(The Conversation) – Tackling climate change by planting trees has an intuitive appeal. They absorb the greenhouse gas carbon dioxide from the atmosphere without using expensive technology.

The suggestion that you can plant trees to offset your carbon emissions is widespread. Many businesses, from those selling shoes to booze, now offer to plant a tree with each purchase, and more than 60 countries have signed up to the Bonn Challenge, which aims to restore degraded and deforested landscapes.

However, expanding tree cover could affect the climate in complex ways. Using models of the Earth’s atmosphere, land and oceans, we have simulated widescale future forestation. Our new study shows that this increases atmospheric carbon dioxide removal, beneficial for tackling climate change. But side-effects, including changes to other greenhouse gases and the reflectivity of the land surface, may partially oppose this.

Our findings suggest that while forestation – the restoration and expansion of forests – can play a role in tackling climate change, its potential may be smaller than previously thought.

When forestation occurs alongside other climate change mitigation strategies, such as reducing emissions of greenhouse gases, the negative side-effects have a smaller impact. So, forestation will be more effective as part of wider efforts to pursue sustainable development. Trees can help fight climate change, but relying on them alone won’t be enough.

What does the future hold?

Future climate projections suggest that to keep warming below the Paris Agreement 2°C target, greenhouse gas emissions must reach net-zero by the mid-to-late 21st century, and become net negative thereafter. As some industries, such as aviation and shipping, will be exceedingly difficult to decarbonise fully, carbon removal will be needed.

Forestation is a widely proposed strategy for carbon removal. If deployed sustainably – by planting mixtures of native trees rather than monocultures, for instance – forestation can provide other benefits including protecting biodiversity, reducing soil erosion, and improving flood protection.

We considered an “extensive forestation” strategy which expands existing forests over the course of the 21st century in line with current proposals, adding trees where they are expected to thrive while avoiding croplands.

In our models, we paired this strategy with two future climate scenarios – a “minimal effort” scenario with average global warming exceeding 4°C, and a “Paris-compatible” scenario with extensive climate mitigation efforts. We could then compare the extensive forestation outcome to simulations with the same climate but where levels of forestation followed more expected trends: the minimal effort scenario sees forest cover drop as agriculture expands, and the Paris-compatible scenario features modest increases in global forest cover.

Image by Anja from Pixabay

Up in the air

The Earth’s energy balance depends on the energy coming in from the Sun and the energy escaping back out to space. Increasing forest cover changes the Earth’s overall energy balance. Generally, changes that decrease outgoing radiation cause warming. The greenhouse effect works this way, as outgoing radiation is trapped by gases in the atmosphere.

Forestation’s ability to lower atmospheric CO₂, and therefore increase the radiation escaping to space, has been well studied. However, the amount of carbon that could feasibly be removed remains a subject of debate.

Forestation generally reduces land surface reflectivity (albedo) as darker trees replace lighter grassland. Decreases in albedo levels oppose the beneficial reduction of atmospheric CO₂, as less radiation escapes back to space. This is particularly important at higher latitudes, where trees cover land that would otherwise be covered with snow. Our scenario features forest expansion primarily in temperate and tropical regions.

Forests emit large quantities of volatile organic compounds (VOCs), with these emissions increasing with rising temperatures. VOCs react chemically in the atmosphere, affecting the concentrations of methane and ozone, which are also greenhouse gases. We find the enhanced VOC emissions from greater forest cover and temperatures increase levels of methane and, typically, ozone. This reduces the amount of radiation escaping to space, further opposing the removal of carbon.

However, the reaction products of VOCs can contribute to aerosols, which reflect incoming solar radiation and help form clouds. Increases in these aerosols with rising VOC emissions from greater forest cover result in more radiation escaping to space.

We find the net effect of changes to albedo, ozone, methane and aerosol is to reduce the amount of radiation escaping to space, cancelling out part of the benefit of reducing atmospheric CO₂. In a future where climate mitigation is not a priority, up to 30% of the benefit is cancelled out, while in a Paris-compatible future, this drops to 15%.

Cooler solutions

Tackling climate change requires efforts from all sectors. While forestation will play a role, our work shows that its benefits may not be as great as previously thought. However, these negative side-effects aren’t as impactful if we pursue other strategies, especially reducing our greenhouse gas emissions, alongside forestation.

This study hasn’t considered local temperature changes from forestation as a result of evaporative cooling, or the impact of changes to atmospheric composition caused by changes in the frequencies and severities of wildfires. Further work in these areas will complement our research.

Nevertheless, our study suggests that forestation alone is unlikely to fix our warming planet. We need to rapidly reduce our emissions while enhancing the ability of the natural world to store carbon. It is important to stress-test climate mitigation strategies in detail, because so many complex systems are at play.

