Anyone with even a passing interest in the global environment knows all is not well. But just how bad is the situation? Our new paper shows the outlook for life on Earth is more dire than is generally understood.
The research published today reviews more than 150 studies to produce a stark summary of the state of the natural world. We outline the likely future trends in biodiversity decline, mass extinction, climate disruption and planetary toxification. We clarify the gravity of the human predicament and provide a timely snapshot of the crises that must be addressed now.
The problems, all tied to human consumption and population growth, will almost certainly worsen over coming decades. The damage will be felt for centuries and threatens the survival of all species, including our own.
Our paper was authored by 17 leading scientists, including those from Flinders University, Stanford University and the University of California, Los Angeles. Our message might not be popular, and indeed is frightening. But scientists must be candid and accurate if humanity is to understand the enormity of the challenges we face.
Getting to grips with the problem
First, we reviewed the extent to which experts grasp the scale of the threats to the biosphere and its lifeforms, including humanity. Alarmingly, the research shows future environmental conditions will be far more dangerous than experts currently believe.
This is largely because academics tend to specialise in one discipline, which means they’re in many cases unfamiliar with the complex system in which planetary-scale problems — and their potential solutions — exist.
More broadly, the human optimism bias – thinking bad things are more likely to befall others than yourself – means many people underestimate the environmental crisis.
Numbers don’t lie
Our research also reviewed the current state of the global environment. While the problems are too numerous to cover in full here, they include:
a halving of vegetation biomass since the agricultural revolution around 11,000 years ago. Overall, humans have altered almost two-thirds of Earth’s land surface
About 1,300 documentedspecies extinctions over the past 500 years, with many more unrecorded. More broadly, population sizes of animal species have declined by more than two-thirds over the last 50 years, suggesting more extinctions are imminent
about one million plant and animal species globally threatened with extinction. The combined mass of wild mammals today is less than one-quarter the mass before humans started colonising the planet. Insects are also disappearing rapidly in many regions
85% of the global wetland area lost in 300 years, and more than 65% of the oceans compromised to some extent by humans
a halving of live coral cover on reefs in less than 200 years and a decrease in seagrass extent by 10% per decade over the last century. About 40% of kelp forests have declined in abundance, and the number of large predatory fishes is fewer than 30% of that a century ago.
A bad situation only getting worse
The human population has reached 7.8 billion – double what it was in 1970 – and is set to reach about 10 billion by 2050. More people equals more food insecurity, soil degradation, plastic pollution and biodiversity loss.
High population densities make pandemics more likely. They also drive overcrowding, unemployment, housing shortages and deteriorating infrastructure, and can spark conflicts leading to insurrections, terrorism, and war.
High-consuming countries like Australia, Canada and the US use multiple units of fossil-fuel energy to produce one energy unit of food. Energy consumption will therefore increase in the near future, especially as the global middle class grows.
Then there’s climate change. Humanity has already exceeded global warming of 1°C this century, and will almost assuredly exceed 1.5 °C between 2030 and 2052. Even if all nations party to the Paris Agreement ratify their commitments, warming would still reach between 2.6°C and 3.1°C by 2100.
The danger of political impotence
Our paper found global policymaking falls far short of addressing these existential threats. Securing Earth’s future requires prudent, long-term decisions. However this is impeded by short-term interests, and an economic system that concentrates wealth among a few individuals.
Right-wing populist leaders with anti-environment agendas are on the rise, and in many countries, environmental protest groups have been labelled “terrorists”. Environmentalism has become weaponised as a political ideology, rather than properly viewed as a universal mode of self-preservation.
revealing the true cost of products and activities by forcing those who damage the environment to pay for its restoration, such as through carbon pricing
rapidly eliminating fossil fuels
regulating markets by curtailing monopolisation and limiting undue corporate influence on policy
reigning in corporate lobbying of political representatives
educating and empowering women across the globe, including giving them control over family planning.
Don’t look away
Many organisations and individuals are devoted to achieving these aims. However their messages have not sufficiently penetrated the policy, economic, political and academic realms to make much difference.
Failing to acknowledge the magnitude and gravity of problems facing humanity is not just naïve, it’s dangerous. And science has a big role to play here.
Scientists must not sugarcoat the overwhelming challenges ahead. Instead, they should tell it like it is. Anything else is at best misleading, and at worst potentially lethal for the human enterprise.
To limit the spread of disease and reduce environmental pollution, human waste (excreta) needs to be safely contained and effectively treated. Yet 4.2 billion people, more than half of the world’s population, lack access to safe sanitation.
In developing countries, each person produces, on average, six litres of toilet wastewater each day. Based on the number of people who don’t have access to safe sanitation, that equates to nearly 14 billion litres of untreated faecally contaminated wastewater created each day. That’s the same as 5,600 Olympic-sized swimming pools.
This untreated wastewater directly contributes to increased diarrhoeal diseases, such as cholera, typhoid fever and rotavirus. Diseases such as these are responsible for 297,000 deaths per year of children under five years old, or 800 children every day.
The highest rates of diarrhoea-attributable child deaths are experienced by the poorest communities in countries including Afghanistan, India, and the Democratic Republic of Congo.
Given the global scale of this problem, it’s surprising sanitation practitioners still don’t know where exactly all the human excreta flows or leaches to, due to absent or unreliable data.
Poor sanitation to worsen under climate change
Inadequate sanitation is not only a human health issue, it’s also bad for the environment. An estimated 80% of wastewater from developed and developing countries flows untreated into environments around the world.
If an excess of nutrients (such as nitrogen and phosphorous) are released into the environment from untreated wastewater, it can foul natural ecosystems and disrupt aquatic life.
This is especially the case for coral reefs. Many of the worlds most diverse coral reefs are located in tropical developing countries.
And overwhelmingly, developing countries have very limited human excreta management, leading to large quantities of raw wastewater being released directly onto coral reefs. In countries with high populations such as Indonesia and the Philippines, this is particularly evident.
