4 Billion Years On

Planetary Boundaries

Nine limits that keep the Earth system stable - and how many humanity has already crossed…

In 2009, a team of Earth system scientists led by Johan Rockström identified nine processes that keep the Earth system stable. Together they define a “safe operating space” for humanity - limits that, once crossed, raise the risk of abrupt and irreversible environmental change. Here: where each of the nine stands today, from the latest Planetary Health Check, with live CO₂ and warming.

Latest data 25 Oct 2026

Current State

From the Planetary Health Check 2026: every crossed limit is still worsening, at its highest level on record, with food production and consumption the dominant driver.

Crossed

7 of 9

4 high risk · 3 increasing

Within Safe Limits

2 of 9

Aerosols and ozone

Atmospheric CO₂

426.9 ppm

Boundary 350 ppm

Global Warming

+1.46°C

Vs pre-industrial · Paris limit +1.5°C

Carbon DioxideHigh RiskBiosphere IntegrityHigh RiskLand-System ChangeIncreasing RiskFreshwater ChangeIncreasing RiskBiogeochemical FlowsHigh RiskOcean AcidificationIncreasing RiskNovel EntitiesHigh RiskAerosol LoadingSafeOzone DepletionSafe

Source: Planetary Health Check 2026 (PIK, September 2026), Richardson et al. 2023 and the Stockholm Resilience Centre. Warming and CO₂ are live readings; the temperature record is on the Global Climate Update.

The Nine Boundaries

Each Boundary Today

Pre-industrial level, the safe limit and where it stands now, from the Planetary Health Check 2026. High Risk and Increasing Risk are the report's two zones beyond the safe limit. Open Details for the science behind each one.

Carbon Dioxide (CO₂)

High Risk

The concentration of carbon dioxide in the atmosphere has surpassed safe limits, driving unprecedented global warming and destabilising Earth's climate systems.

Pre-industrial
280 ppm
Boundary
350 ppm
Now
426.9 ppm
Boundary

Biosphere Integrity

High Risk

Species are going extinct at more than 100 times the natural background rate - the most dramatic loss of life since the dinosaurs disappeared 66 million years ago.

Pre-industrial
~2 E/MSY
Boundary
<10 E/MSY
Now
>100 E/MSY
Boundary

Land-System Change

Increasing Risk

Forests, wetlands and other natural ecosystems are being converted to farmland and urban areas faster than they can recover, disrupting carbon, water and nutrient cycles.

Pre-industrial
~100%
Boundary
78%
Now
64%

Freshwater Change

Increasing Risk

Human alteration of river flows, groundwater extraction, and disruption of soil moisture is destabilising the global freshwater cycle far beyond safe limits.

Pre-industrial
Blue: 9.4% / Green: 9.8%
Boundary
Blue: 12.9% / Green: 12.4%
Now
Blue: 22.6% / Green: 22.0%

Biogeochemical Flows

High Risk

Industrial fertiliser production has flooded ecosystems with reactive nitrogen and phosphorus, creating ocean dead zones and toxic algal blooms worldwide.

Pre-industrial
0
Boundary
N: 62 · P: 6.2 Tg/yr
Now
N: 165 · P: 18.2 Tg/yr
Boundary

Ocean Acidification

Increasing Risk

The ocean has absorbed so much CO₂ that its chemistry is changing, becoming more acidic and threatening the survival of coral reefs, shellfish and marine food chains.

Pre-industrial
3.44 Ω
Boundary
≥2.86 Ω
Now
2.85 Ω

Novel Entities

High Risk

Over 350,000 synthetic chemicals - plastics, pesticides, PFAS 'forever chemicals' and more - are being released into the environment faster than we can assess their safety.

Pre-industrial
0
Boundary
0% untested release
Now
Transgressed

Atmospheric Aerosol Loading

Safe

Airborne particles from burning fossil fuels and biomass affect climate, monsoon patterns and human health - but globally this boundary remains within safe limits.

Pre-industrial
0.03
Boundary
0.1
Now
~0.07

Stratospheric Ozone Depletion

Safe

Thanks to the 1987 Montreal Protocol - the most successful environmental treaty in history - the ozone layer is recovering and this boundary remains within safe limits.

Pre-industrial
290 DU
Boundary
277 DU
Now
~286 DU
Coral Bleaching Tracker CO₂ Emissions

About the Framework

A Safe Operating Space

Where It Comes From

First published in 2009 by 28 Earth system scientists led by Johan Rockström of the Stockholm Resilience Centre and Will Steffen of the Australian National University. For the past 10,000 years - the Holocene - Earth has stayed remarkably stable, and farming, cities and technology all grew up inside that window. The framework names nine processes that keep it stable and sets a limit for each.