James Weber, Lecturer in Atmospheric Radiation, Composition and Climate, University of Reading and James A. King, Research Associate in Climate Change Mitigation, University of Sheffield

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

The Nile is one of the world’s most famous rivers. It’s also Africa’s most important freshwater system. About 300 million people live in the 11 countries it flows through. Many rely on its waters for agriculture and fishing to make a living.

The Nile’s two main tributaries, the Blue Nile and the White Nile, come together in Sudan’s capital city, Khartoum. This industrial hub has grown rapidly over the past few decades.

The Nile is not immune to the same pollutants that affect rivers all over the world. Plastic debris is of particular concern. Over time plastics break down into smaller pieces known as microplastics. These are tiny plastic particles with a maximum size of five millimetres, all the way down to the nanoscale. Recent research found that

rivers are modelled to export up to 25,000 tons of plastics from their sub-basins to seas annually. Over 80% of this amount is microplastic.

This has huge negative consequences for biodiversity and the climate. As microplastics degrade, scientists have found, they produce greenhouse gases. Airborne microplastics may influence the climate by scattering and absorbing solar and terrestrial radiation, leading to atmospheric warming or cooling depending on particle size, shape and composition. It also negatively affects animal and human health. Microplastics have been shown in laboratory studies to be toxic to animals and cells.

Much of the research about microplastics in African waters has focused on marine and coastal areas. To address this gap, I conducted a study to assess the presence of microplastics in the River Nile in Khartoum. My students and I tested for the presence of microplastics in Nile tilapia. This popular African freshwater fish species forms the basis of commercial fisheries in many African countries, including Sudan.

Photo by Islam Hassan on Unsplash

The results do not make for happy reading. In the 30 freshly caught fish we surveyed, we found a total of 567 microplastic particles. This shows that the River Nile is contaminated with microplastics that can be consumed or absorbed in various ways by the tilapia and other aquatic organisms.

Our sample

The fish used in our study were caught just after the meeting point of the two Niles, known in Arabic as Al-Mogran.

We visited the Al-Mawrada fish market in the Omdurman area, which is also alongside the Nile. All 30 specimens we bought were freshly caught.

We dissected the fish to remove their digestive tracts. The individual tracts were treated so they would digest any organic matter they contained without interfering with the analysis of microplastics. The resulting solution was subject to another extraction procedure and we then conducted physical and chemical analyses.

Every specimen had microplastics in its digestive tract.

The number ranged from as few as five to as many as 47 particles per single fish. In total we identified 567 particles. This is high compared to studies that have reported microplastics in tilapia species in other rivers and lakes. There is, as yet, no global guideline or standard for what might be an “acceptable” number.

Shape, size and colour

We detected different sizes of microplastics (0.04mm to 4.94mm), shapes (fibres, fragments, films, foams and pellets) and colours. The most common were very small (less than 1mm), fibrous – they appear slender and elongated – and coloured (dyed).

These characteristics make sense because of how fish and other aquatic organisms feed. Nile tilapia are versatile feeders: they consume a variety of organisms including phytoplankton, aquatic plants, invertebrates, detritus, bacterial films, as well as other fish and fish eggs. That puts them at a high risk of ingesting microplastics.

Nile tilapia are also more likely to consume particles that are within a similar size range as their natural prey, as well as the same shape and colour.

Smaller microplastics are especially good carriers for other pollutants such as heavy metals, resulting in additional health risks. Their small size also makes it easier for them to move into organs like the liver. Studies have found microplastics in the tissues, muscles, livers, blubber and lungs of other aquatic as well as marine mammal species.

Fibres, the most dominant shape found in our specimens, stay in the intestine for longer than other microplastic shapes. This, too, can lead to health problems for the fish. Coloured microplastics contain dyes, many of which contain toxic chemicals.

This all has serious implications for human health, as people catch and eat the fish, which introduces those microplastics and associated chemicals into their bloodstreams.

Pollution sources

Where does all this plastic originate? For starters, 65% of plastic waste in Khartoum is disposed of in open dumps. From there, it contaminates water bodies and other parts of the environment.

Image by Refaat Naiem from Pixabay

The city’s wastewater treatment system is ineffective. The three wastewater treatment plants in Khartoum state, Karary, Wd-Daffiaa and Soba, are outdated and do not meet local and international standards. That means untreated effluent from domestic, industrial and agricultural activities is another probable source of microplastic pollution.

There are also countless recreational sites along the River Nile in Khartoum. The Nile Street is the most popular in the capital city, hosting water sports, restaurants, cafes, clubs, event venues and hotels, as well as the tea ladies (women who serve hot beverages from makeshift mobile cafes along the banks of the river). However, waste disposal and collection practices are sorely lacking, so plastic litter from these leisure activities leaks into the river.

No easy fix

Tackling microplastic pollution is not easy. It will require technological advances, as well as the collective efforts of consumers, producers, governments and the scientific community.

As consumers, we need to change our behaviour around plastic products, especially single-use plastics. For example, opt for fabric shopping bags instead of plastic bags; use glass and metal containers. Recycling is also important.