The damage raw wastewater inflicts on corals is severe. Raw wastewater carries solids, endocrine disrupters (chemicals that interfere with hormones), inorganic nutrients, heavy metals and pathogens directly to corals. This stunts coral growth, causes more coral diseases and reduces their reproduction rates.
The challenges of climate change will exacerbate our sanitation crisis, as increased rain and flooding will inundate sanitation systems and cause them to overflow. Pacific Island nations are particularly vulnerable, because of the compounding impacts of rising sea levels and more frequent, extreme tropical cyclones.
Meanwhile, increased drought and severe water scarcity in other parts of the world will render some sanitation systems, such as sewer systems, inoperable. One example is the mismanagement of government-operated water supplies in Harare, Zimbabwe leading to the failure of the sewerage system and placing millions at risk of waterborne diseases.
Even in more developed countries like Australia, increased frequency of extreme weather events and disasters, including bushfires, will damage some sanitation infrastructure beyond repair.
Global targets to improve sanitation
Improving clean water and sanitation have clear global targets. Goal 6 of the United Nation’s sustainable development goals is to, by 2030, achieve adequate and equitable sanitation for all and to halve the proportion of untreated wastewater.
Achieving this target will be difficult, given there is an absence of reliable data on the exact numbers of sanitation systems that are safely managed or not, particularly in developing countries.
Individual studies in countries such as Tanzania provide small amounts of information on whether some sanitation systems are safely managed. But these studies are not yet at the size needed to extrapolate to national scales.
A big reason behind the missing data is the large range of sanitation systems and their complex classifications.
For example, in developing countries, most people are serviced by on-site sanitation such as septic tanks (a concrete tank) or pit latrines (hole dug into the ground). But a lack of adherence to construction standards in nearly all developing countries, means most septic tanks are not built to standard and do not safely contain or treat faecal sludge.
A common example seen with septic tank construction is there are a lot of incentives to build “non-standard” septic tanks that are much cheaper. From my current research in rural Fiji, I’ve seen reduced tank sizes and the use of alternative materials (old plastic water tanks) to save space and money in material costs.
These don’t allow for adequate containment or treatment. Instead, excreta can leach freely into the surrounding environment.
A standard septic tank is designed to be desludged periodically, where the settled solids at the bottom of the tanks are removed by large vacuum trucks and disposed of safely. So, having a non-standard septic tank is further incentivised as the lack of sealed chambers reduces the accumulation of sludge, delaying costly emptying fees.
Another key challenge with data collection is how to determine if the sanitation infrastructure if functioning correctly. Even if the original design was built to a quality standard, in many circumstances there are significant deficiencies in operational and maintenance activities that lead to the system not working properly.
What’s more, terminology is a constant point of confusion. Households — when surveyed for UN’s Sustainable Development Goal data collection on sanitation — will say they do have a septic tank. But in reality, they’re unaware they have a non-standard septic tank functioning as a leach-pit, and not safely treating or containing their excreta.
Fixing the problem
Achieving the Sustainable Development Goal 6 requires nationally representative data sets. The following important questions must be answered, at national scales in developing countries:
for every toilet, where does the excreta go? Is it safely contained, treated on site, or transported for treatment?
if the excreta is not contained or treated properly after it leaves the toilet, then how far does it travel through the ground or waterways?
when excreta is removed from the pit or septic tank of a full on-site latrine, where is it taken? Is it dumped in the environment or safely treated?
are sewer systems intact and connected to functioning wastewater treatment plants that releases effluent (treated waste) of a safe quality?
Presently, the sanitation data collection tools the UN uses for its Sustainable Development Goals don’t answer in full these critical questions. More robust surveys and sampling programs need to be designed, along with resource allocation for government sanitation departments for a more thorough data collection strategy.
And importantly, we need a co-ordinated investment in sustainable sanitation solutions from all stakeholders, especially governments, international organisations and the private sector. This is essential to both protect the health of our own species and all other living things.
How do we save whales and other marine animals from plastic in the ocean? Our new review shows reducing plastic pollution can prevent the deaths of beloved marine species. Over 700 marine species, including half of the world’s cetaceans (such as whales and dolphins), all of its sea turtles and a third of its seabirds, are known to ingest plastic.
When animals eat plastic, it can block their digestive system, causing a long, slow death from starvation. Sharp pieces of plastic can also pierce the gut wall, causing infection and sometimes death. As little as one piece of ingested plastic can kill an animal.
About eight million tonnes of plastic enters the ocean each year, so solving the problem may seem overwhelming. How do we reduce harm to whales and other marine animals from that much plastic?
Like a hospital overwhelmed with patients, we triage. By identifying the items that are deadly to the most vulnerable species, we can apply solutions that target these most deadly items.
We tested these expert predictions by assessing data from 76 published research papers incorporating 1,328 marine animals (132 cetaceans, 20 seals and sea lions, 515 sea turtles and 658 seabirds) from 80 species.
We examined which items caused the greatest number of deaths in each group, and also the “lethality” of each item (how many deaths per interaction). We found the experts got it right for three of four items.
Flexible plastics, such as plastic sheets, bags and packaging, can cause gut blockage and were responsible for the greatest number of deaths over all animal groups. These film plastics caused the most deaths in cetaceans and sea turtles. Fishing debris, such as nets, lines and tackle, caused fatalities in larger animals, particularly seals and sea lions.
Turtles and whales that eat debris can have difficulty swimming, which may increase the risk of being struck by ships or boats. In contrast, seals and sea lions don’t eat much plastic, but can die from eating fishing debris.
Balloons, ropes and rubber, meanwhile, were deadly for smaller fauna. And hard plastics caused the most deaths among seabirds. Rubber, fishing debris, metal and latex (including balloons) were the most lethal for birds, with the highest chance of causing death per recorded ingestion.
The most cost-efficient way to reduce marine megafauna deaths from plastic ingestion is to target the most lethal items and prioritise their reduction in the environment.
Targeting big plastic items is also smart, as they can break down into smaller pieces. Small debris fragments such as microplastics and fibres are a lower management priority, as they cause significantly fewer deaths to megafauna and are more difficult to manage.
