Conversation – UK – By Nima Shokri, Executive Co-Director, Institute for Water, Environment and Health (UNU-INWEH), United Nations University; Technical University of Hamburg

The Strait of Hormuz – the narrow waterway through which between 20% and 25% of the world’s seaborne oil normally passes – has been effectively closed for just over two months.

As tensions have escalated, Iran has restricted passage through the Strait, while the US has imposed a naval blockade on Iranian shipping, sharply limiting Tehran’s ability to export crude. On May 3, the US president Donald Trump announced Project Freedom, by which US warships would escort vessels from countries not involved in the conflict through the Strait. But some reports have suggested that Iran has since fired on several ships attempting to transit and the waterway remains effectively closed.

The immediate consequences are tankers stranded, prices surging, and Iran rapidly running out of places to store its oil. Analysts now warn that storage could fill within weeks, forcing producers to shut wells altogether.

But the deeper story lies far below the surface. Oil wells are not designed to be switched off and on at will. And when they are, the damage can linger long after the crisis has passed.

To understand why, it helps to ditch the idea of oil fields as underground lakes. In reality, oil sits trapped inside microscopic pores in rock, typically a hundredth of a millimeter wide, held there by pressure, temperature, and a delicate balance between oil, gas and water.

Shutting them down, especially abruptly and for long periods, can alter their internal balance in ways that are difficult, sometimes impossible, to reverse. Production works because the system is in motion. When a well is open, pressure differences drive oil toward the wellbore (a drilled channel connecting the oil reservoir to the surface). Over time, that pressure naturally declines, which is why operators use techniques such as water or gas injection to maintain flow.

The key point is that reservoirs are dynamic. They depend on continuous management to remain productive.

Shut the well and the movement of the oil stops. The consequences begin almost immediately. One of the first changes occurs in pressure distribution. While shutting down a well can temporarily allow pressure to build back up near the wellbore, the broader reservoir may experience uneven redistribution.

In fields that rely on carefully managed injection, where water or gas is pumped in to push oil out, halting operations disrupts that system. The injected fluids can migrate unpredictably, sometimes bypassing oil-rich zones entirely when production resumes. The fluid can chose a different path for movement so it may no longer push the oil out of the reservoir.

Then there is the chemistry. Crude oil is not a uniform substance; it contains heavier components such as waxes and asphaltenes — long-chain hydrocarbons and dense, complex molecules that can solidify or precipitate out under changing conditions. Under stable flow conditions, these remain dissolved. But when flow stops and temperatures or pressures change, these components can essentially clog the tiny pores in the rock or the well itself. Once deposited, these materials can restrict flow unless expensive – and not always successful – techniques are used to repair the damage.

Water adds another layer of complexity. All reservoirs contain formation water (the naturally occurring water trapped in the rock alongside oil and gas), and in some cases injected seawater. When a well is shut in, water can intrude into zones that previously produced mostly oil. Over time, this “water invasion” can become entrenched, meaning that when production resumes, the well produces far more water and far less oil. Separating and disposing of that water is costly, and in some cases the oil production becomes uneconomic.

There are also mechanical risks. The well itself is lined with steel casing and cement, and is designed to operate under certain conditions. Long shutdowns can lead to corrosion, scaling (mineral build-up), or even structural integrity issues. In extreme cases, restarting a well can require significant reworking, akin to reopening a mine that has partially collapsed.

Perhaps the most misunderstood aspect is what happens at the scale of the whole oil reservoir over longer periods. Some reservoirs are highly sensitive to pressure changes. If pressure drops too low or fluctuates unpredictably, the rock structure can compact. This compaction reduces the pores available to store and transmit fluids, permanently lowering the field’s production potential.

Gas behaviour also matters. In many reservoirs, gas is dissolved in oil under high pressure. When pressure falls below a certain threshold, gas comes out of solution, which forms bubbles that can block flow pathways . If this happens unevenly during a shutdown, it can leave behind pockets of oil that are effectively stranded.

All of this helps explain why operators are cautious about shutting in production unless they have to. It is not just a matter of lost revenue during downtime – it’s the risk of losing future production capacity altogether. That said, not all wells suffer equally. Some reservoirs are more resilient.

In many cases, particularly in large conventional fields, production can be restored relatively quickly after a shutdown, as seen in past disruptions. But this doesn’t mean the reservoir is unaffected – even when output returns, subtle changes can reduce efficiency, increase costs, or leave some oil permanently unrecovered. In practice, this can mean a reduction in how much oil is ultimately recoverable. Some pockets may become harder to access or uneconomic to produce under normal conditions, even if they remain physically in place. That does not imply the oil is lost forever, but it can shift part of it beyond reach with current technology or prices, effectively lowering the field’s long-term yield.

There are environmental risks too. Closure of wells may cut emissions in the short term, but pressure instability can increase methane leakage. Restarting wells often involves flaring and venting, adding further emissions. Over time, water intrusion and reservoir damage can raise the environmental cost per barrel, as more energy is needed to extract less oil.

Modern engineering can mitigate some risks through careful planning maintaining minimal circulation, managing pressure, or using chemical treatments. But these measures require time, coordination, and resources, which may not be available in a sudden geopolitical crisis.

The broader lesson is that oil production is not easily paused and resumed like a factory assembly line. It is a continuous interaction with a complex natural system. Interruptions especially abrupt, large-scale ones can leave lasting scars beneath the surface, long after the valves are reopened.

Nima Shokri is affiliated with Hamburg University of Technology.

Martin J. Blunt 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. Shutting Iran’s oil wells may be straightforward – but the consequences are not – https://theconversation.com/shutting-irans-oil-wells-may-be-straightforward-but-the-consequences-are-not-281999