Governments must enforce waste management regulations and improve waste management practices, as well as helping to improve public awareness. Strategies and policies must explicitly feature microplastics.

Scientists can not only fill the knowledge gaps around microplastics. Communicating scientific findings is crucial; so too is developing innovations to protect against microplastics and their harmful effects.

I would like to thank and acknowledge my student Hadeel Alamin, who conducted this study with me.

Dalia Saad, Researcher, School of Chemistry, University of the Witwatersrand, University of the Witwatersrand

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

Imagine you share an Instagram post about an upcoming protest, but none of your hundreds of followers like it. Are none of your friends interested in it? Or have you been shadow banned?

Social media can be useful for political activists hoping to share information, calls to action and messages of solidarity. But throughout Israel’s war on Gaza, social media users have suspected they are being censored through “shadow banning” for sharing content about Palestine.

Shadow banning describes loss of visibility, low engagement and poor account growth on platforms like Instagram, TikTok and X (formerly Twitter). Users who believe they are shadow banned suspect platforms may be demoting or not recommending their content and profiles to the main discovery feeds. People are not notified of shadow banning: all they see is the poor engagement they are getting.

Human Rights Watch, an international human rights advocacy non-governmental organisation, has recently documented what it calls “systemic censorship” of Palestine content on Facebook and Instagram. After several accusations of shadow banning, Meta (Facebook and Instagram’s parent company) argued the issue was due to a “bug” and “had nothing to do with the subject matter of the content”.

I have been observing shadow bans both as a researcher and social media user since 2019. In addition to my work as an academic, I am a pole dancer and pole dance instructor. Instagram directly apologised to me and other pole dancers in 2019, saying they blocked a number of the hashtags we use “in error”. Based on my own experience, I conducted and published one of the very first academic studies on this practice.

Why platforms shadow ban

Content moderation is usually automated – carried out by algorithms and artificial intelligence. These systems may also, inadvertently or by design, pick up “borderline” controversial content when moderating at scale.

Photo by Ian Hutchinson on Unsplash

Most platforms are based in the US and govern even global content according to US law and values. Shadow banning is a case in point, typically targeting sex work, nudity and sexual expression prohibited by platforms’ community guidelines.

Moderation of nudity and sexuality has become more stringent since 2018, after the introduction of two US laws, the Fight Online Sex Trafficking Act (Fosta) and Stop Enabling Sex Trafficking Act (Sesta), that aimed to crack down on online sex trafficking.

The laws followed campaigns by anti-pornography coalitions and made online platforms legally liable for enabling sex trafficking (a crime) and sex work (a job). Fearing legal action, platforms began over-censoring any content featuring nudity and sexuality around the world, including of legal sex work, to avoid breaching Fosta-Sesta.

Although censorship of nudity and sex work is heralded as a means to protect children and victims of non-consensual image sharing, it can have serious consequences for the livelihoods and wellbeing of sex workers and adult content creators, as well as for freedom of expression.

Platforms’ responses to these laws should have been a warning about what was to come for political speech.

Social media users reported conversations and information about Black Lives Matter protests were shadowbanned in 2020. Now journalistic, activist and fact-checking content about Palestine also appears to be affected by this censorship technique.

Platforms are unlikely to admit to a shadow ban or bias in their content moderation. But their stringent moderation of terrorism and violent content may be leading to posts about Palestine that is neither incitement to violence nor terror-related getting caught in censorship’s net.

How I proved I was shadow banned

For most social media users, shadow banning is difficult to prove. But as a researcher and a former social media manager, I was able to show it was happening to me.

As my passion for pole dancing (and posts about it) grew, I kept a record of my reach and follower numbers over several years. While my skills were improving and my follower count was growing, I noticed my posts were receiving fewer views. This decline came shortly after Fosta-Sesta was approved.

It wasn’t just me. Other pole dancers noticed that content from our favourite dancers was no longer appearing in our Instagram discovery feeds. Shadowbanning appeared to also apply to swathes of pole-dancing-related hashtags.

I was also able to show that when content surrounding one hashtag is censored, algorithms restrict similar content and words. This is one reason why some creators use “algospeak” editing content to trick the algorithm into not picking up words it would normally censor, as seen in anti-vaccine content throughout the pandemic.

Check if you are being shadow banned

TikTok and Twitter do not notify users that their account is shadow banned, but, as of 2022, Instagram does. By checking your “account status” in the app’s settings, you can see if your content has been marked as “non-recommendable” due to potential violations of Instagram’s content rules. This is also noticeable if other users have to type your full profile name for you to appear in search. In short, you are harder to find. In August 2023, X owner Elon Musk said that the company was working on a way for users to see if they had been affected by shadow bans, but no such function has been introduced. (The Conversation has contacted X for comment.)