Flexible film-like plastics, including plastic bags and packaging, rank among the ten most common items in marine debris surveys globally. Plastic bag bans and fees for bags have already been shown to reduce bags littered into the environment. Improving local disposal and engineering solutions to enable recycling and improve the life span of plastics may also help reduce littering.
Lost fishing gear is particularly lethal. Fisheries have high gear loss rates: 5.7% of all nets and 29% of all lines are lost annually in commercial fisheries. The introduction of minimum standards of loss-resistant or higher quality gear can reduce loss.
incentivising gear repairs and port disposal of damaged nets
penalising or prohibiting high-risk fishing activities where snags or gear loss are likely
and enforcing penalties associated with dumping.
Outreach and education to recreational fishers to highlight the harmful effects of fishing gear could also have benefit.
Balloons, latex and rubber are rare in the marine environment, but are disproportionately lethal, particularly to sea turtles and seabirds. Preventing intentional balloon releases and accidental release during events and celebrations would require legislation and a shift in public will.
The Pacific Ocean is the deepest, largest ocean on Earth, covering about a third of the globe’s surface. An ocean that vast may seem invincible. Yet across its reach – from Antarctica in the south to the Arctic in the north, and from Asia to Australia to the Americas – the Pacific Ocean’s delicate ecology is under threat.
In most cases, human activity is to blame. We have systematically pillaged the Pacific of fish. We have used it as a rubbish tip – garbage has been found even in the deepest point on Earth, in the Mariana Trench 11,000 metres below sea level.
And as we pump carbon dioxide into the atmosphere, the Pacific, like other oceans, is becoming more acidic. It means fish are losing their sense of sight and smell, and sea organisms are struggling to build their shells.
Oceans produce most of the oxygen we breathe. They regulate the weather, provide food, and give an income to millions of people. They are places of fun and recreation, solace and spiritual connection. So, healthy, vibrant oceans benefit us all. And by better understanding the threats to the precious Pacific, we can start the long road to protecting it.
The series opens with five profiles delving into ancient Indian Ocean trade networks, Pacific plastic pollution, Arctic light and life, Atlantic fisheries and the Southern Ocean’s impact on global climate. It’s brought to you by The Conversation’s international network.
The ocean plastic scourge
The problem of ocean plastic was scientifically recognised in the 1960s after two scientists saw albatross carcasses littering the beaches of the northwest Hawaiian Islands in the northern Pacific. Almost three in four albatross chicks, who died before they could fledge, had plastic in their stomachs.
Now, plastic debris is found in all major marine habitats around the world, in sizes ranging from nanometers to meters. A small portion of this accumulates into giant floating “garbage patches”, and the Pacific Ocean is famously home to the largest of them all.
Plastic debris in the oceans presents innumerable hazards for marine life. Animals can get tangled in debris such as discarded fishing nets, causing them to be injured or drown.
Some organisms, such as microscopic algae and invertebrates, can also hitch a ride on floating debris, travelling large distances across the oceans. This means they can be dispersed out of their natural range, and can colonise other regions as invasive species.
And of course, wildlife can be badly harmed by ingesting debris, such as microplastics less than five millimetres in size. This plastic can obstruct an animal’s mouth or accumulate in its stomach. Often, the animal dies a slow, painful death.
Seabirds, in particular, often mistake floating plastics for food. A 2019 study found there was a 20% chance seabirds would die after ingesting a single item, rising to 100% after consuming 93 items.
And since floating plastics in the open ocean are transported mainly by ocean surface currents and winds, plastic debris accumulates on island coastlines along their path. Kamilo Beach, on the south-eastern tip of Hawaii’s Big Island, is considered one of the world’s worst for plastic pollution. Up to 20 tonnes of debris wash onto the beach each year.
Similarly, on uninhabited Henderson Island, part of the Pitcairn Island chain in the south Pacific, 18 tonnes of plastic have accumulated on a beach just 2.5km long. Several thousand pieces of plastic wash up each day.
Subtropical garbage patches
Plastic waste can have different fates in the ocean: some sink, some wash up on beaches and some float on the ocean surface, transported by currents, wind and waves.
Around 1% of plastic waste accumulates in five subtropical “garbage patches” in the open ocean. They’re formed as a result of ocean circulation, driven by the changing wind fields and the Earth’s rotation.
There are two subtropical garbage patches in the Pacific: one in the northern and one in the southern hemisphere.
The northern accumulation region is separated into an eastern patch between California and Hawaii, and a western patch, which extends eastwards from Japan.
Our ocean garbage shame
First discovered by Captain Charles Moore in the early 2000s, the eastern patch is better known as the Great Pacific Garbage Patch because it’s the largest by both size (around 1.6 million square kilometers) and amount of plastic. By weight, this garbage patch can hold more than 100 kilograms per square kilometre.
The garbage patch in the southern Pacific is located off Valparaiso, Chile, extending to the west. It has lower concentrations compared to its giant counterpart in the northeast.
Discarded fishing nets make up around 45% of the total plastic weight in the Great Pacific Garbage Patch. Waste from the 2011 Japan tsunami is also a major contributor, making up an estimated 20% of the patch.
Each year, up to 15 million tonnes of plastic waste are estimated to make their way into the ocean from coastlines and rivers. This amount is expected to double by 2025 as plastic production continues to increase.
We must act urgently to stem the flow. This includes developing plans to collect and remove the plastics and, vitally, stop producing so much in the first place.
Fisheries on the verge of collapse
As the largest and deepest sea on Earth, the Pacific supports some of the world’s biggest fisheries. For thousands of years, people have relied on these fisheries for their food and livelihoods.
But, around the world, including in the Pacific, fishing operations are depleting fish populations faster than they can recover. This overfishing is considered one of the most serious threats to the world’s oceans.
Humans take about 80 million tonnes of wildlife from the sea each year. In 2019, the world’s leading scientists said of all threats to marine biodiversity over the past 50 years, fishing has caused the most harm. They said 33% of fish species were overexploited, 60% were being fished to the maximum level, and just 7% were underfished.
