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Planetary boundaries is a concept highlighting human-caused perturbations of Earth systems making them relevant in a way not accommodated by the environmental boundaries separating the three ages within the
Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
epoch. Crossing a planetary boundary comes at the risk of abrupt environmental change. The framework is based on scientific evidence that human actions, especially those of industrialized societies since the
Industrial Revolution The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
, have become the main driver of global environmental change. According to the framework, "transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental-scale to planetary-scale systems." The normative component of the framework is that human societies have been able to thrive under the comparatively stable climatic and ecological conditions of the
Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
. To the extent that these Earth system process boundaries have not been crossed, they mark the “safe zone” for human societies on the planet. The concept has since become influential in the international community (e.g. United Nations Conference on Sustainable Development), including governments at all levels, international organizations, civil society and the scientific community. The framework consists of nine global change processes. In 2009, according to Rockström and others, two boundaries were already crossed, while others were in imminent danger of being crossed. In 2015, several of the scientists in the original group published an update, bringing in new co-authors and new model-based analysis. According to this update, four of the boundaries were crossed: climate change, loss of biosphere integrity, land-system change, altered biogeochemical cycles (phosphorus and nitrogen). The scientists also changed the name of the boundary " Loss of biodiversity" to "Change in biosphere integrity" to emphasize that not only the number of species but also the functioning of the biosphere as a whole is important for Earth system stability. Similarly, the "Chemical pollution" boundary was renamed to "Introduction of novel entities," widening the scope to consider different kinds of human-generated materials that disrupt Earth system processes. In 2022, based on available literature, the introduction of novel entities was concluded to be the 5th transgressed planetary boundary.


Framework overview and principles

The basic idea of the Planetary Boundaries framework is that maintaining the observed resilience of the Earth system in the
Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
is a precondition for humanity’s pursuit of long-term social and economic development. The Planetary Boundaries framework contributes to an understanding of global
sustainability Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livi ...
because it brings a planetary scale and a long timeframe into focus. The framework described nine "planetary life support systems" essential for maintaining a “desired
Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
state”, and attempted to quantify how far seven of these systems had been pushed already. Boundaries were defined to help define a "safe space for human development", which was an improvement on approaches aiming at minimizing human impacts on the planet. The framework is based on scientific evidence that human actions, especially those of industrialized societies since the
Industrial Revolution The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
, have become the main driver of global environmental change. According to the framework, "transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental-scale to planetary-scale systems." The framework consists of nine global change processes. In 2009, two boundaries were already crossed, while others were in imminent danger of being crossed. Later estimates indicated that three of these boundaries—
climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
,
biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic ('' genetic variability''), species ('' species diversity''), and ecosystem ('' ecosystem diversity'') ...
loss, and the biogeochemical flow boundary—appear to have been crossed. The scientists outlined how breaching the boundaries increases the threat of functional disruption, even collapse, in Earth’s biophysical systems in ways that could be catastrophic for human wellbeing. While they highlighted scientific uncertainty, they indicated that breaching boundaries could “trigger feedbacks that may result in crossing thresholds that drastically reduce the ability to return within safe levels”. The boundaries were "rough, first estimates only, surrounded by large uncertainties and knowledge gaps" which interact in complex ways that are not yet well understood. The planetary boundaries framework lays the groundwork for a shifting approach to governance and management, away from the essentially sectoral analyses of limits to growth aimed at minimizing negative
externalities In economics, an externality or external cost is an indirect cost or benefit to an uninvolved third party that arises as an effect of another party's (or parties') activity. Externalities can be considered as unpriced goods involved in either c ...
, toward the estimation of the safe space for human development. Planetary boundaries demarcate, as it were, the "planetary playing field" for humanity if major human-induced environmental change on a global scale is to be avoided.