The ability to see and appeal a shadow ban are positive changes, but mainly a cosmetic tweak to a freedom of expression problem that mostly targets marginalised groups. While Instagram may now be disclosing their decisions, the effect is the same: users posting about nudity, LGBTQ+ expression, protests and Palestine are often the ones to claim they are shadow banned.

Social media platforms are not just for fun, they’re a source of work and political organising, and a way to spread important information to a large audience. When these companies censor content, it can affect the mental health and the livelihoods of people who use it.

These latest instances of shadow banning show that platforms can pick a side in active crises, and may affect public opinion by hiding or showing certain content. This power over what is visible and what is not should concern us all.

Carolina Are, Innovation Fellow, Northumbria University, Newcastle

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

A heat wave in Greenland and a storm in Antarctica. These kinds of individual weather “events” are increasingly being supercharged by a warming climate. But despite being short-term events they can also have a much longer-term effect on the world’s largest ice sheets, and may even lead to tipping points being crossed in the polar regions.

We have just published research looking at these sudden changes in the ice sheets and how they may impact what we know about sea level rise. One reason this is so important is that the global sea level is predicted to rise by anywhere between 28 cm and 100cm by the year 2100, according to the IPCC. This is a huge range – 70 cm extra sea-level rise would affect many millions more people.

Partly this uncertainty is because we simply don’t know whether we’ll curb our emissions or continue with business as usual. But while possible social and economic changes are at least factored in to the above numbers, the IPCC acknowledges its estimate does not take into account deeply uncertain ice-sheet processes.

Sudden accelerations

The sea is rising for two main reasons. First, the water itself is very slightly expanding as it warms, with this process responsible for about a third of the total expected sea-level rise.

Second, the world’s largest ice sheets in Antarctica and Greenland are melting or sliding into the sea. As the ice sheets and glaciers respond relatively slowly, the sea will also continue to rise for centuries.

Photo by Cassie Matias on Unsplash

Scientists have long known that there is a potential for sudden accelerations in the rate at which ice is lost from Greenland and Antarctica which could cause considerably more sea-level rise: perhaps a metre or more in a century. Once started, this would be impossible to stop.

Although there is a lot of uncertainty over how likely this is, there is some evidence that it happened about 130,000 years ago, the last time global temperatures were anything close to the present day. We cannot discount the risk.

To improve predictions of rises in sea level we therefore need a clearer understanding of the Antarctic and Greenland ice sheets. In particular, we need to review if there are weather or climate changes that we can already identify that might lead to abrupt increases in the speed of mass loss.

Weather can have long-term effects

Our new study, involving an international team of 29 ice-sheet experts and published in the journal Nature Reviews Earth & Environment, reviews evidence gained from observational data, geological records, and computer model simulations.

We found several examples from the past few decades where weather “events” – a single storm, a heatwave – have led to important long-term changes.

The ice sheets are built from millennia of snowfall that gradually compresses and starts to flow towards the ocean. The ice sheets, like any glacier, respond to changes in the atmosphere and the ocean when the ice is in contact with sea water.

These changes could take place over a matter of hours or days or they may be long-term changes from months to years or thousands of years. And processes may interact with each other on different timescales, so that a glacier may gradually thin and weaken but remain stable until an abrupt short-term event pushes it over the edge and it rapidly collapses.

Because of these different timescales, we need to coordinate collecting and using more diverse types of data and knowledge.

Historically, we thought of ice sheets as slow-moving and delayed in their response to climate change. In contrast, our research found that these huge glacial ice masses respond in far quicker and more unexpected ways as the climate warms, similarly to the frequency and intensity of hurricanes and heatwaves responding to changes with the climate.

Ground and satellite observations show that sudden heatwaves and large storms can have long-lasting effects on ice sheets. For example a heatwave in July 2023 meant at one point 67% of the Greenland ice sheet surface was melting, compared with around 20% for average July conditions. In 2022 unusually warm rain fell on the Conger ice shelf in Antarctica, causing it to disappear almost overnight.

These weather-driven events have long “tails”. Ice sheets don’t follow a simple uniform response to climate warming when they melt or slide into the sea. Instead their changes are punctuated by short-term extremes.

For example, brief periods of melting in Greenland can melt far more ice and snow than is replaced the following winter. Or the catastrophic break-up of ice shelves along the Antarctic coast can rapidly unplug much larger amounts of ice from further inland.

Failing to adequately account for this short-term variability might mean we underestimate how much ice will be lost in future.

What happens next

Scientists must prioritise research on ice-sheet variability. This means better ice-sheet and ocean monitoring systems that can capture the effects of short but extreme weather events.

This will come from new satellites as well as field data. We’ll also need better computer models of how ice sheets will respond to climate change. Fortunately there are already some promising global collaborative initiatives.

We don’t know exactly how much the global sea level is going to rise some decades in advance, but understanding more about the ice sheets will help to refine our predictions.

