Editor’s note: Major plastic polluters win as the UN Treaty talks conclude without an agreement. Modern lifestyles and practices are intimately entwined with the use of plastics. Our phones, computers, food packaging, clothes, and even renewable energy technologies, such as wind turbine blades and the cables that connect them to the power grid, are all largely made from plastics. Plastics production requires fossil hydrocarbons and this connection continues to grow stronger daily. Powerful oil producers, both private companies and governments of oil-producing nations, were seen as the key impediment to a consensus deal. What will happen next? “Agree to a treaty among the willing even if that means leaving some countries that don’t want a strong treaty or concede to countries that will likely never join the treaty anyway, failing the planet in the process.”
“Plastic has been found everywhere on Earth — from deepest oceans to high mountains, in clouds and pole to pole. Microplastics have also been found in every place scientists look for them in the human body, from the brain to the testes, breast milk, and artery plaque. Microplastics pose health risks to humans and wildlife, researchers warn.” PFAS(perfluoroalkyl and polyfluoroalkyl substances) – “forever chemicals” contaminate biosolids(waste from sewage) used as fertilizer and pesticides, they also contain heavy metals and nitrates.
Today’s cheerleaders for increased birth rates are well aware of the silent cause of the ongoing rapid decline in male sperm counts. It’s the very industries these corporate managers run and governments regulate that is the blame. So you can be almost 100 percent sure that they are not going to address the real problem in order to achieve the goal of increasing human birth rates.
Laws must mandate companies to reduce their plastic footprint through production reduction, product redesign, or reuse systems — higher-priority strategies in the Zero Waste hierarchy,
Bottlenose dolphins leapt and torpedoed through the shallow turquoise waters off Florida’s Sarasota Bay. Then, a research team moved in, quickly corralling the small pod in a large net.
With the speed of a race car pit crew, veterinarians, biologists and their assistants examined the animals, checking vital signs while taking skin, blood and other samples. They held a petri dish over each dolphin’s blowhole until it exhaled, with an intensity similar to a human cough. Then, they rolled up the net and the dolphins swam off unharmed. A pod in Louisiana’s Barataria Bay was similarly tested.
Generations of dolphins have been part of this ongoing dolphin health study, which has been run by the Sarasota Dolphin Research Program since 1970. It tracks populations and individuals and also looks for health issues related to pollutants in the marine environment.
In the lab, scientists discovered that all 11 of the dolphins had breathed out microplastic fibers, shed from synthetic clothing, says Leslie B. Hart, associate professor at the College of Charleston and an author on this research. The fibers resembled those found in human lungs in previous studies, proving that dolphins, like us, are breathing plastic. In people, microplastic has been linked to poor lung function and possible lung disease.
The dolphin studies are part of a larger quest to understand how plastic pollution is impacting the world’s wildlife. While thousands of human studies have demonstrated damage from tiny plastic particles entering both cells and organs throughout the body, little is known about animal impacts because long-term field studies are difficult and costly. “We’re really just starting to skim the surface,” Hart says.
Beyond the threat plastics pose to individual animals and species, other researchers have detected broader, global harm, a new report warns. Plastic pollution is transforming Earth systems needed to support life, worsening climate change, increasing biodiversity loss, making oceans more acidic and more.
The plastics crisis is escalating rapidly: Each year, petrochemical manufacturers make more than 500 million tons of plastics –– but the world recycles just 9%. The rest is burned, landfilled or ends up in rivers, rainwater, the air, soil or the sea. Today, the planet is awash in plastic. “It’s everywhere. It’s pervasive and it’s persistent,” says Andrew Wargo, who focuses on ecosystem health at the Virginia Institute of Marine Science.
Since the 1930s the polymers industry has completely altered daily life: Plastics are in our homes, cars, clothes, furniture, and electronics, as well as our single-use throwaway water bottles, food packaging and takeout containers.
A critically important fifth round of negotiations begins Nov. 25 when delegates hope to hammer out final treaty language for ratification by U.N. member states.
Meanwhile, the natural world is in great danger, threatened by a biodiversity crisis, a climate crisis and serious degradations of planetary systems. Researchers are now scrambling to understand the growing threat plastics pose to the health of all living organisms.
Plastics conquer the world
Bakelite, the first synthetic plastic product ever made, came on the market in 1907. By the 1950s, production ramped up, changing the course of history and revolutionizing modern life. Plastics facilitated innumerable human innovations — and spawned a throwaway culture. Add in poorly regulated petrochemical manufacturing processes and industrial fishing’s plastic gear, and global plastic pollution stats soared.
Plastic debris was first noticed in the oceans in the early 1960s. For a long time, ecologists’ main wildlife concerns focused on the threat to sea turtles and other marine creatures that ate plastic bags or became tangled in plastic fishing nets. Now, everything from zooplankton to sharks and seabirds eat it and are exposed to it.
Hart emphasizes the problem’s global scope: “Plastic pollution has been found on every continent and in every ocean, in people, terrestrial wildlife and marine wildlife.” It contaminates creatures across the tree of life and concentrates up the food chain, threatening
Seabirds are at particular risk from microplastics, easily mistaking particles for food. Ingestion causes physical and hormonal damage to cells and organs. Image by A_Different_Perspective via Pixabay (Public domain).Image by Alpizar, F., et al. via Wikimedia Commons (CC BY-SA 4.0).
Insidious plastic harm to health
It’s well known that animals regularly mistake plastic debris for food. Shearwaters and other seabirds, for example, can choke and starve when plastic pieces block their digestive tracts or pierce internal organs. At least 1,565 species are known to ingest plastic. For decades, scientists have noted dead animals ensnared in plastic nets, fishing gear or six-pack rings.