Authors

The authors of this framework was a group of Earth System and environmental scientists in 2009 led by Johan Rockström from the
Stockholm Resilience Centre The Stockholm Resilience Centre (SRC), is a research centre on resilience and sustainability science at Stockholm University. It is a joint initiative between Stockholm University and the Beijer Institute of Ecological Economics at the Royal Swe ...
and Will Steffen from the
Australian National University The Australian National University (ANU) is a public research university located in Canberra, the capital of Australia. Its main campus in Acton encompasses seven teaching and research colleges, in addition to several national academies an ...
. They collaborated with 26 leading academics, including
Nobel Nobel often refers to: *Nobel Prize, awarded annually since 1901, from the bequest of Swedish inventor Alfred Nobel Nobel may also refer to: Companies *AkzoNobel, the result of the merger between Akzo and Nobel Industries in 1994 *Branobel, or ...
laureate
Paul Crutzen Paul Jozef Crutzen (; 3 December 1933 – 28 January 2021) was a Dutch meteorologist and atmospheric chemist. He was awarded the Nobel Prize in Chemistry in 1995 for his work on atmospheric chemistry and specifically for his efforts in studyin ...
,
Goddard Institute for Space Studies The Goddard Institute for Space Studies (GISS) is a laboratory in the Earth Sciences Division of NASA's Goddard Space Flight Center affiliated with the Columbia University Earth Institute. The institute is located at Columbia University in ...
climate scientist
James Hansen James Edward Hansen (born March 29, 1942) is an American adjunct professor directing the Program on Climate Science, Awareness and Solutions of the Earth Institute at Columbia University. He is best known for his research in climatology, his ...
, oceanographer Katherine Richardson, geographer Diana Liverman and the
German Chancellor The chancellor of Germany, officially the federal chancellor of the Federal Republic of Germany,; often shortened to ''Bundeskanzler''/''Bundeskanzlerin'', / is the head of the federal government of Germany and the commander in chief of the Ge ...
's chief climate adviser Hans Joachim Schellnhuber. Most of the contributing scientists were involved in strategy-setting for the Earth System Science Partnership, the precursor to the international global change research network Future Earth. The group wanted to define a "safe operating space for humanity" for the wider scientific community, as a precondition for
sustainable development Sustainable development is an organizing principle for meeting human development goals while also sustaining the ability of natural systems to provide the natural resources and ecosystem services on which the economy and society depend. The ...
.


Nine boundaries


Thresholds and tipping points

The 2009 study identified nine planetary boundaries and, drawing on current scientific understanding, the researchers proposed quantifications for seven of them. These are: # climate change ( CO2 concentration in the atmosphere < 350 ppm and/or a maximum change of +1 W/m2 in
radiative forcing Radiative forcing (or climate forcing) is the change in energy flux in the atmosphere caused by natural or anthropogenic factors of climate change as measured by watts / metre2. It is a scientific concept used to quantify and compare the extern ...
); #
ocean acidification Ocean acidification is the reduction in the pH value of the Earth’s ocean. Between 1751 and 2021, the average pH value of the ocean surface has decreased from approximately 8.25 to 8.14. The root cause of ocean acidification is carbon dioxid ...
(mean surface seawater saturation state with respect to aragonite ≥ 80% of pre- industrial levels); #
stratospheric The stratosphere () is the second layer of the atmosphere of the Earth, located above the troposphere and below the mesosphere. The stratosphere is an atmospheric layer composed of stratified temperature layers, with the warm layers of air h ...
ozone depletion (less than 5% reduction in total atmospheric O3 from a pre-industrial level of 290 Dobson Units); # biogeochemical flows in the nitrogen (N) cycle (limit industrial and agricultural fixation of N2 to 35 Tg N/yr) and phosphorus (P) cycle (annual P inflow to oceans not to exceed 10 times the natural background
weathering Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs '' in situ'' (on site, with little or no movement ...
of P); # global freshwater use (< 4000 km3/yr of consumptive use of runoff resources); # land system change (< 15% of the ice-free land surface under cropland); # the erosion of biosphere integrity (an annual rate of loss of biological diversity of < 10 extinctions per million species). # chemical pollution (introduction of novel entities in the environment). For one process in the planetary boundaries framework, the scientists have not specified a global boundary quantification:
  1. atmospheric aerosol loading;
The quantification of individual planetary boundaries is based on the observed dynamics of the interacting Earth system processes included in the framework. The control variables were chosen because together they provide an effective way to track the human-caused shift away from Holocene conditions. For some of Earth’s dynamic processes, historic data display clear thresholds between comparatively stable conditions. For example, past ice-ages show that during peak glacial conditions, the atmospheric concentration of CO2 was ~180-200 ppm. In interglacial periods (including the Holocene), CO2 concentration has fluctuated around 280 ppm. To know what past climate conditions were like with an atmosphere with over 350 ppm CO2, scientists need to look back about 3 million years. The paleo record of climatic, ecological and biogeochemical changes shows that the Earth system has experienced tipping points, when a very small increment for a control variable (like CO2) triggers a larger, possibly catastrophic, change in the response variable (global warming) through feedbacks in the natural Earth System itself. For several of the processes in the planetary boundaries framework, it is difficult to locate individual points that mark the threshold shift away from Holocene-like conditions. This is because the Earth system is complex and the scientific evidence base is still partial and fragmented. Instead, the planetary boundaries framework identifies many Earth system thresholds at multiple scales that will be influenced by increases in the control variables. Examples include shifts in
monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscil ...
behavior linked to the aerosol loading and freshwater use planetary boundaries.


"Safe operating spaces"

The planetary boundaries framework proposes a range of values for its control variables. This range is supposed to span the threshold between a 'safe operating space' where Holocene-like dynamics can be maintained and a highly uncertain, poorly predictable world where Earth system changes likely increase risks to societies. The ''boundary'' is defined as the lower end of that range. If the boundaries are persistently crossed, the world goes further into a danger zone. It is difficult to restore a 'safe operating space' for humanity that is described by the planetary boundary concept. Even if past biophysical changes could be mitigated, the predominant paradigms of social and economic development appear largely indifferent to the looming possibilities of large scale environmental disasters triggered by human actions. Legal boundaries can help keep human activities in check, but are only as effective as the political will to make and enforce them.