Edward Hanna, Professor of Climate Science and Meteorology, University of Lincoln and Ruth Mottram, Climate Scientist, National Centre for Climate Research, Danish Meteorological Institute

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

Buildings are often celebrated as symbols of history, political events and creative expression. However, the simplest, most pure function of buildings is often forgotten: the way they fulfil needs and form memories.

For years, research has shown that buildings, people’s memories and everyday life are connected elements that form our attachment to a place and create our relationships to our “homeˮ. This triangle of connection helps us identify with places and feel like we belong somewhere.

Gaza has long been cherished as a sanctuary for creative experimentation, and as a place where resilient people strive to defy the violence of colonisation. Within this landscape of destruction and occupation, the locals have always tried to hold onto the concept of home, beyond a fleeting shelter that could vanish with the next bombing campaign.

However, this continuous cycle of destruction and hopeful reconstruction has now come to an abrupt halt. Since October 7 2023, the bombardment of Gaza is reported to have damaged more than 100 historic sites and destroyed 69,700 homes.

Middle East Eye Video: “Footage from Unrwa shows the vast scale of destruction in Gaza ”

At the time of writing, 1.9 million Palestinians have been displaced. This ongoing urbicide – the destruction of cultural hubs in the built environment – also threatens that triangle connecting people to their homes, land and heritage.

With more than half of Gazaʼs buildings either damaged or destroyed, it is impossible to cover the immense changes to the lives of these Palestinians in one article. So, here are just three examples of these lost buildings, and how their destruction has affected the everyday lives of local people in Gaza.

The Great Omari Mosque

A reflection of Palestine’s history where multiple religions coexisted, the Great Omari Mosque has undergone multiple transformations throughout history.

Built on the site of a pagan temple, this fifth-century church became a mosque in AD635. With a courtyard area of 1,190m², the mosque was the second-largest in Palestine and served as a daily destination for more than 3,000 worshippers.

Situated near Palestine Square, it has played a crucial role in the everyday life of Gaza, as mosques in Middle Eastern cities foster social interactions, informal conversations and societal bonds. But this incubation of societal interactions came to an abrupt stop in December 2023, when the mosque was reduced to rubble.

Embed from Getty Images
This picture taken on January 5, 2024, shows Gaza City’s Omari Mosque, the oldest mosque in Gaza, damaged in Israeli bombardment during the ongoing battles between Israel and the Palestinian Hamas movement. The conflict triggered by Hamas’s deadly October 7 attack on Israel has caused massive destruction in the Gaza Strip, killing tens of thousands and leaving residents on the brink of famine. Much of the territory has become unrecognisable, as entire neighbourhoods which were once bustling with people, cars and donkey-drawn carts have been reduced to rubble. (Photo by AFP) (Photo by -/AFP via Getty Images)

Palestine Square

Palestine Square has long been the centre of everyday life in Gaza and is widely regarded as the heart of the city. It is significant due to its proximity to the Great Omari Mosque and many services, as well as the passage it provides to various markets.

Urban squares play a crucial role not only in facilitating transportation and passage but also as places that are connected to our identity, memories and how we perceive our city.

Therefore, targeting Palestine Square and completely destroying the surrounding buildings in January posed a threat to some fundamental aspects of people’s daily lives and their sense of belonging to the city.

Omar Al-Mukhtar Street

Often called the most important street in Gaza City, Omar Al-Mukhtar Street is one of its two main thoroughfares along with Al-Wihdi Street.

It serves as the city’s commercial centre and is home to the city hall and public library. However, on October 8 2023, the street became one of the first targets of Israeli airstrikes, abruptly ending the bustling commercial activities that so many people relied on.

This street was not only a place for Palestinian families to fulfil their everyday needs, but a hub for leisure and entertainment. For years, cultural sites like Omar Al-Mukhtar Street have fostered social bonds, preserved memories, and created societal bonds through everyday life and cultural events.

Seeing past the ashes

Gaza faces a challenging and lengthy path to recovery. These destroyed buildings serve as a reminder of the lost everyday life and rich cultural heritage hidden beneath the rubble.

The scale of destruction is immense, as is the humanitarian loss and disruption to daily life patterns. All will have long-lasting effects on the city’s identity and the local community’s heritage.

While it is important to highlight the destruction of buildings, it is even more crucial to shed light on how this affects everyday life and the functioning of the city. Gaza, once a hub of creative experimentation, now lies in ruins and urgently requires humanitarian, architectural and heritage support.

In this complex landscape, aid efforts should prioritise the restoration of physical structures that facilitate everyday life. Commercial spaces, urban squares, places of worship and homes formed a network that sustained daily life in Palestine.

When the bombing finally ends, it will be crucial to uncover and restore this network to restore Palestinians’ sense of belonging to their cities – and connection with their land.