The decline in fish populations is not just a problem for humans. Fish play an important role in marine ecosystems and are a crucial link in the ocean’s complex food webs.
Not plenty of fish in the sea
Overfishing happens when humans extract fish resources beyond the maximum level, known as the “maximum sustainable yield”. Fishing beyond this causes global fish stocks to decline, disrupts food chains, degrades habitats, and creates food scarcity for humans.
The Pacific Ocean is home to huge tuna fisheries, which provide almost 65% of the global tuna catch each year. But the long-term survival of many tuna populations is at risk.
For example, a study released in 2013 found numbers of bluefin tuna – a prized fish used to make sushi – had declined by more than 96% in the Northern Pacific Ocean.
Developing countries, including Indonesia and China, are major overfishers, but so too are developing nations.
Along Canada’s west coast, Pacific salmon populations have declined rapidly since the early 1990s, partly due to overfishing. And Japan was recently heavily criticised for a proposal to increase quotas on Pacific bluefin tuna, a species reportedly at just 4.5% of its historic population size.
Experts say overfishing is also a problem in Australia. For example, research in 2018 showed large fish species were rapidly declining around the nation due to excessive fishing pressure. In areas open to fishing, exploited populations fell by an average of 33% in the decade to 2015.
So what’s driving overfishing?
There are many reasons why overfishing occurs and why it is goes unchecked. The evidence points to:
Let’s take Indonesia as an example. Indonesia lies between the Pacific and Indian oceans and is the world’s third-biggest producer of wild-capture ﬁsh after China and Peru. Some 60% of the catch is made by small-scale ﬁshers. Many hail from poor coastal communities.
Overfishing was first reported in Indonesia in the 1970s. It prompted a presidential decree in 1980, banning trawling off the islands of Java and Sumatra. But overfishing continued into the 1990s, and it persists today. Target species include reef fishes, lobster, prawn, crab, and squid.
Indonesia’s experience shows how there is no easy fix to the overfishing problem. In 2017, the Indonesian government issued a decree that was supposed to keep fishing to a sustainable level – 12.5 million tonnes per year. Yet, in may places, the practice continued – largely because the rules were not clear and local enforcement was inadequate.
Implementation was complicated by the fact that almost all Indonesia’s smaller fishing boats come under the control of provincial governments. This reveals the need for better cooperation between levels of government in cracking down on overfishing.
What else can we do?
To prevent overfishing, governments should address the issue of poverty and poor education in small fishing communities. This may involve finding them a new source of income. For example in the town of Oslob in the Philippines, former fishermen and women have turned to tourism – feeding whale sharks tiny amounts of krill to draw them closer to shore so tourists can snorkel or dive with them.
Tackling overfishing in the Pacific will also require cooperation among nations to monitor fishing practices and enforce the rules.
And the world’s network of marine protected areas should be expanded and strengthened to conserve marine life. Currently, less than 3% of the world’s oceans are highly protected “no take” zones. In Australia, many marine reserves are small and located in areas of little value to commercial fishers.
The collapse of fisheries around the world shows just how vulnerable our marine life is. It’s clear that humans are exploiting the oceans beyond sustainable levels. Billions of people rely on seafood for protein and for their livelihoods. But by allowing overfishing to continue, we harm not just the oceans, but ourselves.
The tropical and subtropical waters of the Pacific Ocean are home to more than 75% of the world’s coral reefs. These include the Great Barrier Reef and more remote reefs in the Coral Triangle, such as those in Indonesia and Papua New Guinea.
Coral reefs are bearing the brunt of climate change. We hear a lot about how coral bleaching is damaging coral ecosystems. But another insidious process, ocean acidification, is also threatening reef survival.
Ocean acidification particularly affects shallow waters, and the subarctic Pacific region is particularly vulnerable.
Coral reefs cover less than 0.5% of Earth’s surface, but house an estimated 25% of all marine species. Due to ocean acidification and other threats, these incredibly diverse “underwater rainforests” are among the most threatened ecosystems on the planet.
A chemical reaction
Ocean acidification involves a decrease in the pH of seawater as it absorbs carbon dioxide (CO₂) from the atmosphere.
Each year, humans emit 35 billion tonnes of CO₂ through activities such as burning of fossil fuels and deforestation.
Oceans absorb up to 30% of atmospheric CO₂, setting off a chemical reaction in which concentrations of carbonate ions fall, and hydrogen ion concentrations increase. That change makes the seawater more acidic.
Ocean acidification is also a problem for the fishes. Many studies have revealed elevated CO₂ can disrupt their sense of smell, vision and hearing. It can also impair survival traits, such as a fish’s ability to learn, avoid predators, and select suitable habitat.
However, ocean acidification does not affect all marine species in the same way, and the effects can vary over the organism’s lifetime. So, more research to predict the future winners and losers is crucial.
This can be done by identifying inherited traits that can increase an organism’s survival and reproductive success under more acidic conditions. Winner populations may start to adapt, while loser populations should be targets for conservation and management.
One such winner may be the epaulette shark, a shallow water reef species endemic to the Great Barrier Reef. Research suggests simulated ocean acidification conditions do not impact early growth, development, and survival of embryos and neonates, nor do they affect foraging behaviours or metabolic performance of adults.
But ocean acidification is also likely to create losers on the Great Barrier Reef. For example, researchers studying the orange clownfish – a species made famous by Disney’s animated Nemo character – found they suffered multiple sensory impairments under simulated ocean acidification conditions. These ranged from difficulties smelling and hearing their way home, to distinguishing friend from foe.
It’s not too late
More than half a billion people depend on coral reefs for food, income, and protection from storms and coastal erosion. Reefs provide jobs – such as in tourism and fishing – and places for recreation. Globally, coral reefs represent an industry worth US$11.9 trillion per year. And importantly, they’re a place of deep cultural and spiritual connection for Indigenous people around the world.
Cutting greenhouse gas emissions must become a global mission. COVID-19 has slowed our movements across the planet, showing it’s possible to radically slash our production of CO₂. If the world meets the most ambitious goals of the Paris Agreement and keeps global temperature increases below 1.5℃, the Pacific will experience far less severe decreases in oceanic pH.