Interaction among boundaries

Understanding the Earth system is fundamentally about understanding interactions among environmental change processes. The planetary boundaries are defined with reference to dynamic conditions of the Earth system, but scientific discussions about how different planetary boundaries relate to each other are often philosophically and analytically muddled. Clearer definitions of the basic concepts and terms might help give clarity. There are many many interactions among the processes in planetary boundaries the framework. While these interactions can create both stabilizing and destabilizing feedbacks in the Earth system, the authors suggested that a transgressed planetary boundary will reduce the safe operating space for other processes in the framework rather than expand it from the proposed boundary levels. They give the example that the
land use Land use involves the management and modification of natural environment or wilderness into built environment such as settlements and semi-natural habitats such as arable fields, pastures, and managed woods. Land use by humans has a long ...
boundary could “shift downward” if the freshwater boundary is breached, causing lands to become arid and unavailable for agriculture. At a regional level, water resources may decline in Asia if
deforestation Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated ...
continues in the
Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technolog ...
. That way of framing the interactions shifts from the framework’s biophysical definition of boundaries based on Holocene-like conditions to an anthropocentric definition (demand for agricultural land). Despite this conceptual slippage, considerations of known Earth system interactions across scales suggest the need for "extreme caution in approaching or transgressing any individual planetary boundaries." Another example has to do with
coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...
s and marine ecosystems: In 2009, researchers showed that, since 1990, calcification in the reefs of the Great Barrier that they examined decreased at a rate unprecedented over the last 400 years (14% in less than 20 years). Their evidence suggests that the increasing temperature stress and the declining ocean saturation state of aragonite is making it difficult for reef corals to deposit calcium carbonate. Multiple stressors, such as increased nutrient loads and fishing pressure, moves corals into less desirable ecosystem states. Ocean acidification will significantly change the distribution and abundance of a whole range of marine life, particularly species "that build skeletons, shells, and tests of biogenic calcium carbonate. Increasing temperatures, surface
UV radiation Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiatio ...
levels and ocean acidity all stress marine biota, and the combination of these stresses may well cause perturbations in the abundance and diversity of marine biological systems that go well beyond the effects of a single stressor acting alone."


Proposed new or expanded boundaries since 2012

In 2012, Steven Running suggested a tenth boundary, the annual net global
primary production In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. It principally occurs through the process of photosynthesis, which uses light as its source of energy, but it also occurs through ...
of all
terrestrial plant A terrestrial plant is a plant that grows on, in, or from land. Other types of plants are aquatic (living in water), epiphytic (living on trees) and lithophytic (living in or on rocks). The distinction between aquatic and terrestrial plants i ...
s, as an easily determinable measure integrating many variables that will give "a clear signal about the health of ecosystems". In 2015, a second paper was published in ''
Science Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence ...
'' to update the Planetary Boundaries concept. The update concluded four boundaries had now been transgressed: climate, biodiversity, land use and biogeochemical cycles. The 2015 paper emphasized interactions of the nine boundaries and identified climate change and loss of biodiversity integrity as ‘core boundaries’ of central importance to the framework because the interactions of climate and the biosphere are what scientifically defines Earth system conditions. In 2017, some authors argued that marine systems are underrepresented in the framework. Their proposed remedy was to include the
seabed The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most o ...
as a component of the earth surface change boundary. They also wrote that the framework should account for "changes in vertical mixing and ocean circulation patterns". Subsequent work on planetary boundaries begins to relate these thresholds at the regional scale.


Debate and further research per boundary


Climate change

A 2018 study calls into question the adequacy of efforts to limit warming to 2 degrees above pre-industrial temperatures, as set out in the
Paris Agreement The Paris Agreement (french: Accord de Paris), often referred to as the Paris Accords or the Paris Climate Accords, is an international treaty on climate change. Adopted in 2015, the agreement covers climate change mitigation, adaptation, and ...
. The scientists raise the possibility that even if
greenhouse gas emissions Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and ...
are substantially reduced to limit warming to 2 degrees, that might exceed the "threshold" at which self-reinforcing climate feedbacks add additional warming until the climate system stabilizes in a hothouse climate state. This would make parts of the world uninhabitable for people, raise sea levels by up to 60 metres (200 ft), and raise temperatures by 4–5 °C (7.2–9.0 °F) to levels that are higher than any
interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...
period in the past 1.2 million years.


Change in biosphere integrity

According to the biologist Cristián Samper, a "boundary that expresses the probability of families of species disappearing over time would better reflect our potential impacts on the future of life on Earth." The biodiversity boundary has also been criticized for framing biodiversity solely in terms of the extinction rate. The global extinction rate has been highly variable over the Earth's history, and thus using it as the only biodiversity variable can be of limited usefulness.


