Planetary Boundaries Explained
Nine Earth system processes keep the planet in the stable state that human society was built on. Seven of them have now been pushed past their safe limits.
What are planetary boundaries?
- A framework developed by the Stockholm Resilience Centre, first published in 2009.
- It identifies nine global processes that regulate the Earth’s stability, resilience and life support functions.
- For each one it sets a quantified safe limit for humans, a “safe operating space for humanity”.
- Crossing a boundary could generate unacceptable environmental change, potentially endangering human existence.
- The boundaries are interdependent. Only by respecting all nine can the safe operating space be maintained.
- They are dynamic, and revised as the science develops.
operating
space
High risk
Uncertainty
Beyond the safe zone lies a zone of uncertainty, and beyond that, high risk.
Source: Stockholm Resilience Centre; Planetary Health Check (2025)
The nine boundaries: where we stand
As of the 2025 Planetary Health Check, seven of nine boundaries have been breached.
Source: Stockholm Resilience Centre
The boundaries most material to nature and climate
Biosphere Integrity
Biodiversity loss and declining ecosystem function threaten the co-regulation of Earth’s energy balance and chemical cycles. Both genetic diversity and functional integrity sit outside safe levels.
Land System Change
The transformation of natural landscapes, through deforestation and urbanisation, disrupts habitats and biodiversity and diminishes ecological functions like carbon sequestration and moisture recycling.
Climate Change
Rising greenhouse gas concentrations trap heat, driving temperature increases and altered climate patterns. CO₂ levels continue to rise and this boundary is significantly transgressed.
Freshwater Change
Human-induced disturbance to both blue water (rivers, lakes) and green water (soil moisture) has exceeded the boundary. Altered freshwater cycles affect carbon sequestration and biodiversity, and can shift precipitation patterns.
Biogeochemical Flows (N & P)
Nitrogen and phosphorus sustain life, but industry and agriculture have disrupted their natural cycles. Runoff into the ocean creates dead zones, while industrial nitrogen fixation adds excess nitrogen to the system.
Ocean Acidification
Ocean pH has fallen roughly 0.1 units since the industrial era, about a 30% increase in acidity. This threatens calcifying organisms and reduces the ocean’s carbon sink capacity. Newly breached in 2025.
Source: Stockholm Resilience Centre
Ocean acidification: a closer look
Almost a quarter of human-caused CO₂ emissions are absorbed by the oceans, lowering the pH of seawater.
- CO₂ dissolves in seawater, forming carbonic acid and lowering pH.
- The ocean absorbs around 25% of all anthropogenic CO₂ emissions.
- Acidity has risen by roughly 30% since the pre-industrial era, a pH decline of about 0.1 units.
- Corals, shellfish and marine food webs are all under threat.
- The ocean’s capacity as Earth’s primary carbon stabiliser is reduced.
A reason for hope: the ozone layer
- Ozone depletion is one of the two boundaries still inside the safe operating space, and it is recovering.
- CFCs thinned the ozone layer, increasing harmful UV radiation reaching the Earth’s surface.
- The Montreal Protocol of 1987 coordinated a global phase-out of ozone-depleting substances.
- Total ozone is slowly but measurably recovering as a result.
We have done this before. Coordinated global action on a planetary boundary can work: the ozone recovery is proof that international cooperation, science-based policy and systemic change are possible.
What this means for impact investing
The framework gives investors a science-grounded way to think about where capital is most needed, and how to describe what it achieves.
Nature-climate is systemic
Nature and climate solutions address quantifiable risks to the systems that underpin all economic activity. An evidence-based rationale for institutional investors, beyond market trends.
A lens on investment themes
The nine boundaries are a natural way to test which impact themes address the most critically transgressed systems, and where a portfolio has gaps.
Language for additionality
Zones of uncertainty and high-risk thresholds give a precise vocabulary for what “additional” impact actually means.
A due diligence signal
Whether a fund manager can articulate the planetary boundary context of their investments is a signal of impact sophistication beyond standard ESG metrics.
Impact against absolute limits
Most impact reporting is relative, such as tonnes of CO₂ avoided per euro invested. The boundaries allow portfolio impact to be set against absolute, science-defined limits.
Interdependency risk
Because the boundaries interact, a climate-focused fund may inadvertently stress freshwater or nutrient cycles. Naming those dynamics strengthens the integrity of impact claims.
Ahead of disclosure
TNFD, the EU Taxonomy and SFDR are all moving toward nature-positive, science-based benchmarks that rest on this framework.
Boundary-specific mandates
Bespoke portfolios can be aligned to a single boundary: a freshwater allocation, or biogeochemical flows through regenerative agriculture and food system funds.
Key takeaways
Seven of nine planetary boundaries are now breached. We are outside the safe operating space for humanity.
The boundaries are interconnected: climate, biodiversity, land, water and nutrients must be addressed together.
Fragmented efforts are insufficient. Integrated action aligning climate, biodiversity and pollution policy is essential.
Accountability matters. Pledges must translate into measurable reductions within planetary boundaries.
The ozone story proves transformation is possible with coordinated global action.
Disclosure frameworks like TNFD are translating planetary boundaries thinking into financial decision-making.
Sources: Stockholm Resilience Centre; Planetary Health Check (2025); European Environment Agency (2025).