But those big pieces of petrochemical plastic (along with their chemical additives) don’t decompose; they degrade into ever-smaller pieces, getting smaller and smaller. Eventually, they break down into microplastics, tiny particles no bigger than a grain of sand, or become nanoparticles, visible only under a high-powered microscope. These microplastics can leach toxic chemicals. Of the more than 13,000 chemicals currently used in plastics, at least 3,200 have one or more “hazardous properties of concern,” according to a U.N. report.
Most of what we know today about the health impacts of plastics and their chemical additives is based on human medical research, which may offer clues to what happens to animals; that’s unlike most health research, which is done on animals and extrapolated to people.
We know from human medical research that microplastics can damage cells and organs and alter hormones that influence their function. Plastic particles have crossed the blood-brain barrier. They have lodged in human bone marrow, testicles, the liver, kidneys and essentially every other part of the body. They enter the placenta, blood and breast milk. Exposure may affect behavior and lower immunity.
And what plastics do to us, they likely do to animals. The phthalates found in Florida dolphins, for example, along with phenols, parabens and per- and polyfluoroalkyls, are just a fraction of the many endocrine disruptors released by plastics and their chemical additives that can alter hormone levels and derail body functions. Exposure may affect behavior and lower immunity.
Plastic does not disappear: It breaks down into smaller and smaller pieces that settle in soil and float in the air and water. Microplastic can easily penetrate living organisms, their cells, and even cross the blood-brain barrier. Image by European Commission (Lukasz Kobus) via Wikimedia Commons (CC BY 4.0).
Doctors have confirmed links between plastic and human disease and disability. “They cause premature birth, low birth weight, and stillbirth as well as leukemia, lymphoma, brain cancer, liver cancer, heart disease and stroke,” Phil Landrigan, a pediatrician and environmental health expert stated in a press conference earlier this year.
In the wild, animals are now exposed daily to microplastics, eating and breathing them, while many freshwater and marine species swim in a plastic soup. But little is known about the long-term impacts of chronic exposure or what microplastics do within animal tissues, with even less understood about what happens when microplastics shrink to nano size and easily enter cells.
In lab experiments, microplastics in the lungs of pregnant rats easily passed to their fetuses’ brains, hearts and other organs. In adult mice, plastic nanoparticles crossed the blood-brain barrier, triggering swift changes that resembled dementia. In a wild animal, cognitive decline can quickly prove fatal, making it difficult to find food, avoid predators, mate or raise young.
In the lab, fish were more susceptible to a common virus after a one-month exposure to microplastic. They then shed more virus (a fish public health problem) and died in high numbers. Surprisingly, “there’s a lot of similarities between fish and humans, so that we have a lot of the same immune pathways,” explains Wargo, an author on this study. However, the reaction depended on the type of plastic. Nylon fibers had the biggest effect; most nylon sheds from synthetic clothing.
Nearly all Laysan albatross (Phoebastria immutabilis) carcasses found on Midway Atoll contain marine plastic debris. Experts estimate that albatrosses feed their chicks approximately 10,000 pounds of marine debris annually on Midway, enough plastic to fill about 100 curbside trash cans. Image by USFWS – Pacific Region via Flickr (CC BY-NC 2.0).
One challenge to researching health impacts, Wargo explains, is that “plastics oftentimes are lumped into one category, but they’re [all] very different: their structure, chemical composition, their shape and size,” creating thousands of variations. These factors influence how toxic they are, he says, which likely varies between individual animals and different species. Investigation is further complicated and obstructed by petrochemical companies that zealously guard their proprietary polymer product formulas.
The ubiquity of plastics and their global presence means that polymers likely have many undetected and unstudied wildlife health impacts. Some impacts could be masked by other environmental stressors, and untangling and analyzing the particulars will likely take decades.
What we do know is that the poor health, decline or disappearance of a single species within a natural community ripples outward, affecting others, and damaging interconnected ecological systems that have evolved in synchrony over millennia. Here’s just one speculative concern: We know microplastics can bioaccumulate, so apex predators, which balance ecosystems by keeping prey species in check, may be at high risk because they consume and build up large concentrations of microplastics and additive chemicals in their organs.
Plastics harm wildlife –– and humans –– in additional ways: by polluting the air and contributing to climate extremes. Currently, about 19% of plastic waste is incinerated, releasing potentially harmful chemical aerosols into the air. In addition, plastic production sends 232 million metric tons of greenhouse gases into the atmosphere yearly. Then there’s the pollution and carbon released from fracking and drilling operations to source the oil and gas to make these products.
Lastly, the microplastics animals and humans ingest are “Trojan horses.” These tiny particles absorb and carry a wide range of pollutants and bacteria, which then can enter and lodge within our bodies.
Single-use plastic bottles and other throwaway plastic packaging are a major cause of plastic pollution, with many activists and nations calling for a ban. While plastic bottles can be recycled, they frequently aren’t. Also, plastics degrade every time they’re recycled and are usually recycled only once or twice. Image by Hans via Pixabay (Public domain).
Stanching ‘a global-scale deluge of plastic waste’
Climate change and the plastics crisis spring from the same source: The world’s seven largest plastic manufacturers are fossil fuel companies. The U.S. produces the most plastic waste of any country, more than the entire EU combined: 42 million metric tons annually, or 287 pounds per person, according to a 2022 congressional report. It noted that “The success of the 20th-century miracle invention of plastics has also produced a global-scale deluge of plastic waste seemingly everywhere we look.”
Consumers can take small actions to protect themselves and limit plastic pollution by avoiding single-use plastics and carrying reusable bags and stainless-steel water bottles. Disposable fast-food packaging makes up almost half of plastic garbage in the ocean, so cutting back on takeout and bottled water could help.