Nitrogen and phosphorus

The biogeochemist William Schlesinger thinks waiting until we near some suggested limit for nitrogen deposition and other pollutions will just permit us to continue to a point where it is too late. He says the boundary suggested for phosphorus is not sustainable, and would exhaust the known phosphorus reserves in less than 200 years. The ocean chemist Peter Brewer queries whether it is "truly useful to create a list of environmental limits without serious plans for how they may be achieved ... they may become just another stick to beat citizens with. Disruption of the global nitrogen cycle is one clear example: it is likely that a large fraction of people on Earth would not be alive today without the artificial production of fertilizer. How can such ethical and economic issues be matched with a simple call to set limits? ... food is not optional.".
Peak phosphorus Peak phosphorus is a concept to describe the point in time when humanity reaches the maximum global production rate of phosphorus as an industrial and commercial raw material. The term is used in an equivalent way to the better-known term peak ...
is a concept to describe the point in time at which the maximum global
phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ea ...
production rate is reached. Phosphorus is a scarce finite resource on earth and means of production other than mining are unavailable because of its non-gaseous environmental cycle. According to some researchers, Earth's phosphorus reserves are expected to be completely depleted in 50–100 years and peak phosphorus to be reached by approximately 2030.


Ocean acidification

Surface ocean acidity is clearly interconnected with the climate change boundaries, since the concentration of carbon dioxide in the atmosphere is also the underlying control variable for the ocean acidification boundary. The ocean chemist Peter Brewer thinks "ocean acidification has impacts other than simple changes in pH, and these may need boundaries too."


Land-system change

Across the planet, forests, wetlands and other vegetation types are being converted to agricultural and other
land use Land use involves the management and modification of natural environment or wilderness into built environment such as settlements and semi-natural habitats such as arable fields, pastures, and managed woods. Land use by humans has a long ...
s, impacting freshwater, carbon and other cycles, and reducing biodiversity. In the year 2015 the boundary was defined as 75% of
forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...
s rested intact, including 85% of boreal forests, 50% of
temperate forest A temperate forest is a forest found between the tropical and boreal regions, located in the temperate zone. It is the second largest biome on our planet, covering 25% of the world's forest area, only behind the boreal forest, which covers abou ...
s and 85% of
tropical forest Tropical forests (a.k.a. jungle) are forested landscapes in tropical regions: ''i.e.'' land areas approximately bounded by the tropic of Cancer and Capricorn, but possibly affected by other factors such as prevailing winds. Some tropical fore ...
s. The boundary is crossed because only 62% of forests rested intact as of the year 2015. The boundary for land use has been criticized as follows: "The boundary of 15 per cent land-use change is, in practice, a premature policy guideline that dilutes the authors' overall scientific proposition. Instead, the authors might want to consider a limit on soil degradation or soil loss. This would be a more valid and useful indicator of the state of terrestrial health."


Freshwater

The freshwater cycle is another boundary significantly affected by climate change.
Overexploitation Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term ap ...
of freshwater occurs if a water resource is mined or extracted at a rate that exceeds the recharge rate.
Water pollution Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. ...
and saltwater intrusion can also turn much of the world's underground water and lakes into finite resources with " peak water" usage debates similar to oil.. The hydrologist David Molden stated in 2009 that planetary boundaries are a welcome new approach in the " limits to growth" debate but said "a global limit on water consumption is necessary, but the suggested planetary boundary of 4,000 cubic kilometres per year is too generous.".


= Green and blue water

= A study concludes that the 'Freshwater use' boundary should be renamed to the 'Freshwater change', composed of "green" and "blue" water components. 'Green water' refers to disturbances of terrestrial precipitation, evaporation and soil moisture.
Water scarcity Water scarcity (closely related to water stress or water crisis) is the lack of fresh water resources to meet the standard water demand. There are two types of water scarcity: physical or economic water scarcity. Physical water scarcity is whe ...
can have substantial effects in agriculture. When measuring and projecting water scarcity in
agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people ...
for climate change scenarios, both "green water" and "blue water" are of relevance. In April 2022, scientists proposed and preliminarily evaluated 'green water' in the
water cycle The water cycle, also known as the hydrologic cycle or the hydrological cycle, is a biogeochemical cycle that describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly co ...
as a likely transgressed planetary boundary, as measured by root-zone soil moisture deviation from Holocene variability.


Ozone depletion

The stratospheric
ozone layer The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in rel ...
protectively filters ultraviolet radiation (UV) from the Sun, which would otherwise damage biological systems. The actions taken after the
Montreal Protocol The Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion. It was agreed on 16 September 1987, and entered into force ...
appeared to be keeping the planet within a safe boundary. The Nobel laureate in chemistry, Mario Molina, says "five per cent is a reasonable limit for acceptable ozone depletion, but it doesn't represent a tipping point".