Yousif Al-Daffaie, Lecturer and Researcher, School of Architecture, Design, and the Built Environment, Nottingham Trent University

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

Amid the escalating threats of a warming world, and with the latest annual United Nations global climate conference (COP28) behind us, there is one critical message that’s often left out of the climate change discourse. Halting overfishing is itself effective climate action.

This argument is the logical conclusion of a plethora of studies that unequivocally assert that stopping overfishing isn’t just a necessity, it’s a win-win for ocean vitality, climate robustness and the livelihoods reliant on sustainable fisheries.

The intricate relationship between climate change and ocean ecosystems was the subject of recent collaborative research — led by researchers at the University of British Columbia — that highlighted the crucial links between overfishing and climate change.

Finding the connections

Our collaborative team of international researchers applied a host of methodologies ranging from literature reviews to quantitative and quality analysis. The findings of this research illuminate eight key multifaceted impacts.

1 — Ending overfishing isn’t merely an ecological imperative but a vital climate action. Doing so would bolster marine life resilience in the face of climate shifts and reduce associate carbon emissions.

2 — Large subsidized fishing boat fleets can actually be a burden on small-scale fisheries, leaving them disproportionately vulnerable to shocks. In turn, overfishing not only depletes resources but also escalates carbon emissions, intensifying climate impacts on these fisheries and their communities, particularly women.

Additionally, the vulnerability of shellfish fisheries to climate stressors further underscores the importance of adaptive strategies tailored to local conditions.

3 — Success stories, like the recovery of European hake stocks, reveal a direct tie between stock recuperation and reduced emissions intensity from fisheries. We must champion and also learn from these successes.

4 — Ecosystem-based fisheries management reverses the “order of priorities so that management starts with ecosystem considerations rather than the maximum exploitation of several target species.”

Ecosystem-based fisheries management has considerable potential to enhance sustainable catches while fostering carbon sequestration. This is perhaps best exemplified by the successful implimentation of ecosystem-based fisheries management in the western Baltic Sea.

5 — Heavy metal pollution in the ocean — such as mercury or lead waste — intensifies the negative impacts of warming and overfishing. This pollution reinforces the need for developing multifaceted regulations based around ecosystem and ocean sustainability solutions.

6 — Overfishing exacerbates climate and biodiversity threats. Climate change contributes to less defined and predictable seasons and is causing reproductive challenges and the propagation of diseases in fish populations — among other issues.

Via Pixabay. .

Adding to these problems, overfishing itself is altering ecological dynamics, modifying habitats and opening new pathways for invasive species. These compounding crises further exacerbate the impacts of overfishing on marine ecosystems while at the same time making fish populations more vulnerable to climate change.

The above factors all combine to reduce the catch potential in any given ecosystem. In turn, fishers are forced to venture farther and deeper in the ocean to fish — increasing carbon emissions, personal risk factors to fishers and bycatch concerns.

7 — International fisheries management must play a central role in promoting biodiversity and retaining the ocean’s carbon sequestration potential. While 87 nations have signed the UN’s Biodiversity of Areas Beyond National Jurisdiction Treaty (also known as the High Seas Treaty), only one has ratified it. This treaty must be fully ratified and its effective implementation should be contingent upon the creation of marine protected areas that cover at least 30 per cent of the high seas.

8 — The ocean has huge carbon sequestration potential. Shifting from the generally accepted maximum of sustainable yield management to maximizing carbon sequestration in fisheries management could further advance climate goals.

Future regulations should allocate a percentage of the annual fish quota to maintain the carbon sequestration function of marine animals. Simply put, beyond just being food, fish stocks serve vital carbon sequestration and biodiversity services that directly benefit humanity. Future regulations should reflect this reality.

A simple goal

This joint collaborative research underscores the urgency of this issue. Ending overfishing isn’t just an ecological imperative but a linchpin for climate action. Furthermore, fisheries aren’t mere victims in these dynamics, but have real agency to play a pivotal role in either exacerbating or mitigating climate change.

An ideal governance framework would focus on managing ecosystems with considerations for their diverse benefits, based on the best evidence available. Regulation of fisheries, while controversial, is essential to not overly exploit such a valuable public resource.

As we gear up to the next COP, we would do well to remember these conclusions. Without nurturing ocean life, addressing climate change becomes an uphill battle. Sustainable fisheries management is not just an ecological necessity. It is also the cornerstone of a resilient, sustainable future.

Rashid Sumaila, Director & Professor, Fisheries Economics Research Unit, University of British Columbia

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

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.

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.

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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.

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.

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.

The stories of hunger emerging from war-ravaged Gaza are stark: People resorting to grinding barely edible cattle feed to make flour; desperate residents eating grass; reports of cats being hunted for food.

The numbers involved are just as despairing. The world’s major authority on food insecurity, the IPC Famine Review Committee, estimates that 90% of Gazans – some 2.08 million people – are facing acute food insecurity. Indeed, of the people facing imminent starvation in the world today, an estimated 95% are in Gaza.