We will, however, have to curb emissions by a lot more – 45% over the next decade – to keep global warming below 1.5℃. This would give some hope that coral reefs in the Pacific, and worldwide, are not completely lost.
Clearly, the decisions we make today will affect what our oceans look like tomorrow.
In my career as a marine biologist, I’ve been fortunate enough to visit some of the most remote islands in the world. These beautiful places continue to remind me why I have this job in the first place, but they also bring home the pervasive influence of human societies. Uninhabited bird colonies on the Canadian West Coast, remote tropical Japanese islands, and tiny bits of land in South East Asia all have one thing in common: plastic waste on the beach.
When at home in Sweden, I regularly swim and sail in the Baltic Sea. But agricultural fertilisers and other types of pollution have created dead zones where fish either leave or suffocate. Meanwhile, offshore fisheries and aquaculture farms in many parts of the world overharvest and pollute the water. We know what proper management of these activities could look like, but political will has so far not been equal to the challenge.
That may be about to change. A recent agreement between 14 heads of state – together representing 40% of the world’s coastline – promised to end overfishing, restore fish stocks and halt the flow of plastic pollution into the ocean within a decade.
Pollution, plastics and unsustainable seafood may look like isolated problems, but they influence each other. As nutrients run off farmland and into the sea, they affect the conditions fish need to thrive. Pollution makes our seafood less healthy and overfishing is pushing some fish stocks beyond their capacity to renew themselves.
It’s in everyone’s interests to protect the ocean. Clean seas would be more profitable and research suggests that better managed fisheries could generate six times more food than they do currently. The exclusive economic zones of coastal states would be more productive if every country agreed to protect the high seas. And sailing in the Baltic Sea would be much nicer if the boat didn’t have to plough a thick, green sludge.
So how can the world make progress – and what’s holding us back?
As part of the recent agreement between 14 heads of state, the participating countries – Australia, Canada, Chile, Fiji, Ghana, Indonesia, Jamaica, Japan, Kenya, Mexico, Namibia, Norway, Palau and Portugal – committed to a number of goals within their national waters, including investment in zero-emission shipping, eliminating waste and ensuring fisheries are sustainable. The aim is to ensure all activity within these exclusive economic zones is sustainable by 2025.
The countries agreed to fast-track their plan for action, rather than work through the UN. Their combined national waters roughly equal the size of Africa. They each have clear stakes in the continued functioning of ocean ecosystems and economies, so this pragmatic approach makes sense. That’s a sentiment that businesses could no doubt respect. After all, there are no economic opportunities in a dead ocean.
The agreement is an encouraging message from political leaders, and these states can leverage vast sums of money and resources to effect change. But the ocean is home to a dozen global industries, and around 50,000 vessels traverse it at any one time. Clearly, we need more than governments to deliver on this ambitious agenda.
My scientific colleagues and I have been developing a global coalition of businesses concerned with sustainable seafood. Our strategy is to find “keystone actors” within the private sector – companies with a disproportionate ability to influence change due to their size and strength.
The seafood industry is vast, and includes some of the largest companies in the world – from entire fisheries, to aquaculture farms and feed processors. After four years of working together, change within the participating companies is accelerating. For example, Nissui, the world’s second-largest seafood company, has evaluated their entire production portfolio for sustainability challenges.
Collaboration between scientists and businesses is vital to delivering commitments made by governments. Scientists can help define the problems, and business can develop, pilot and scale solutions. For instance, we’re developing software that can automatically detect which species of fish are caught on vessels, to radically improve the transparency of seafood production.
The ocean has been a source of inspiration, imagination and adventure since the beginning of time. It has fed us and generated livelihoods for billions. Politicians have stood serenely on the sidelines for some time now, content to be passive observers of deteriorating ecosystems. But the era of passive observation may finally be coming to an end.
Freshwater ecosystems are a priority for environmental scientists because they affect the health of animals and plants on land too – as well as people. They provide food, water, transport and flood control. Freshwater ecosystems also keep nutrients moving among organisms and support diverse forms of life.
Freshwater systems make a big difference to the quality of life in any human society. But they are under great pressure. Freshwater biodiversity is declining faster than terrestrial biodiversity.
One of the biggest stresses on freshwater ecosystems is the presence of plastics. Some microplastics – tiny pieces of plastic that have broken down from bigger pieces – get into water from various sources. Some are introduced from industrial sources like cosmetics, toothpaste and shaving cream. Another major source is dumping of plastic waste like bags and bottles.
In Nigeria, an important source is the plastic sachets that contain drinking water. Over 60 million of these are consumed in a day.
Ultimately all these types of plastic waste find their way to the aquatic environment. There they stay in the water column, settle on river beds or are ingested by aquatic animals.
My research group set out to assess the load and chemical nature of microplastics in two important rivers and Gulf of Guinea tributaries in Nigeria. We looked for the presence of microplastics in aquatic insects since they often dominate aquatic animal life. Most also spend their adult stage in the terrestrial environment, once they emerge from their larvae. We found that microplastics were present in large quantities in the insect larvae. The insects are part of a food chain and could transfer the harmful effects of microplastics throughout the chain.
This further reinforces the urgent need for Nigeria to go ahead with measures to reduce the use of plastic bags and single-use plastics.
The research findings
We used three of the rivers’ aquatic insect species as bio-indicators and found that all three had ingested microplastics from the two rivers. The ingested microplastics include styrene-ethylene-butylene-styrene, acrylonitrile butadiene styrene, chlorinated polyethylene, polypropylene, and polyester. The quantity of microplastics ingested by the insects was fairly high, especially in the Chironomus sp. which is a riverbed dweller recorded in the Ogun River.
The diversity of plastic polymers recorded in these insects suggests a wide range of applications of plastics in Nigeria.
The three insect species spend their larval stages in the water and later migrate to land in the adult phase. The concern is that the insect larvae could serve as a link for microplastics’ transfer to higher trophic levels in the aquatic environment. Also, the adults serve in the same capacity in the terrestrial environment. A trophic level is the group of organisms within an ecosystem which occupy the same level in a food chain.