Atmospheric aerosols

Worldwide each year,
aerosol An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of anthropogen ...
particles result in about 800,000 premature deaths from
air pollution Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different type ...
. Aerosol loading is sufficiently important to be included among the planetary boundaries, but it is not yet clear whether an appropriate safe threshold measure can be identified.


Novel entities (chemical pollution)

Some chemicals, such as persistent organic pollutants, heavy metals and
radionuclide A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transfer ...
s, have potentially irreversible additive and synergic effects on biological organisms, reducing fertility and resulting in permanent genetic damage. Sublethal uptakes are drastically reducing marine bird and mammal populations. This boundary seems important, although it is hard to quantify. In 2019, it was suggested that novel entities could include
genetically modified organism A genetically modified organism (GMO) is any organism whose genetic material has been altered using genetic engineering techniques. The exact definition of a genetically modified organism and what constitutes genetic engineering varies, wit ...
s,
pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and ...
s and even
artificial intelligence Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech ...
. A Bayesian emulator for persistent organic pollutants has been developed which can potentially be used to quantify the boundaries for chemical pollution. To date, critical exposure levels of polychlorinated biphenyls (PCBs) above which mass mortality events of marine mammals are likely to occur, have been proposed as a chemical pollution planetary boundary. There are at least 350,000 artificial chemicals in the world. They are coming from "
plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adapta ...
s,
pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and ...
s, industrial chemicals, chemicals in consumer products,
antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...
s and other
pharmaceuticals A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field and re ...
". They have mostly "negative effects on planetary health". Their production increased 50 times since 1950 and expected to increase 3 times more by 2050. Plastic alone contain more than 10,000 chemicals and create large problems. The researchers are calling for limit on chemical production and shift to
circular economy A circular economy (also referred to as circularity and CE) is a model of production and consumption, which involves sharing, leasing, reusing, repairing, refurbishing and recycling existing materials and products as long as possible. CE aim ...
, meaning to products that can be
reuse Reuse is the action or practice of using an item, whether for its original purpose (conventional reuse) or to fulfill a different function ( creative reuse or repurposing). It should be distinguished from recycling, which is the breaking down of u ...
d and
recycled Recycling is the process of converting waste materials into new materials and objects. The recovery of energy from waste materials is often included in this concept. The recyclability of a material depends on its ability to reacquire the p ...
. In January 2022 a group of scientists concluded that this planetary boundary is already exceeded, which puts in risk the stability of the Earth system. They integrated the literature information on how production and release of a number of novel entities, including
plastics Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptabi ...
and hazardous chemicals, have rapidly increased in the last decades with significant impact on the planetary processes. In August 2022, scientists concluded that the (overall transgressed) boundary is a placeholder for multiple different boundaries for NEs that may emerge, reporting that PFAS pollution is one such new boundary. They show that levels of these so-called " forever chemicals" in rainwater are ubiquitously, and often greatly, above guideline safe levels worldwide. There are some moves to restrict and replace their use.


Related concepts


Planetary integrity

Planetary integrity, also called "earth’s life-support systems" or "ecological integrity", needs to be maintained for long-term
sustainability Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livi ...
. Text was copied from this source, which is available under
Creative Commons Attribution 4.0 International License
/ref> The notion of planetary integrity derives from its root term "ecological integrity", which was initially developed to describe the declining state of biodiversity on a sub-global scale. In this context, "integrity" is a way of thinking about ecological health affected by human activities. The concept of planetary integrity is becoming popular at several levels of analysis. It is, for example, implied in the notion of planetary boundaries. An expert Panel on Ecological Integrity in 1998 has defined ecological integrity as follows: "An ecosystem has integrity when it is deemed characteristic for its natural region, including the composition and abundance of native species and biological communities, rates of change and supporting processes. In plain language, ecosystems have integrity when they have their native components (plants, animals and other organisms) and processes (such as growth and reproduction) intact.". There now seems to be general agreement that planetary integrity is being impacted in unprecedented ways, and that deliberate and thoroughgoing steering mechanisms, such as through the
Sustainable Development Goals The Sustainable Development Goals (SDGs) or Global Goals are a collection of 17 interlinked objectives designed to serve as a "shared blueprint for peace and prosperity for people and the planet, now and into the future".United Nations (2017) R ...
, are urgently needed. The signs of decaying planetary integrity are apparent from the negative
human impacts on the environment Human impact on the environment (or anthropogenic impact) refers to changes to biophysical environments and to ecosystems, biodiversity, and natural resources caused directly or indirectly by humans. Modifying the environment to fit the nee ...
and predictions showing that we are fast approaching global tipping points.