But realistically addressing the planet’s plastics emergency requires a global paradigm shift that reframes the discussion. Many nations still think of plastics as a waste management issue, but responsibility needs to fall on the shoulders of regulators — and the producers, specifically fossil fuel companies and petrochemical manufacturers.
An international consortium of scientists has stressed the need for “urgent action” in the run-up to this month’s United Nations plastics treaty negotiations, the fifth and hopefully final summit intended to establish international regulations.
The U.S. had been among the largest, most influential dissenters in efforts to limit global plastics production and identify hazardous chemicals used in plastics. But in August 2024, prior to the U.S. presidential election, the Biden administration publicly announced it had toughened its position, supporting production limits, but submitted no position paper. Then, this week it returned to its earlier stance that would protect the plastics industry from production caps.
The plastics treaty summit in Busan, South Korea, beginning Nov. 25 and ending Dec. 1, aims to finalize treaty language that will then need to be ratified by the world’s nations. Regardless of the summit’s outcome, scientists continue to uncover new evidence of plastic’s dangers to humans, animals and the planet, raising the alarm and need for action.
This beach on the island of Santa Luzia, Cape Verde, dramatically illustrates a global problem: a world awash in plastic waste. What it doesn’t show is the breakdown of this debris by wind and tide into microplastics, now sickening people and animals. Image by Plastic Captain Darwin via Wikimedia Commons (CC BY-SA 4.0).
Banner: A black-winged stilt (Himantopus himantopus) forages in a swamp polluted with plastic and other trash. Image by Sham Prakash via Pexels (Public domain).
Editor’s Note: In 2015, a study developed nine indicators for planetary health, and corresponding nine threshold or boundaries. According to a recent study based on the same framework, six of the nine boundaries have already been crossed, while the other three are in the process of being crossed. This should come as a surprise to very few. The interesting fact about this new framework is that climate change is only one of the nine indicators in the new model, which is unlike in the mainstream environmental movement belief. This framework gives a much more holistic picture of the current ecological crisis than is common among the wider culture.
Scientists behind a new study on the crossing of the Earth’s “planetary boundaries” on Wednesday likened the planet to a sick patient, warning that six out of nine barriers that ensure the Earth is a “safe operating space for humanity” have now been breached.
Researchers at the University of Copenhagen, the Potsdam Institute for Climate Impact Research (PIK), and other international institutions analyzed 2,000 studies to update a planetary boundary framework developed in 2009 by the Stockholm Resilience Center, completing the first “complete check-up of all nine processes and systems that determine the stability and resilience of the planet.”
The boundaries for climate change and land use have been broken for decades as extractive industries have razed forests and planet-heating fossil fuel emissions have significantly increased since preindustrial times.
The “novel entities” boundary—pertaining to the accumulation of synthetic pollution from substances such as microplastics, pesticides, and nuclear waste—was quantified for the first time in the study, which was published in Science Advances.
Freshwater change—both “green” freshwater in soil and vegetation and “blue” freshwater in bodies of water—has also been breached, along with biogeochemical flows, or the flow of nitrogen and phosphorus into the environment, which can create ocean dead zones and algal blooms.
“We don’t know how long we can keep breaching these key boundaries before combined pressures lead to irreversible change and harm.”
The study marked the first time researchers quantified a control variable for the “biosphere integrity” boundary, which they found was breached long before the framework was introduced—in the late 19th century as the Industrial Revolution and other factors accelerated the destruction of the natural world.
Co-author Wolfgang Lucht called biosphere integrity “the second pillar of stability for our planet” next to climate change, and warned the pillar is being destabilized by humans “taking out too much biomass, destroying too much habitat, deforesting too much land. Our research shows that mitigating global warming and saving a functional biosphere for the future should go hand in hand.”
“This update on planetary boundaries clearly depicts a patient that is unwell, as pressure on the planet increases and vital boundaries are being transgressed,” said Johan Rockström, director of PIK. “We don’t know how long we can keep breaching these key boundaries before combined pressures lead to irreversible change and harm.”
The boundaries for atmospheric aerosol loading, or air pollution, and ocean acidification, are both close to being crossed, while the atmospheric ozone boundary is currently well below the “zone of increasing risk,” due to global initiatives within the Montreal Protocol, adopted in 1987.
The fact that the boundary for ozone depletion was once “headed for increasing regional transgressions” and slowly recovered, said co-author Katherine Richardson of the University of Copenhagen, shows that it is possible to bring the planet back from the boundaries that it’s close to crossing or that have been breached to a lesser degree, such as freshwater change.
“We can think of Earth as a human body, and the planetary boundaries as blood pressure,” said Richardson. “Over 120/80 does not indicate a certain heart attack but it does raise the risk and, therefore, we work to reduce blood pressure.”
The boundaries that have reached the highest risk level are biosphere integrity, climate change, novel entities, and biogeochemical flows.
The update to the framework “may serve as a renewed wake-up call to humankind that Earth is in danger of leaving its Holocene-like state,” reads the study, referring to relatively stable state the planet was in between the end of the last ice age—10,000 years ago—until the start of the Industrial Revolution.
The study, said global grassroots climate action campaign Extinction Rebellion, offered the latest evidence that policymakers must do everything in their power to “just stop oil”—ending approval for fossil fuel projects, subsidies for oil and gas companies, and policies that slow down a transition to renewable energy.
“We are not separate from the Earth,” said the group. “We ignore these warnings at our peril.”
Event alert: Planet Local Summit
Local futures is organizing its biggest and boldest event ever – the Planet Local Summit – which is set to begin this Friday! We are excited and honoured to welcome participants from 50 countries (and counting) to our livestream, along with our in-person audience in Bristol, UK.