Dragonfly larvae in the water are eaten by fish, salamanders, turtles, birds and beetles. Adult dragonflies on land are also eaten by birds and other insects.
Through feeding, the transfer of microplastics in the environment could go as far as people – who caused the plastic pollution in the first place.
Evidence suggests that microplastics reduce the physiological fitness of animals. This comes through decreased food consumption, weight loss, decreased growth rate, energy depletion and susceptibility to other harmful substances. Human health could similarly be at risk on account of microplastic ingestion.
A ban on plastic bags would curb the plastic pollution in Nigeria. There are alternatives to the use of plastic bags, for instance, bags made from banana stalks, coconut, palm leaf, cassava flour and chicken feathers. Unlike plastic bags, which could persist in the environments for over a century, bags made from these organic materials decompose readily in a manner that does not pose a health risk to the environment.
For a long while, the call to mitigate plastic pollution was not heeded in Nigeria. Recently, the House of Representatives passed a bill banning plastic bags. But this is yet to be implemented as the president has not assented to it.
A study in the European Union indicates that a ban on single-use plastics could reduce marine plastic pollution by about 5.5%.
It is about time Nigeria treated plastic pollution as a national emergency, considering its implications for human health and the ecological integrity of aquatic ecosystems. An approach that puts people at the centre of the issue has been suggested as one way to convince local communities to preserve the integrity of the environment.
Perhaps this approach could help restore plastic-laden aquatic ecosystems and preserve the pristine ones.
Many of us are aware of the enormous threat of antibiotic- (or “antimicrobial”) resistant bacteria on human health. But few realise just how pervasive these superbugs are — antimicrobial-resistant bacteria have jumped from humans and are running rampant across wildlife and the environment.
My research is revealing the enormous breadth of wildlife species with superbugs in their gut bacterial communities (“microbiome”). Affected wildlife includes little penguins, sea lions, brushtailed possums, Tassie devils, flying foxes, echidnas, and a range of kangaroo and wallaby species.
Humans have solely driven the emergence and spread of antimicrobial-resistant bacteria, mainly through the overuse, and often misuse, of antibiotics.
The spread of superbugs to the environment has mainly occurred through human wastewater. Medical and industrial waste, which pollute the environment with the antibiotics themselves, worsen the issue. And the ability for antibiotic-resistant genes to be shared between bacteria in the environment has propelled antimicrobial resistance even further.
Generally, wildlife closer to people in urban areas are more likely to carry antimicrobial-resistant bacteria, because we share our homes, food waste and water with them.
For example, our recent research showed 48% of 664 brushtail possums around Sydney and Melbourne tested positive for antibiotic-resistant genes.
Whether animals are in captivity or the wild also plays a role in their levels of antimicrobial resistance.
For example, we found only 5.3% of grey-headed flying-foxes in the wild were carrying resistance traits. This jumps to 41% when flying-foxes are in wildlife care or captivity.
Likewise, less than 2% of wild Australian sea lions we tested had antibiotic-resistant bacteria, compared to more than 40% of those in captivity. We’ve found similar trends between captive and wild little penguins, too.
And more than 40% of brush-tailed rock wallabies in a captive breeding program were carrying antibiotic resistance genes compared to none from the wild.
So why is this a problem?
An animal with antibiotic-resistant bacteria may be harder to treat with antibiotics if it’s injured or sick and ends up in care. But generally, we’re yet to understand their full impact – though we can speculate.
For wildlife, resistant bacteria are essentially “weeds” in their microbiomes. These microbial weeds may disrupt the microbiomes, impairing immunity or increasing the risk of infection by other agents.
Another problem relates to how antimicrobial-resistant bacteria can spread their resistant genes to other bacteria. Sharing genes between bacteria is a major driver for new resistant bacterial strains.
We’ve been finding more types of resistant genes in an animal’s microbiome than we do in comparison to commonly studied bacteria, such as Escherichia coli. This means some wildlife bacteria may have acquired resistance genes, but we don’t know which.
Many of the wildlife species we’ve examined also carry human-associated bacterial strains — strains known to cause, for instance, diarrhoeal disease in humans. In wildlife, these bacteria could potentially acquire novel resistance genes making them harder to treat if they spread back to people.
This is something we found in grey-headed flying-fox microbiomes, which had new combinations of resistant genes. These, we concluded, originated from the outside environment.
How do we mitigate this threat?
Antimicrobial stewardship — using the best antibiotic when a bacterial infection is diagnosed, and using it appropriately — is a big part of tackling this global health issue.
The 2020 strategy builds on a previous strategy by better incorporating the environment, in what should be a true “One Health” approach. The World Health Organisation’s appointment of Ley supports this.
Antimicrobial stewardship is equally important for those in veterinary fields as well as medical doctors. As Australia leads the world in wildlife rehabilitation, antimicrobial stewardship should be a major part of wildlife care.
For the rest of us, preventing our superbugs from spilling over to wildlife also starts with taking antibiotics appropriately, and recognising antibiotics work only for bacterial infections. It’s also worth noting you should find a toilet if you’re out in the bush (and not “go naturally”), and not leave your food scraps behind for wild animals to find.
The 2020 strategy recognises the need for better communication to strengthen stewardship and awareness. This should include education on the issues of antimicrobial resistance, what it means for wildlife health, and how to mitigate it.
This is something my colleagues and I are tackling through our citizen science project, Scoop a Poop, where we work with school children, community groups and wildlife carers who collect possum poo around the country to help us better understand antimicrobial resistance in the wild.
The power of working with citizens to better the health of our environment cannot be overstated.
Like many inventions, the discovery of Teflon happened by accident. In 1938, chemists from Dupont (now Chemours) were studying refrigerant gases when, much to their surprise, one concoction solidified. Upon investigation, they found it was not only the slipperiest substance they’d ever seen – it was also noncorrosive and extremely stable and had a high melting point.