The "Limits to Growth" (1972) and Gaia theory

The idea that there are limits to the burden placed upon our planet by human activities has been around for a long time. The Planetary Boundaries framework acknowledges the influence of the 1972 study, '' The Limits to Growth'', that presented a model in which exponential growth in
world population In demographics, the world population is the total number of humans currently living. It was estimated by the United Nations to have exceeded 8 billion in November 2022. It took over 200,000 years of human prehistory and history for th ...
,
industrialization Industrialisation ( alternatively spelled industrialization) is the period of social and economic change that transforms a human group from an agrarian society into an industrial society. This involves an extensive re-organisation of an econo ...
,
pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, th ...
, food production, and resources depletion outstrip the ability of technology to increase resources availability. Subsequently, the report was widely dismissed, particularly by economists and business people, and it has often been claimed that history has proved the projections to be incorrect. In 2008, Graham Turner from the
Commonwealth Scientific and Industrial Research Organisation The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is an Australian Government agency responsible for scientific research. CSIRO works with leading organisations around the world. From its headquarters in Canberra, CSIRO ...
(CSIRO) published "A comparison of ''The Limits to Growth'' with thirty years of reality". ''The Limits to Growth'' has been widely discussed, both by critics of the modelling approach and its conclusions and by analysts who argue that the insight that societies do not live in an unlimited world and that historical data since the 1970s support the report’s findings. The ''Limits to Growth'' approach explores how the socio-technical dynamics of the world economy may limit humanity’s opportunities and introduce risks of collapse. In contrast, the Planetary Boundaries framework focuses on the biophysical dynamics of the Earth system. '' Our Common Future'' was published in 1987 by United Nations' World Commission on Environment and Development. It tried to recapture the spirit of the Stockholm Conference. Its aim was to interlock the concepts of development and environment for future political discussions. It introduced the famous definition for
sustainable development Sustainable development is an organizing principle for meeting human development goals while also sustaining the ability of natural systems to provide the natural resources and ecosystem services on which the economy and society depend. The ...
: Another key idea influencing the Planetary Boundaries framework is the Gaia theory or hypothesis. In the 1970s,
James Lovelock James Ephraim Lovelock (26 July 1919 – 26 July 2022) was an English independent scientist, environmentalist and futurist. He is best known for proposing the Gaia hypothesis, which postulates that the Earth functions as a self-regulating sy ...
and
microbiologist A microbiologist (from Greek ) is a scientist who studies microscopic life forms and processes. This includes study of the growth, interactions and characteristics of microscopic organisms such as bacteria, algae, fungi, and some types of para ...
Lynn Margulis presented the idea that all
organisms In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells ( cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fu ...
and their inorganic surroundings on Earth are integrated into a single self-regulating system. The system has the ability to react to perturbations or deviations, much like a living organism adjusts its regulation mechanisms to accommodate environmental changes such as temperature (
homeostasis In biology, homeostasis ( British also homoeostasis) (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physical, and chemical conditions maintained by living systems. This is the condition of optimal functioning for the organism and ...
). Nevertheless, this capacity has limits. For instance, when a living organism is subjected to a temperature that is lower or higher than its living range, it can perish because its regulating mechanism cannot make the necessary adjustments. Similarly the Earth may not be able to react to large deviations in critical parameters. In Lovelock's book ''
The Revenge of Gaia ''The Revenge of Gaia: Why the Earth is Fighting Back – and How We Can Still Save Humanity'' (2006) is a book by James Lovelock. Some editions of the book have a different, less optimistic subtitle: ''Earth's Climate Crisis and the Fate of Hu ...
'', he suggests that the destruction of rainforests and biodiversity, compounded with
global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
resulting from the increase of
greenhouse gas A greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor (), carbon dioxide (), methane ...
es made by humans, could shift feedbacks in the Earth system away from a self-regulating balance to a positive (intensifying) feedback loop.


Anthropocene

Scientists have affirmed that the planet has entered a new epoch, the Anthropocene. In the Anthropocene, humans have become the main agents of not only change to the Earth System but also the driver of Earth System ''rupture'', disruption of the Earth System's ability to be resilient and recover from that change, potentially ultimately threatening planetary habitability. The previous geological epoch, the
Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
began about 10,000 years ago. It is the current
interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...
period, and was a relatively stable environment of the Earth. There have been natural environmental fluctuations during the Holocene, but the key atmospheric and biogeochemical parameters have remained within relatively narrow bounds. This stability has allowed societies to thrive worldwide, developing agriculture, large-scale settlements and complex networks of trade. According to Rockström ''et al.'', we "have now become so dependent on those investments for our way of life, and how we have organized society, technologies, and economies around them, that we must take the range within which Earth System processes varied in the Holocene as a scientific reference point for a desirable planetary state." Various biophysical processes that are important in maintaining the
resilience Resilience, resilient, resiliency, or ''variation'', may refer to: Science Ecology * Ecological resilience, the capacity of an ecosystem to recover from perturbations ** Climate resilience, the ability of systems to recover from climate change * ...
of the Earth system are also undergoing large and rapid change because of human actions. For example, since the advent of the Anthropocene, the rate at which species are going extinct has increased over 100 times, and humans are now the driving force altering global river flows as well as water vapor flows from the land surface. Continuing perturbation of Earth system processes by human activities raises the possibility that further pressure could be destabilizing, leading to non-linear, abrupt, large-scale or irreversible environmental change responses by the Earth system within
continent A continent is any of several large landmasses. Generally identified by convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continents. Ordered from largest in area to smallest, these seven ...
al- to planetary-scale systems.