If you haven’t already registered, there’s still time to book your attendance online and join like-minded localization community representatives from every corner of the earth.
In Bristol, the excitement is building, with a huge mural celebrating the Planet Local Summit unveiled in the city last week. Created by iconic local artists Silent Hobo and Inkie, the colorful 600 ft mural (pictured above) has been unveiled at the Tobacco Factory – Bristol’s biggest and most famous street art wall.
Local groups have also organized 10 pre-summit events to highlight the best of Bristol, including farm open days, community dialogues, and food tours.
Editor’s note: This article is an update from a year ago. Trying to fix the climate change planetary boundary at the expense of biodiversity or any of the other planetary boundaries is a fool’s errand. This article does not state the fact that it only takes one planetary boundary to collapse to cause a massive die-off of life on the planet. Plus no mention of the poly-crisis of nuclear war, increasing inequality, AI and global economic crash.
Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold;
Mere anarchy is loosed upon the world,
The blood-dimmed tide is loosed, and everywhere
The ceremony of innocence is drowned;
The best lack all conviction, while the worst
Are full of passionate intensity. – The Second Coming William Butler Yeats in 1919
By Edward Carver writer for Common Dreams
Six of nine planetary boundaries have already been transgressed, and a seventh, for ocean acidification, is on the verge of being breached, according to a major report released Monday.
The 96-page report, produced by the Potsdam Institute for Climate Impact Research (PIK), is the first in a planned series of annual “planetary health checks.”
The authors found that safe planetary boundaries had already been crossed for the climate, freshwater, land use, biogeochemical flows, novel entities, and biosphere integrity—in keeping with a study in Science Advances last year. They found a “clear trend towards further transgression”—moving deeper into the danger zone, where irreversible tipping points are more likely to be triggered—in each of the six categories.
“Our updated diagnosis shows that vital organs of the Earth system are weakening, leading to a loss of resilience and rising risks of crossing tipping points,” Levke Caesar, a PIK climate physicist lead author of the report, said in a statement that announced a “red alert.”
The health check also showed that ocean acidification, a seventh category, has reached a dangerous precipice, putting the foundations of the marine food web at risk. Ocean acidification, which can threaten coral reefs and phytoplankton populations, is caused by the buildup of carbon dioxide from burning fossil fuels and other human activities.
Caesar said a “safe operating space” threshold for acidification could be crossed in the next few years.
“Looking at the current evolution, I’d say it’s really, really difficult to prevent that [boundary] crossing,” she toldMongabay.
A graphic shows the status of nine environmental categories, four of which have been broken down into two control variables. Image from Planetary Health Check 2024. Design by Globaïa.
PIK director Johan Rockström, a co-author of the new report, helped develop planetary boundary research in the late 2000s. In a seminal 2009 paper in Nature, he and his co-authors found that three of the nine boundaries had already been crossed. That number has gradually gone up based on a series of studies over the last decade.
The planet boundary framework, which is often connected to the degrowth movement, emphasizes that the categories are interconnected.
“The interconnectedness of [planetary boundary] processes means that addressing one issue, such as limiting global warming to 1.5°C, requires tackling all of them collectively,” the new report says.
Boris Sakschewski, a climate scientist who, along with Caesar, is a lead author of the report said that, “We know that all planetary boundary processes act together and each one needs protection to protect the whole system.”
The consequences of continued ocean acidification, which is primarily measured by aragonite saturation, would be severe, the report warns.
Ocean acidification is approaching a critical threshold, with significant declines in surface aragonite saturation, particularly in high-latitude regions like the Arctic and Southern Ocean. These areas are vital for the marine carbon pump and global nutrient cycles, which support marine productivity, biodiversity, and global fisheries. The growing acidification poses an increasing threat to marine ecosystems, especially those reliant on calcium carbonate for shell formation.
Some researchers believe that the ocean acidification threshold has already been crossed, especially given regional variability, with cooler polar waters absorbing more carbon dioxide, causing a faster drop in pH levels.
The report was written with a general audience in mind and is not peer-reviewed, though it’s based on peer-reviewed studies, the authors said.
The final pages of the report present solutions, especially agricultural. A radical overhaul of the global food system, heavily dependent on fertilizer and other harmful inputs, will be necessary to reverse the disturbing trends documented in the report, the authors wrote.
“Sometimes overlooked compared to the impacts of energy production and consumption—particularly the use of fossil fuels—the food systems we depend on are among the largest drivers of environmental degradation. The global food system is the single largest driver behind the transgression of multiple planetary boundaries,” the report says.
Water seems deceptively simple and is easy to take for granted. It has no color, taste or smell and is one of the most plentiful chemical compounds on Earth. Recycled endlessly through the biosphere in its various forms, it is fundamental to keeping our planet’s operating system intact, and has done so for millions of years.
Water is life. Earth’s oceans are where life likely originated, and freshwater is essential for plants and animals to persist and thrive. It is basic to all human development. But as our 21st-century world gallops ahead, we are vastly manipulating the water cycle at an unprecedented rate and scale to meet the ever-growing needs of an exploding population.
By 2030, we will have built enough dams to alter 93% of the world’s rivers. Estimates vary, but we already use around 90% of the planet’s freshwater to grow our food. More than half of us now live in cities, but by 2050 a projected 68% of the world’s nearly 8 billion people will reside in urban areas. That metropolitan lifestyle will require astronomical amounts of water — extracted, treated, and piped over large distances. Humanity also prevents much rainwater from easily infiltrating underground, reducing aquifers, as we pave over immense areas with impermeable concrete and asphalt.