As an expert in Palestinian public health, I fear the situation may not have hit its nadir. In January 2024, many of the top funders to UNRWA, the U.N.’s refugee agency that provides the bulk of services to Palestinians in Gaza, suspended donations to the agency in response to allegations that a dozen of the agency’s 30,000 employees were possibly involved in the Oct. 7, 2023, attack by Hamas. The agency has indicated that it will no longer be able to offer services starting in March and will lose its ability to distribute food and other vital supplies during that month.

With at least 28,000 people confirmed dead and an additional 68,000 injured, Israeli bombs have already had a catastrophic human cost in Gaza – starvation could be the next tragedy to befall the territory.

Indeed, two weeks after Israel initiated a massive military campaign in the Gaza Strip, Oxfam International reported that only around 2% of the usual amount of food was being delivered to residents in the territory. At the time, Sally Abi Khalil, Oxfam’s Middle East director, commented that “there can be no justification for using starvation as a weapon of war.” But four months later, the siege continues to restrict the distribution of adequate aid.

Putting Palestinians ‘on a diet’

Israeli bombs have destroyed homes, bakeries, food production factories and grocery stores, making it harder for people in Gaza to offset the impact of the reduced imports of food.

But food insecurity in Gaza and the mechanisms that enable it did not start with Israel’s response to the Oct. 7 attack.

A U.N. report from 2022 found that a year before the latest war, 65% of Gazans were food insecure, defined as lacking regular access to enough safe and nutritious food.

Multiple factors contributed to this food insecurity, not least the blockade of Gaza imposed by Israel and enabled by Egypt since 2007. All items entering the Gaza Strip, including food, become subject to Israeli inspection, delay or denial.

Basic foodstuff was allowed, but because of delays at the border, it can spoil before it enters Gaza.

A 2009 investigation by Israeli newspaper Ha’aretz found that foods as varied as cherries, kiwi, almonds, pomegranates and chocolate were prohibited entirely.

At certain points, the blockade, which Israel claims is an unavoidable security measure, has been loosened to allow import of more foods; for example, in 2010 Israel started to permit potato chips, fruit juices, Coca-Cola and cookies.

By placing restrictions on food imports, Israel seems to be trying to put pressure on Hamas by making life difficult for the people in Gaza. In the words of one Israeli government adviser in 2006, “The idea is to put the Palestinians on a diet, but not to make them die of hunger.”

To enable this, the Israeli government commissioned a 2008 study to work out exactly how many calories Palestinians would need to avoid malnutrition. The report was released to the public only following a 2012 legal battle.

The blockade also increased food insecurity by preventing meaningful development of an economy in Gaza.

The U.N. cites the “excessive production and transaction costs and barriers to trade with the rest of the world” imposed by Israel as the primary cause of severe underdevelopment in the occupied territories, including Gaza. As a result, in late 2022 the unemployment rate in Gaza stood at around 50%. This, coupled with a steady increase in the cost of food, makes affording food difficult for many Gazan households, rendering them dependent on aid, which fluctuates frequently.

Hampering self-sufficency

More generally, the blockade and the multiple rounds of destruction of parts of the Gaza Strip have made food sovereignty in the territory nearly impossible.

Much of Gaza’s farmland is along the so-called “no-go zones,” which Israel had rendered inaccessible to Palestinians, who risk being shot if they attempt to access these areas.

Gaza’s fishermen are regularly shot at by Israeli gunboats if they venture farther in the Mediterranean Sea than Israel permits. Because the fish closer to the shore are smaller and less plentiful, the average income of a fisherman in Gaza has more than halved since 2017.

Meanwhile, much of the infrastructure needed for adequate food production – greenhouses, arable lands, orchards, livestock and food production facilities – have been destroyed or heavily damaged in various rounds of bombing in Gaza. And international donors have hesitated to hastily rebuild facilities when they cannot guarantee their investment will last more than a few years before being bombed again.

The latest siege has only further crippled the ability of Gaza to be food self-sufficient. By early December 2023, an estimated 22% of agricultural land had been destroyed, along with factories, farms, and water and sanitation facilities. And the full scale of the destruction may not be clear for months or years.

Meanwhile, Israel’s flooding of the tunnels under parts of the Gaza Strip with seawater risks killing remaining crops, leaving the land too salty and rendering it unstable and prone to sinkholes.

Starvation as weapon of war

Aside from the many health effects of starvation and malnutrition, especially on children, such conditions make people more vulnerable to disease – already a significant concern for those living in the overcrowded shelters where people have been forced to flee.

In response to the current hunger crisis in Gaza, Alex de Waal, author of “Mass Starvation: The History and Future of Famine,” has made clear: “While it may be possible to bomb a hospital by accident, it is not possible to create a famine by accident.” He argues that the war crime of starvation does not need to include outright famine – merely the act of depriving people of food, medicine and clean water is sufficient.