Seven Now Crossed

The 2026 assessment finds seven boundaries crossed. Four are in the high-risk zone - climate change, biosphere integrity, biogeochemical flows and novel entities - and three at increasing risk: land-system change, freshwater change and ocean acidification, the latest to cross in 2025. All seven are still worsening. Only atmospheric aerosols and stratospheric ozone remain within safe limits.

They Interact

Crossing one boundary raises the risk of crossing others. Climate change and biosphere integrity are the two “core” boundaries, because they shape the state of all the rest. Crossing a boundary is not the same as passing a tipping point, but it makes tipping points more likely.

We Can Pull Back

The ozone layer is the precedent. After the Antarctic ozone hole was found, the 1987 Montreal Protocol phased out the chemicals destroying it, and ozone has been recovering since the mid-1990s - proof that decisive action on clear science works, though the 2026 check warns the recovery may have plateaued.

Other Live Earth System Readings

Methane (CH₄)

1935 ppb

Second biggest greenhouse gas

Nitrous Oxide (N₂O)

339.9 ppb

From fertiliser and industry

Global Sea Ice · Sep 2026

22.13M km²

−2.07M km² against 1991–2020

Ocean Warming (2026)

+0.83°C

Sea surface anomaly

Data: NOAA, NASA GISS and global monitoring stations; sea ice from NSIDC (Arctic and Antarctic combined), as on Sea & Ice.

Key References

Climate Tipping Points Climate Change Explained

FAQs

FAQs

What are the planetary boundaries?

The planetary boundaries framework, first published by Johan Rockström and colleagues in 2009 and updated by the Stockholm Resilience Centre and the Potsdam Institute for Climate Impact Research, identifies nine processes that regulate the stability and resilience of the Earth system: climate change, biosphere integrity, biogeochemical flows (nitrogen and phosphorus), land system change, freshwater change, ocean acidification, atmospheric aerosol loading, stratospheric ozone depletion and novel entities (e.g. plastics, synthetic chemicals).

How many planetary boundaries have been crossed?

Seven of the nine, according to the Planetary Health Check 2026: climate change, biosphere integrity, biogeochemical flows and novel entities are in the high-risk zone, and land-system change, freshwater change and ocean acidification - which crossed its boundary in 2025 - are in the zone of increasing risk. All seven are still worsening. Only atmospheric aerosols and stratospheric ozone remain within the safe operating space.

How is the status of each boundary judged?

Each boundary has a "safe operating space" defined by one or more measurable indicators, such as atmospheric CO₂ for climate change or forest cover for land system change. Beyond the boundary lies a zone of increasing risk, and beyond that a high-risk zone. The Planetary Boundaries Science Lab at the Potsdam Institute for Climate Impact Research publishes an annual Planetary Health Check that places every boundary in one of these zones; each boundary's status is shown on its card on this page.

Is crossing a planetary boundary the same as a tipping point?

No. A planetary boundary marks the edge of the safe operating space - beyond it, the risk of destabilising the Earth system rises. Tipping points are specific thresholds where a system undergoes abrupt, often irreversible change (for example, ice-sheet collapse or Amazon dieback). Crossing a boundary makes triggering tipping points more likely but does not in itself constitute one.

Where does the data on this page come from?

Live indicators (CO₂, methane, N₂O, ocean warming) come from NOAA and global monitoring stations, and global sea ice from NSIDC. Boundary values and statuses are from the latest annual Planetary Health Check (Planetary Boundaries Science Lab, Potsdam Institute for Climate Impact Research), which builds on the framework first published by the Stockholm Resilience Centre.

How often is this page updated?

Live readings such as CO₂ refresh daily. The boundary status assessments refresh once a year when the Planetary Health Check is published, typically in autumn.

Is the planetary boundaries framework taught in schools and universities?

Yes. The planetary boundaries concept is a core framework in IB Environmental Systems and Societies (Topic 1: Foundations of ESS) and features in UK A-level Geography (global systems and governance) and AP Environmental Science (Unit 1: Earth systems, Unit 9: Global change). It is also widely used in university-level sustainability, earth science and environmental policy courses. The original paper (Rockstrom et al., 2009, Nature) and the 2023 update (Richardson et al., Science Advances) are freely accessible and listed at the bottom of this page.

How can I explain planetary boundaries simply for a school project?

Think of planetary boundaries as nine guard rails for the Earth. Within them, the planet remains stable and suitable for human civilisation - cross them and you risk triggering large, potentially irreversible changes. Scientists measure each boundary using specific indicators (for example, atmospheric CO₂ concentration for climate change, or the rate of species extinction for biosphere integrity). The safe limit, current status and trend for each boundary are shown on the cards on this page.