In 1954 the revolutionary “nonstick” Teflon pan was introduced. Since then, an entire class of human-made chemicals has evolved: per- and polyfluoroalkyl substances, better known as PFAS. There are upward of 6,000 of these chemicals. Many are used for stain-, grease- and waterproofing. PFAS are found in clothing, plastic, food packaging, electronics, personal care products, firefighting foams, medical devices and numerous other products.
But over time, evidence has slowly built that some commonly used PFAS are toxic and may cause cancer. It took 50 years to understand that the happy accident of Teflon’s discovery was, in fact, a train wreck.
Typically, when the U.S. Environmental Protection Agency assesses chemicals for potential harm, it examines one substance at a time. That approach isn’t working for PFAS, given the sheer number of them and the fact that manufacturers commonly replace toxic substances with “regrettable substitutes” – similar, lesser-known chemicals that also threaten human health and the environment.
A class-action lawsuit brought this issue to national attention in 2005. Workers at a Parkersburg, West Virginia, DuPont plant joined with local residents to sue the company for releasing millions of pounds of one of these chemicals, known as PFOA, into the air and the Ohio River. Lawyers discovered that the company had known as far back as 1961 that PFOA could harm the liver.
The suit was ultimately settled in 2017 for US$670 million, after an eight-year study of tens of thousands of people who had been exposed. Based on multiple scientific studies, this review concluded that there was a probable link between exposure to PFOA and six categories of diseases: diagnosed high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer and pregnancy-induced hypertension.
PFAS are often called “forever chemicals” because they don’t fully degrade. They move easily through air and water, can quickly travel long distances and accumulate in sediment, soil and plants. They have also been found in dustand food, including eggs, meat, milk, fish, fruits and vegetables.
Children are even more vulnerable than adults because they can ingest more PFAS relative to their body weight from food and water and through the air. Children also put their hands in their mouths more often, and their metabolic and immune systems are less developed. Studies show that these chemicals harm children by causing kidney dysfunction, delayed puberty, asthma and altered immune function.
PFAS have become so ubiquitous in the environment that health experts say it is probably impossible to completely prevent exposure. These substances are released throughout their life cycles, from chemical production to product use and disposal. Up to 80% of environmental pollution from common PFAS, such as PFOA, comes from production of fluoropolymers that use toxic PFAS as processing aids to make products like Teflon.
In 2009 the EPA established a health advisory level for PFOA in drinking water of 400 parts per trillion. Health advisories are not binding regulations – they are technical guidelines for state, local and tribal governments, which are primarily responsible for regulating public water systems.
I am part of a group of scientists from universities, nonprofit organizations and government agencies in the U.S. and Europe that has argued for managing the entire class of PFAS chemicals as a group, instead of one by one. We also support an “essential uses” approach that would restrict their production and use only to products that are critical for health and proper functioning of society, such as medical devices and safety equipment. And we have recommended developing safer non-PFAS alternatives.
As the EPA acknowledges, there is an urgent need for innovative solutions to PFAS pollution. Guided by good science, I believe we can effectively manage PFAS to reduce further harm, while researchers find ways to clean up what has already been released.
But just how bad is the problem? Our new research provides the first global estimate of microplastics on the seafloor — our research suggests there’s a staggering 8-14 million tonnes of it.
This is up to 35 times more than the estimated weight of plastic pollution on the ocean’s surface.
What’s more, plastic production and pollution is expected to increase in coming years, despite increased media, government and scientific attention on how plastic pollution can harm marine ecosystems, wildlife and human health.
These findings are yet another wake-up call. When the plastic we use in our daily lives reaches even the deepest oceans, it’s more urgent than ever to find ways to clean up our mess before it reaches the ocean, or to stop making so much of it in the first place.
Breaking down larger plastic
Our estimate of microplastics on the seafloor is huge, but it’s still a fraction of the amount of plastic dumped into the ocean. Between 4-8 million tonnes of plastic are thought to enter the sea each and every year.
Most of the plastic dumped into the ocean likely ends up on the coasts, not floating around the ocean’s surface or on the seafloor. In fact, three-quarters of the rubbish found along Australia’s coastlines is plastics.
The larger pieces of plastic that stay in the ocean can deteriorate and break down from weathering and mechanical forces, such as ocean waves. Eventually, this material turns into microplastics, pieces smaller than 5 millimetres in diameter.
Their tiny size means they can be eaten by a variety of marine wildlife, from plankton to crustaceans and fish. And when microplastics enter the marine food web at low levels, it can move up the food chain as bigger species eat smaller ones.
But the problem isn’t as well documented for microplastics on the seafloor. While plastics, including microplastics, have been found in deep-sea sediments in all ocean basins across the world, samples have been small and scarce. This is where our research comes in.
Collecting samples in the Great Australian Bight
We collected samples using a robotic submarine in a range of sea depths, from 1,655 to 3,062 metres, in the Great Australian Bight, up to 380 kilometres offshore from South Australia. The submarine scooped up 51 samples of sand and sediment from the seafloor and we analysed them in a laboratory.
We dried the sediment samples, and found between zero and 13.6 plastic particles per gram. This is up to 25 times more microplastics than previous deep-sea studies. And it’s much higher than studies in other regions, including in the Arctic and Indian Oceans.
While our study looked at one general area, we can scale up to calculate a global estimate of microplastics on the seafloor.
Using the estimated size of the entire ocean — 361,132,000 square kilometres — and the average number and size of particles in our sediment samples, we determined the total, global weight as between 8.4 and 14.4 million tonnes. This range takes into account the possible weights of individual microplastics.
How did the plastic get there?
It’s important to note that since our location was remote, far from any urban population centre, this is a conservative estimate. Yet, we were surprised at just how high the microplastic loads were there.
Few studies have conclusively identified how microplastics travel to their ultimate fate.
Larger pieces of plastic that get broken down to smaller pieces can sink to the seafloor, and ocean currents and the natural movement of sediment along continental shelves can transport them widely.
But not all plastic sinks. A 2016 study suggests interaction with marine organisms is another possible transport method.