But these easily visible changes are only the proverbial tip of the iceberg. Researchers are shining new light on sweeping human alterations to Earth’s water cycle, many playing out in processes largely unseen. In the Anthropocene — the unofficial name for the current human-influenced unit of geologic time — we are already pushing one of Earth’s most fundamental and foundational systems, the hydrological cycle, toward the breaking point.
Trouble is, we don’t yet know when this threshold may be reached, or what the precise consequences will be. Scientists are resolutely seeking answers.
Water flows past Copenhagen in Denmark. As Earth’s urban areas expand, so do population pressures on the freshwater supply and the water cycle. Image by Petro Kotzé.
Water cycle basics
The hydrological cycle is powered by the sun and flows through eternal inhalations and exhalations of water in different states, as it is exchanged between the atmosphere and the planet. Liquid water from oceans, lakes and rivers rises via evaporation into the sky, to form water vapor, an important greenhouse gas that, like carbon dioxide, helps insulate the planet to maintain that “just right” temperature to maintain life as we know it.
Atmospheric water vapor then changes to liquid, falling to earth as precipitation. It then flows as runoff again across the landscape, and what doesn’t go back into waterbodies, settles into soils, to be taken up by plants and released via transpiration as vapor skyward. A large amount of freshwater is also locked in glaciers and icecaps.
Within this cycle, there are constant complex interactions between what scientists call blue and green water. Blue water includes rivers, lakes, reservoirs and renewable groundwater stores. Green water is defined as terrestrial precipitation, evaporation and soil moisture.
Partitioning of rainwater into green and blue water flows. Image by Geertsma et al. (2009)/Baseline Review for the Pilot Programme in Kenya. Green Water Credits Report 8, ISRIC–World Soil Information, Wageningen.
A fully functioning hydrological cycle, with balanced supplies and flows of blue and green water, is essential to terrestrial and aquatic ecosystems, human food availability and production, and our energy security.
It also regulates Earth’s weather and influences climate. Atmospheric temperature, for example, is dependent on evaporation and condensation. That’s because as water evaporates, it absorbs energy and cools the local environment, and as it condenses, it releases energy and warms the world. Throughout the Holocene geological epoch, a relatively stable water cycle helped maintain balanced temperatures and conditions able to support civilization.
However, in the Anthropocene, human activity has impacted the water cycle, the climate and ecosystems. For one, as more human-produced CO2 and methane build up in the atmosphere, more solar energy is held by the planet, causing global warming. And the hotter the air, the greater the quantity of water vapor the atmosphere can hold. That’s bad news because water vapor is itself a powerful greenhouse gas, greatly increasing the warming.
As our anthropogenic manipulation of the water cycle escalates on a global scale, we urgently need a holistic way to monitor these modifications and understand their impacts. Yet, the topic has not received the urgent scientific attention it requires. “To the best of our knowledge, there is no study comprehensively investigating whether human modifications of the water cycle have led, could be leading, or will lead to planetary‐scale regime shifts in the Earth system,” researchers noted in a 2020 paper on the role of the water cycle in maintaining fundamental Earth functioning.
One key concern of scientists: If severe hydrological shifts occur in too many regions, or in key regions that greatly influence the water cycle or water availability (such as the Amazon), then that could provoke shifts in other regions, in a global chain reaction, says study co-author Dieter Gerten, working group leader and Earth modeling coordinator at the Potsdam Institute for Climate Impact Research in Germany.
“Conceptually we know that there must be a limit for how much we can disturb the [hydrological] system before we start feeling serious impacts on the Earth system and then, by extension, to humanity,” says one of the paper’s other co-authors, Miina Porkka, a postdoctoral researcher at the Water and Development Group at Aalto University in Finland.
International researchers under the auspices of the Stockholm Resilience Centre have been hammering away at answering these questions. They had to start with the basics. One big problem to date has been scientists’ lack of a metric for quantifying serious water cycle alterations. How do we even measure changes to the water cycle?
“It gets complicated,” says Gerten, who has been involved in the research to bring a global perspective to local water management since 2009, as conducted under the Planetary Boundaries Framework; Gerten is also a professor of global change climatology and hydrology at Humboldt University of Berlin.
The Toktogul reservoir in Kyrgyzstan. The Anthropocene is producing wholesale manipulations to Earth’s water cycle. For example, by 2030, more than 90% of the world’s rivers will likely be altered by dams. Image by Petro Kotzé.
Measuring change: Blue water
The Planetary Boundaries Framework defines a safe operating space for humanity as represented by nine natural global processes that, if severely destabilized, could disrupt Earth’s operating system and threaten life and civilization. The freshwater planetary boundary presents one such threshold, and scientists are working to define a global limit to anthropogenic water cycle modifications.
Initially, in 2009, river flow was used to try and measure the boundary threshold, Gerten explains, because blue water in all its forms was seen to integrate the three largest anthropogenic manipulations of the water cycle: human impacts on precipitation patterns, modifications of soil moisture by land use and land cover; and water withdrawals for human use.
This research used a simple calculation of the global sum of the average annual surface water flow in rivers, with an assumed 30% of that accessible water needing to be protected. This “freshwater use” boundary was set at 4,000 cubic kilometers (960 cubic miles) per year of blue water consumption. This is at the lower limit of a 4,000-6,000 km3 (960-1,440 mi3) annual range designated as a danger zone that takes us “too close to the risk of blue and green water-induced thresholds that could have deleterious or even catastrophic impacts on the Earth System,” researchers wrote in a 2020 paper that evaluated the water planetary boundary.
The Padysha-Ata River in Kyrgyzstan. Blue water includes rivers as well as lakes, reservoirs, and renewable groundwater stores. Image by Petro Kotzé.