Reception and debate about the overall framework

The 2009 report was presented to the General Assembly of the
Club of Rome The Club of Rome is a nonprofit, informal organization of intellectuals and business leaders whose goal is a critical discussion of pressing global issues. The Club of Rome was founded in 1968 at Accademia dei Lincei in Rome, Italy. It consists ...
in Amsterdam. An edited summary of the report was published as the featured article in a special 2009 edition of ''
Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
'' alongside invited critical commentary from leading academics like Nobel laureate
Mario J. Molina Mario José Molina-Pasquel Henríquez (19 March 19437 October 2020), known as Mario Molina, was a Mexican chemist. He played a pivotal role in the discovery of the Antarctic ozone hole, and was a co-recipient of the 1995 Nobel Prize in Chemis ...
and biologist Cristián Samper. Development studies scholars have been critical of aspects of the framework and constraints that its adoption could place on the
Global South The concept of Global North and Global South (or North–South divide in a global context) is used to describe a grouping of countries along socio-economic and political characteristics. The Global South is a term often used to identify region ...
. Proposals to conserve a certain proportion of Earth's remaining forests can be seen as rewarding the countries such as those in Europe that have already economically benefitted from exhausting their forests and converting land for agriculture. In contrast, countries that have yet to industrialize are asked to make sacrifices for global environmental damage they may have had little role in creating. The biogeochemist William Schlesinger queries whether thresholds are a good idea for pollutions at all. He thinks waiting until we near some suggested limit will just permit us to continue to a point where it is too late. "Management based on thresholds, although attractive in its simplicity, allows pernicious, slow and diffuse degradation to persist nearly indefinitely.".


Subsequent developments


The "safe and just space" doughnut


National environmental footprints

Several studies have assessed environmental footprints of nations based on planetary boundaries: for Sweden, Switzerland,Hy Dao, Pascal Peduzzi, Damien Friot
'' National environmental limits and footprints based on the Planetary Boundaries framework: The case of Switzerland''
, University of Geneva, Institute for Environmental Sciences, GRID-Geneva, EA - Shaping Environmental Action, 2018.
the Netherlands,Paul Lucas, Harry Wilting
''Towards a Safe Operating Space for the Netherlands: Using planetary boundaries to support national implementation of environment-related SDGs''
PBL Netherlands Environmental Assessment Agency 2018.
the European Union, India, many of Belt and Road Initiative countries as well as for the world’s most important economies. While the metrics and allocation approaches applied varied, there is a converging outcome that resource use of wealthier nations – if extrapolated to world population – is not compatible with planetary boundaries.


Boundaries related to agriculture and food consumption

Human activities related to agriculture and nutrition globally contribute to the transgression of four out of nine planetary boundaries. Surplus nutrient flows (N, P) into aquatic and terrestrial ecosystems are of highest importance, followed by excessive land-system change and biodiversity loss. Whereas in the case of biodiversity loss, P cycle and land-system change, the transgression is in the zone of uncertainty—indicating an increasing risk (yellow circle in the figure), the N boundary related to agriculture is more than 200% transgressed—indicating a high risk (red marked circle in the figure). Here, nutrition includes food processing and trade as well as food consumption (preparation of food in households and gastronomy). Consumption-related environmental impacts are not quantified at the global level for the planetary boundaries of freshwater use, atmospheric aerosol loading (
air pollution Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different type ...
) and stratospheric ozone depletion.


Individual and collective allowances

Broadly described proposed solution-approaches based on a general a framework of ecological limits include (transferable) personal carbon allowances and "legislated" national greenhouse gas emissions limits. Consumers would have freedom in their (informed) choice within (the collective) boundaries.