The use of starvation is strictly forbidden under the Geneva Conventions, a set of statutes that govern the laws of warfare. Starvation has been condemned by United Nations Resolution 2417, which decried the use of deprivation of food and basic needs of the civilian population and compelled parties in conflict to ensure full humanitarian access.

Human Rights Watch has already accused Israel of using starvation as a weapon of war, and as such it accuses the Israeli government of a war crime. The Israeli government in turn continues to blame Hamas for any loss of life in Gaza.

Yet untangling what Israel’s intentions may be – whether it is using starvation as a weapon of war, to force mass displacement, or if, as it claims, it is simply a byproduct of war – does little for the people on the ground in Gaza.

They require immediate intervention to stave off catastrophic outcomes. As one father in Gaza reported, “We are forced to eat one meal a day – the canned goods that we get from aid organizations. No one can afford to buy anything for his family. I see children here crying from hunger, including my own children.”

Yara M. Asi, Assistant Professor of Global Health Management and Informatics, University of Central Florida

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

The Armenian quarter in Jerusalem’s Old City is facing its biggest crisis in a long time. A Jewish businessman with connections to the radical settler movement is poised to develop a quarter of the neighbourhood’s territory, with plans to build a luxury hotel. If this goes ahead, it will significantly change part of Jerusalem’s Old City and hasten the demographic shift towards the city’s Jewish population which has been happening for some years.

The Armenian quarter actually makes up one-sixth of the Old City (the other quarters being the Muslim, the Christian, and the Jewish) and the Armenian presence in Jerusalem dates back to the 4th century. Together with the neighbouring Christian quarter, it is a stronghold for the city’s small Christian minority. The threat of a takeover of parts of the quarter by Jewish settlers is widely seen as altering the demographic status quo to favour Israel’s interests.

Jerusalem: Armenian Christians fight controversial land deal | BBC News Video

In 2021, the Armenian patriarch of Jerusalem, Nourhan Manougian, agreed a 98-year lease over part of the Armenian quarter with the developers. The agreement covers a significant area that today includes a parking lot, buildings belonging to the office of the Armenian church leader – known as the patriarchate – and the homes of five Armenian families.

News of the deal prompted strong protests among the neighbourhood’s Armenians last year. Such was the depth of feeling that in October, the patriarch and the other church leaders felt compelled to cancel the agreement. This led to violent confrontations between settlers and local Armenians.

After a few quiet weeks, fighting broke out again at the end of December when more than 30 men armed with stones and clubs reportedly attacked the Armenians who had been guarding the area for several weeks.

The dispute has now gone to court. The question is whether the lease agreement is valid or whether the unilateral termination makes the agreement void. The patriarchate has engaged lawyers – local and from Armenia and the US – who will present its case that the agreement was not entered into properly because of irregularities in the contract.

Changing East Jerusalem’s demography

This is not a single incident. Since the 1967 six-day War, when the whole of Jerusalem came under Israeli control, there has been a concerted effort to change the demography in the traditionally Arab East Jerusalem.

In many places the authorities are evicting the Arab families who have lived there for decades with the explanation that they lack documents that they own the house. Then a Jewish family moves in.

This change of the demography of East Jerusalem happens through evictions, demolitions and buildings restrictions. This is also happening in Jerusalem’s iconic and touristic Old City.

Almost 20 years ago, there was a minor scandal when it emerged that the Greek Orthodox patriarchate, a large property owner, had entered into a long lease agreement with a Jewish settler organisation regarding two historic hotels.

Now we have a similar incident concerning the Armenian patriarchate. Selling or renting out property to Jewish settlers for a long time is viewed extremely negatively by the Palestinians, who have long fought against illegal Jewish settlements in Palestinian areas.

East Jerusalem is of vital importance to the Palestinians. In proposed plans for a two-state solution, it is the intended capital of a future Palestinian state. Decisively changing the demography there is therefore a priority goal for some in Israel – including the prime minister, Benjamin Netanyahu, who doesn’t want a two-state solution.

Hierarchical institutions

This conflict also underlines an old problem with the Jerusalem’s Christian churches – namely the gap between the leadership and the people. Old churches are by nature hierarchical and the leaders at the top rule supremely. In Jerusalem there is an additional problem in that the church leaders are not always drawn from the local population.

The largest Christian denomination in the Holy Land is the Greek Orthodox Church. Its members are largely Arabs, but the patriarch and the other leading prelates are Greeks.

Nourhan Manougian, the current and 97th Armenian patriarch of Jerusalem, was born in Syria to an Armenian family. The Armenian patriarchate has been accused of corruption and illegitimate sale of property in the past, long before the current crisis.

If the Armenians lose this battle and the settler movement is able to gain control of such a key site, it will harm a vulnerable small minority. And the settler campaign to colonise East Jerusalem under Jewish control will have achieved yet another victory.

Svante Lundgren, Researcher, Lund University

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