With only an estimated 2,600 km3 (624 mi3) of water withdrawn annually at the time of the study, scientists concluded we were still in the safe zone. However, “That [conclusion] was immediately criticized,” Gerten says, in part because scientists were already seeing ample regional water-related problems. Another criticism argued that the measure of blue water alone did not reflect all types of human interference with the water cycle and Earth system.
Gerten later led work that proposed quantifying the boundary by assessing the amount of streamflow needed to maintain environmental flow requirements in all river basins on Earth. This approach had the advantage of recognizing regionally transgressed limits and thereby deduced a global value.
According to this newer calculation, the freshwater use planetary boundary should be set much lower, at about 2,800 km3 (672 mi3), Gerten says, which means humanity is already much closer to the danger zone than previously thought. “Water is more limited on Planet Earth than we think,” Gerten cautions.
The nine planetary boundaries, counterclockwise from top: climate change, biosphere integrity (functional and genetic), land-system change, freshwater change, biogeochemical flows (nitrogen and phosphorus), ocean acidification, atmospheric aerosol pollution, stratospheric ozone depletion, and release of novel chemicals. In 2022, scientists announced the transgression of both the freshwater and novel entities boundaries. Image courtesy of J. Lokrantz/Azote based on Steffen et al. (2015) via Stockholm Resilience Centre.
Redefining the freshwater boundary: Green water
Over time, a consortium of researchers was formed to deeply scrutinize the freshwater boundary. This resulted in follow-up work in 2019 and 2020 proposing that the freshwater boundary be divided into sub-boundaries related to major stores of freshwater: namely atmospheric water, frozen water, groundwater, soil moisture, and surface water.
Since then, scientists simplified their approach further. “Even though we are talking about very complex matters,” Porkka says, the boundary definition, to be useful as a metric, needed to stay “relatively simple.”
The most recent and sweeping reassessment of the freshwater planetary boundary was published in 2022. “Our suggestion is to … change the name from ‘freshwater use planetary boundary’ to ‘freshwater change planetary boundary,’” says study lead author Lan Wang-Erlandsson from the Stockholm Resilience Centre. “Then, to have two components,” she adds, “One for green water, and one for blue water.”
“Water has so many functions in the Earth system, and many of them happen invisibly via green water,” Gerten explains. “We don’t see it and we don’t feel it. That’s why [green water] has been neglected over decades. The focus has been on river flows and groundwater because we can see it, feel it, use it, and touch it. But [as a result] a big share of the water cycle has been overlooked.”
The Tsitsikamma forests in South Africa’s Garden Route region. The water taken up by plants and released via transpiration as vapor skyward is an integral part of the water cycle. Image by Petro Kotzé.
The newly accepted metric for tracking green water: The soil moisture in the root zone of plants, or more technically: “the percentage of ice-free land area on which root-zone soil moisture anomalies exit the local bounds of baseline variability in any month of the year.”
This new proxy is appealing because it is directly influenced by human pressures with change over time measurable. In turn, soil moisture directly impacts a range of large-scale ecological, climatic, biogeochemical and hydrological dynamics.
Using this novel green water boundary transgression criteria, scientists detected a major hydrological departure from the baseline set during the Holocene. And the evidence for such a departure is overwhelming: Researchers found “unprecedented areas [of Earth] with root-zone soil moisture anomalies,” indicating an exit from the so-called “safe zone.”
A second criteria, Earth Systems Resilience, was also instituted. Researchers evaluated the state of regional climate systems (ranging from monsoons to land carbon sinks and large biomes) to see which have seen enhanced changes in their process rates, resulting in ripple effects that could destabilize the Earth system, Wang-Erlandsson explains.
Lake Sary-Chelek, part of a UNESCO Biosphere Reserve, in Kyrgyzstan. The hydrological cycle represents an eternal exchange of water in different states between the atmosphere and the planet’s surface, and it maintains the biosphere as we know it. Within this cycle, there is constant interaction between blue and green water. Image by Petro Kotzé.
A transgressed freshwater change boundary
Unfortunately, examples of compromised Earth System Resilience transgressions are rife across the planet.
Take the Amazon Rainforest, for instance. It is now understood that carbon uptake likely peaked there in the 1990s, with a sequestration decline since then driven by escalating climate change and fires, along with global demand for agricultural commodities, which spurred extensive Amazon forest clearing, bringing major land-use change. More recently, African tropical forests have passed their carbon uptake peak.
When these vast biomes and natural systems are put under extreme multiple stressors, the effects can self-amplify and lead to greater, more rapid, rates of change, Wang-Erlandsson says: In South America, this combination of stressors, particularly deforestation and climate change, is inducing intensifying drought, which is now leading to cascading perturbations in living systems. Scientists now think the rainforest biome, stable for thousands of years, is reaching a tipping point, and could quickly transition to seasonal forest, or even a degraded savanna. This shift could lead to the transformation of the South American monsoon system, and a permanent state of reduced rainfall and impoverished biodiversity.
But what starts in the Amazon won’t likely stay there: The rainforest’s destruction will release massive amounts of carbon, intensifying climate change, potentially leading to climate and ecological tipping points in other biomes.
Agricultural development in Uzbekistan. Global land-use change, including large-scale deforestation and irrigation, is contributing to major alterations in the water cycle, leading to a destabilized climate and major global environmental and sociopolitical disruptions. Image by Petro Kotzé.
Another concerning example (although debated) of an Earth system shift is the suggestion of a weakening carbon fertilization process, in which higher atmospheric carbon concentrations result in speeded-up photosynthesis as plants try to improve water efficiency in the face of drought. It is thought that this effect is happening already, brought on by limitations in nutrient and soil moisture availability.