Usage at international policy level


United Nations

The United Nations secretary general
Ban Ki-moon Ban Ki-moon (; ; born 13 June 1944) is a South Korean politician and diplomat who served as the eighth secretary-general of the United Nations between 2007 and 2016. Prior to his appointment as secretary-general, Ban was his country's Ministe ...
endorsed the concept of planetary boundaries on 16 March 2012, when he presented the key points of the report of his High Level Panel on Global Sustainability to an informal
plenary Plenary is an adjective related to the noun plenum carrying a general connotation of fullness. Plenary may also refer to: *Plenary session or meeting, the part of a conference when all members of all parties are in attendance **Plenary speaker, ...
of the UN General Assembly. Ban stated: "The Panel’s vision is to eradicate poverty and reduce inequality, to make growth inclusive and production and consumption more sustainable, while combating climate change and respecting a range of other planetary boundaries." The concept was incorporated into the so-called "zero draft" of the outcome of the United Nations Conference on Sustainable Development to be convened in Rio de Janeiro 20–22 June 2012. However, the use of the concept was subsequently withdrawn from the text of the conference, "partly due to concerns from some poorer countries that its adoption could lead to the sidelining of poverty reduction and economic development. It is also, say observers, because the idea is simply too new to be officially adopted, and needed to be challenged, weathered and chewed over to test its robustness before standing a chance of being internationally accepted at UN negotiations." In 2011, at their second meeting, the High-level Panel on Global Sustainability of the United Nations had incorporated the concept of planetary boundaries into their framework, stating that their goal was: "To eradicate poverty and reduce inequality, make growth inclusive, and production and consumption more sustainable while combating climate change and respecting the range of other planetary boundaries." Elsewhere in their proceedings, panel members have expressed reservations about the political effectiveness of using the concept of "planetary boundaries": "Planetary boundaries are still an evolving concept that should be used with caution ..The planetary boundaries question can be divisive as it can be perceived as a tool of the "North" to tell the "South" not to follow the resource intensive and environmentally destructive development pathway that rich countries took themselves... This language is unacceptable to most of the developing countries as they fear that an emphasis on boundaries would place unacceptable brakes on poor countries." However, the concept is routinely used in the proceedings of the United Nations, and in the ''UN Daily News''. For example, the
UNEP The United Nations Environment Programme (UNEP) is responsible for coordinating responses to environmental issues within the United Nations system. It was established by Maurice Strong, its first director, after the United Nations Conference on ...
Executive Director Achim Steiner states that the challenge of agriculture is to "feed a growing global population without pushing humanity's footprint beyond planetary boundaries." The
United Nations Environment Programme The United Nations Environment Programme (UNEP) is responsible for coordinating responses to environmental issues within the United Nations system. It was established by Maurice Strong, its first director, after the United Nations Conference on ...
(UNEP) Yearbook 2010 also repeated Rockström's message, conceptually linking it with
ecosystem management Ecosystem management is an approach to natural resource management that aims to ensure the long-term sustainability and persistence of an ecosystems function and services while meeting socioeconomic, political, and cultural needs. Although indig ...
and environmental governance indicators. In their 2012 report entitled "Resilient People, Resilient Planet: A future worth choosing", The High-level Panel on Global Sustainability called for bold global efforts, "including launching a major global scientific initiative, to strengthen the interface between science and policy. We must define, through science, what scientists refer to as "planetary boundaries", "environmental thresholds" and "tipping points"."


European Commission

The planetary boundaries concept is also used in proceedings by the
European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body ...
, and was referred to in the
European Environment Agency The European Environment Agency (EEA) is the agency of the European Union (EU) which provides independent information on the environment. Definition The European Environment Agency (EEA) is the agency of the European Union (EU) which provides ...
synthesis report ''The European environment – state and outlook 2010''.


See also

*
Ecological footprint The ecological footprint is a method promoted by the Global Footprint Network to measure human demand on natural capital, i.e. the quantity of nature it takes to support people or an economy. It tracks this demand through an ecological accounti ...
* Global catastrophic risk * Global change *
Holocene extinction The Holocene extinction, or Anthropocene extinction, is the ongoing extinction event during the Holocene epoch. The extinctions span numerous families of bacteria, fungi, plants, and animals, including mammals, birds, reptiles, amphibians, fish, ...
* Human impact on the nitrogen cycle *
Human impacts on the environment Human impact on the environment (or anthropogenic impact) refers to changes to biophysical environments and to ecosystems, biodiversity, and natural resources caused directly or indirectly by humans. Modifying the environment to fit the nee ...
*
Planetary health Planetary health refers to "the health of human civilization and the state of the natural systems on which it depends". In 2015, the Rockefeller Foundation and ''The Lancet'' launched the concept as the Rockefeller Foundation–Lancet Commission on ...
*
Planetary management Planetary management is intentional global-scale management of Earth's biological, chemical and physical processes and cycles (water, carbon, nitrogen, sulfur, phosphorus, and others). Planetary management also includes managing humanity’s influe ...
*
Sustainability Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livi ...


References


Sources

* * * * * * * * * * * * * * * * * * * * * * * * See also: Peak water. * * * * * * * * * * * The web page inverts the book title. * * * * * * * * *


External links


Figures and data
for the updated Planetary Boundaries can be found at the
Stockholm Resilience Centre The Stockholm Resilience Centre (SRC), is a research centre on resilience and sustainability science at Stockholm University. It is a joint initiative between Stockholm University and the Beijer Institute of Ecological Economics at the Royal Swe ...
website.
Planetary Boundaries: Specials
''
Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
,'' 24 September 2009.
Johan Rockstrom: Let the environment guide our development
TED video, July 2010
Transcript html
* {{Portal bar, Environment, Ecology, Earth sciences, Biology Earth sciences Global environmental issues Globalization Sustainability Criticism of capitalism