Scientists in the US have shown microbial communities, such as bacteria, can inhabit this marine “plastisphere” — a term for the ecosystems that live in plastic environments. The microbes weigh the plastic down so it no longer floats. We also know mussels and other invertebrates may colonise floating plastics, adding weight to make them sink.
For example, in a previous study we found cigarette butts, plastic fragments, bottlecaps and food wrappers are common on land, though rare on the seabed. Meanwhile, we found entangling items such fishing line, ropes and plastic bags are common on the seafloor.
Interestingly, in our new study we also found the number of plastic fragments on the seafloor was generally higher in areas where there was floating rubbish on the ocean’s surface. This suggests surface “hotspots” may be reflected below.
It’s not clear why just yet, but it could be because of the geology and physical features of the seabed, or because local currents, winds and waves result in accumulating zones on the ocean’s surface and the seabed nearby.
Stop using so much plastic
Knowing how much plastic sinks to the ocean floor is an important addition to our understanding of the plastic pollution crisis. But stemming the rising tide of plastic pollution starts with individuals, communities and governments – we all have a role to play.
Reusing, refusing and recycling are good places to start. Seek alternatives and support programs, such as Clean Up Australia Day, to stop plastic waste from entering our environment in the first place, ensuring it doesn’t then become embedded in our precious oceans.
This week, 156 people from the Autonomous Region of Bougainville, in Papua New Guinea, petitioned the Australian government to investigate Rio Tinto over a copper mine that devastated their homeland.
In 1988, disputes around the notorious Panguna mine sparked a lengthy civil war in Bougainville, leading to the deaths of up to 20,000 people. The war is long over and the mine has been closed for 30 years, but its brutal legacy continues.
When I conducted research in Bougainville in 2015, I estimated the deposit of the mine’s waste rock (tailings) downstream from the mine to be at least a kilometre wide at its greatest point. Local residents informed me it was tens of metres deep in places.
I spent several nights in a large two-story house built entirely from a single tree dragged out of the tailings — dragged upright, with a tractor. Every new rainfall brought more tailings downstream and changed the course of the waterways, making life especially challenging for the hundreds of people who eke out a precarious existence panning the tailings for remnants of gold.
The petition has brought the plight of these communities back into the media, but calls for Rio Tinto to clean up its mess have been made for decades. Let’s examine what led to the ongoing crisis.
Triggering a civil war
The Panguna mine was developed in the 1960s, when PNG was still an Australian colony, and operated between 1972 and 1989. It was, at the time, one of the world’s largest copper and gold mines.
It was operated by Bougainville Copper Limited, a subsidiary of what is now Rio Tinto, until 2016 when Rio handed its shares to the governments of Bougainville and PNG.
When a large-scale mining project reaches the end of its commercial life, a comprehensive mine closure and rehabilitation plan is usually put in place.
But Bougainville Copper simply abandoned the site in the face of a landowner rebellion. This was largely triggered by the mine’s environmental and social impacts, including disputes over the sharing of its economic benefits and the impacts of those benefits on predominantly cashless societies.
Following PNG security forces’ heavy-handed intervention — allegedly under strong political pressure from Bougainville Copper — the rebellion quickly escalated into a full-blown separatist conflict that eventually engulfed all parts of the province.
By the time the hostilities ended in 1997, thousands of Bougainvilleans had lost their lives, including from an air and sea blockade the PNG military had imposed, which prevented essential medical supplies reaching the island.
The mine’s gigantic footprint
The Panguna mine’s footprint was gigantic, stretching across the full breadth of the central part of the island.
The disposal of hundreds of millions of tonnes of tailings into the Kawerong-Jaba river system created enormous problems.
Rivers and streams became filled with silt and significantly widened. Water flows were blocked in many places, creating large areas of swampland and disrupting the livelihoods of hundreds of people in communities downstream of the mine. These communities used the rivers for drinking water and the adjacent lands for subsistence food gardening.
Several villages had to be relocated to make way for the mining operations, with around 200 households resettled between 1969 and 1989.
In the absence of any sort of mine closure or “mothballing” arrangements, the environmental and socio-economic impacts of the Panguna mine have only been compounded.
Since the end of mining activities 30 years ago, tailings have continued to move down the rivers and the waterways have never been treated for suspected chemical contamination.
The complainants say by not ensuring its operations didn’t infringe on the local people’s human rights, Rio Tinto breached OECD guidelines for multinational enterprises.
The Conversation contacted Rio Tinto for comment. A spokesperson said:
We believe the 2016 arrangement provided a platform for the Autonomous Bougainville Government (ABG) and PNG to work together on future options for the resource with all stakeholders.
While it is our belief that from 1990 to 2016 no Rio Tinto personnel had access to the mine site due to on-going security concerns, we are aware of the deterioration of mining infrastructure at the site and surrounding areas, and claims of resulting adverse environmental and social, including human rights, impacts.
We are ready to enter into discussions with the communities that have filed the complaint, along with other relevant parties such as BCL and the governments of ABG and PNG.
A long time coming
This week’s petition comes after a long succession of calls for Rio Tinto to be held to account for the Panguna mine’s legacies and the resulting conflict.
A recent example is when, after Rio Tinto divested from Bougainville Copper in 2016, former Bougainville President John Momis said Rio must take full responsibility for an environmental clean-up.
And in an unsuccessful class action, launched by Bougainvilleans in the United States in 2000, Rio was accused of collaborating with the PNG state to commit human rights abuses during the conflict and was also sued for environmental damages. The case ultimately foundered on jurisdictional grounds.
Taking social responsibility
This highlights the enormous challenges in seeking redress from mining companies for their operations in foreign jurisdictions, and, in this case, for “historical” impacts.
The colonial-era approach to mining when Panguna was developed in the 1960s stands in stark contrast to the corporate social responsibility paradigm supposedly governing the global mining industry today.
Indeed, Panguna — along with the socially and environmentally disastrous Ok Tedi mine in the western highlands of PNG — are widely credited with forcing the industry to reassess its “social license to operate”.
It’s clear the time has come for Rio to finally take responsibility for cleaning up the mess on Bougainville.