In drylands, climate change and ecosystem degradation are triggering vicious cycles of infiltration capacity loss — a decrease in soil moisture and moisture recycling, resulting in increasing desertification and biodiversity loss. In polar permafrost regions, soil moisture saturation could accelerate thawing, generating dangerous methane emissions. Methane is a greenhouse gas far more powerful than carbon dioxide.
Alarmed by the water cycle’s departure from the Holocene baseline, and noting “worrying” signs of low Earth System Resilience, researchers early in 2022 declared the green water boundary to be “considerably transgressed.” The situation, they said, will likely worsen before any reversals in the trend will be observed. “Green water modifications are now causing rising Earth system risks at a scale that modern civilizations might not have ever faced,” the study states.
We don’t yet know what the planetary-scale impacts will ultimately be, but, Porkka says, we have an idea of how impacts could be felt in different parts of the world.
An irrigation canal runs past apricot orchards in the Batken region of Kyrgyzstan. We have vastly manipulated Earth’s water cycle to suit humanity’s needs. Image by Petro Kotzé.
Disastrous extreme weather events
Regional extreme events, including floods and mega droughts, are already occurring, Porkka notes. Examples are to be found on every continent.
On Africa’s southeast coast, as just one example: the World Weather Attribution (WWA) network of scientists has found that human-induced climate change has increased the likelihood and intensity of heavy rainfall associated with tropical cyclones. The group based their findings on an analysis of tropical storms Ana and Batisrai, which battered parts of Madagascar, Mozambique, Malawi and Zimbabwe in early 2022. Both cyclonic systems brought devastating floods that caused severe humanitarian impacts, including many deaths and injuries and large-scale damage to infrastructure. These sorts of extreme weather events put great pressure on socioeconomic and political institutions, and could easily destabilize struggling developing nations.
Of the top 10 climate disasters, those causing the largest human losses during that period were droughts (650,000 deaths), storms (577,232), floods (58,700), and extreme temperature (55,736 deaths). In economic terms, the top 10 events included storms (costing $521 billion) and floods ($115 billion).
Clouds above a dusty road in the Northern Cape of South Africa. The hydrological cycle is powered by the sun and is an eternal exchange of water between the atmosphere and the planet. As climate change escalates, so do extreme weather events such as droughts and intense storms. Image by Petro Kotzé.
Porkka points out, however, that freshwater system destabilization impacts can be more subtle than extreme events. Widespread irrigation of croplands, for example, can increase evaporation to such a high degree that even distant precipitation patterns are altered. Part of the problem is that we do not know if consequences like these are negative or positive.
“[W]e know that we’re changing the [hydrological] system in fundamental ways and, once we do, we don’t really know how the impacts accumulate,” says Porkka.
While many riddles remain, scientists now feel they have a reliable metric for accurately tracking transgressions of the freshwater change boundary. “The prime question was what the key variables are, and I think that is relatively solid now with soil moisture [green water] and river flows [blue water],” Gerten says. “The next questions are, where exactly to put the boundaries, and what happens if they are transgressed?”
Based on these findings, researchers are calling for urgent action: “The current global trends and trajectories of increasing water use, deforestation, land degradation, soil erosion, atmospheric pollution, and climate change need to be promptly halted and reversed to increase the chances of remaining in [Earth’s] safe operating space.”
That’s a tall order, and no matter humanity’s actions, we don’t know how things will play out. “Water is so fundamental and elemental, and at the same time, so varied,” Gerten says, and there is no silver bullet for solving our hydrological problems.
South Africa’s Orange River tumbles over Augrabies Falls. Water is one of the most plentiful chemical compounds on Earth and is recycled endlessly through the biosphere in different forms. Image by Petro Kotzé.
Banner image: Farmers tending to their agricultural land in Uzbekistan. Image by Petro Kotzé.
Citations:
Scanlon, B. R., Jolly, I., Sophocleous, M., & Zhang, L. (2007). Global impacts of conversions from natural to agricultural ecosystems on water resources: Quantity versus quality. Water Resources Research, 43(3). doi:10.1029/2006wr005486
Gleeson, T., Wang‐Erlandsson, L., Porkka, M., Zipper, S. C., Jaramillo, F., Gerten, D., … Famiglietti, J. S. (2020). Illuminating water cycle modifications and earth system resilience in the Anthropocene. Water Resources Research, 56(4). doi:10.1029/2019wr024957
Gleeson, T., Wang-Erlandsson, L., Zipper, S. C., Porkka, M., Jaramillo, F., Gerten, D., … Famiglietti, J. S. (2020). The water planetary boundary: Interrogation and revision. One Earth, 2(3), 223-234. doi:10.1016/j.oneear.2020.02.009
Gerten, D., Hoff, H., Rockström, J., Jägermeyr, J., Kummu, M., & Pastor, A. V. (2013). Towards a revised planetary boundary for consumptive freshwater use: Role of environmental flow requirements. Current Opinion in Environmental Sustainability, 5(6), 551-558. doi:10.1016/j.cosust.2013.11.001
Zipper, S. C., Jaramillo, F., Wang‐Erlandsson, L., Cornell, S. E., Gleeson, T., Porkka, M., … Gordon, L. (2020). Integrating the water planetary boundary with water management from local to global scales. Earth’s Future, 8(2). doi:10.1029/2019ef001377
Wang-Erlandsson, L., Tobian, A., van der Ent, R. J., Fetzer, I., te Wierik, S., Porkka, M., … Rockström, J. (2022). A planetary boundary for green water. Nature Reviews Earth & Environment. doi:10.1038/s43017-022-00287-8
Hubau, W., Lewis, S. L., Phillips, O. L., Affum-Baffoe, K., Beeckman, H., Cuní-Sanchez, A., … Zemagho, L. (2020). Asynchronous carbon sink saturation in African and Amazonian tropical forests. Nature, 579(7797), 80-87. doi:10.1038/s41586-020-2035-0
Wang, S., Zhang, Y., Ju, W., Chen, J. M., Ciais, P., Cescatti, A., … Peñuelas, J. (2020). Recent global decline of CO2 fertilization effects on vegetation photosynthesis. Science, 370(6522), 1295-1300. doi:10.1126/science.abb7772
Ravi, S., Breshears, D. D., Huxman, T. E., & D’Odorico, P. (2010). Land degradation in drylands: Interactions among hydrologic-aeolian erosion and vegetation dynamics. Geomorphology, 116(3-4), 236-245. doi:10.1016/j.geomorph.2009.11.023
Van Luijk, G., Cowling, R. M., Riksen, M. J. P. M., & Glenday, J. (2013). Hydrological implications of desertification: Degradation of South African semi-arid subtropical thicket. Journal of Arid Environments, 91, 14-21. doi:10.1016/j.jaridenv.2012.10.022
Knoblauch, C., Beer, C., Liebner, S., Grigoriev, M. N., & Pfeiffer, E. (2018). Methane production as key to the greenhouse gas budget of thawing permafrost. Nature Climate Change, 8(4), 309-312. doi:10.1038/s41558-018-0095-z
You may not have noticed, but earlier this month we passed Earth overshoot day, when humanity’s demands for ecological resources and services exceeded what our planet can regenerate annually.
Many economists criticising the developing degrowth movement fail to appreciate this critical point of Earth’s biophysical limits.
Ecologists on the other hand see the human economy as a subset of the biosphere. Their perspective highlights the urgency with which we need to reduce our demands on the biosphere to avoid a disastrous ecological collapse, with consequences for us and all other species.
July 24, 2025 is Earth Overshoot Day, the baseline for the Earth’s resources we can sustainably use. First described in 1971 the overshoot day was Dec 25th. After that date we will be in ecological debt, humanity’s demand for nature’s resources will be exceeding the Earth’s capacity to regenerate
Many degrowth scholars (as well as critics) focus on features of capitalism as the cause of this ecological overshoot. But while capitalism may be problematic, many civilisations destroyed ecosystems to the point of collapse long before it became our dominant economic model.
Capitalism, powered by the availability of cheap and abundant fossil energy, has indeed resulted in unprecedented and global biosphere disruption. But the direct cause remains the excessive volume and speed with which resources are extracted and wastes returned to the environment.
From an ecologist’s perspective, degrowth is inevitable on our current trajectory.
Carrying capacity
Ecology tells us that many species overshoot their environment’s carrying capacity if they have temporary access to an unusually high level of resources. Overshoot declines when those resources return to more stable levels. This often involves large-scale starvation and die-offs as populations adjust.
Access to fossil fuels has allowed us to temporarily overshoot biophysical limits. This lifted our population and demands on the biosphere past the level it can safely absorb. Barring a planned reduction of those biosphere demands, we will experience the same “adjustments” as other species.
One advantage humans have over other species is that we understand overshoot dynamics and can plan how we adjust. This is what the degrowth movement is attempting to do.
To grasp the necessity of reducing ecological overshoot we must understand its current status. We can do this by examining a variety of empirical studies.
Material flows and planetary boundaries
Analysis of material flows in the economy shows we are currently extracting more than 100 billion tons of natural materials annually, and rising. This greatly exceeds natural processes – erosion, volcanic eruptions and earthquakes – that move materials around the globe.
Only about 10% of these resource flows are potentially renewable. In many cases, we are harvesting more than can be regenerated annually (for example, many fish stocks).
Humans have now transgressed at least six of nine planetary boundaries. Each boundary has distinct limits, but in some instances the overshoot is at least double the safe operating level.
We have now exceeded six planetary boundaries, and for some by at least double the safe operating level. Stockholm Resilience Centre, CC BY-SA
Both material flow analysis and planetary boundaries provide critically important information about our impacts on the biosphere. But they fail to capture the full picture. The former doesn’t directly measure biosphere functioning. The latter doesn’t capture inter-dependencies between various boundaries.
The biosphere is a holistic entity, with many self-organising and interconnected subsystems. Our generally reductionist scientific methodologies are not able to capture this level of complexity. The methodology that comes closest to achieving this is the ecological footprint.
Biocapacity
The ecological footprint measures the amount of productive surface on Earth and its capacity to generate resources and assimilate waste. These are two of the most fundamental features of the biosphere.
It then compares this available biocapacity with humanity’s annual demands. Humanity’s ecological footprint has exceeded the biosphere’s annual biocapacity since at least 1970 and is currently almost twice the sustainable level.
The reason we can use more of what is generated annually is because we use stored biomass – ancient solar energy captured over millennia – to power this draw-down.
“The global economy will inevitably contract and humanity will suffer a major population ‘correction’ in this century.” New paper by Bill Rees (one of the people who conceptualized the idea of “the ecological footprint” just dropped…)
The political and public concern about climate change is considerable internationally and in New Zealand. But this is one of many environmental crises, together with soil erosion, groundwater pollution, deforestation, the rise of invasive species, biodiversity loss, ocean acidification and the depletion of resources. They are all symptoms of overshoot.
The climate crisis is seen as a problem requiring a solution rather than a symptom of overshoot. The problem is generally formulated as looking for a way to maintain current lifestyles in the wealthy world, rather than reducing overshoot.
The ecological perspective accepts that we exceed biophysical boundaries and emphasises the importance of reducing energy and material consumption – regardless of how the energy is provided.
The scope of human disruption of the biosphere is now global. This ecological perspective highlights the current magnitude and closeness of significant and unwelcome changes to Earth systems. The reduction of humanity’s demands on the biosphere is an overriding priority.
