Life Cycle Assessments using the PEF framework quantify product impacts across 16 environmental categories. The Planetary Boundaries framework, originally developed by Rockström et al. in 2009, takes a different approach, defining thresholds for humanity's total impact on Earth systems. Beyond these thresholds, we cannot reliably assume safe conditions for human societies. Understanding how these frameworks relate can provide useful context for interpreting LCA results.
This two-part series explores how these frameworks connect and what that connection means for interpreting LCA results:
Planetary Boundaries are a scientific framework first published by Rockström et al. in 2009 and regularly updated since. The concept defines a set of parameters, each with a threshold value within which the authors "expect that humanity can operate safely." If one or more of these boundaries is exceeded, this may entail drastic changes to environmental dynamics that could be destabilizing for human societies.
The framework examines humanity's collective impact - 'anthropogenic pressures on the Earth System' - making it fundamentally different from a product-level Life Cycle Assessment. While a PEF LCA quantifies a single product's impacts from raw materials through disposal, Planetary Boundaries assess whether humanity's total activity across Earth systems is within safe limits.
As of 2025, seven of the nine boundaries are transgressed, up from six in 2023.
The framework identifies nine critical Earth system processes, four of which include subcategories:
Some boundaries have evolved since their initial conception, reflecting updated scientific understanding. For example, Freshwater Change was originally defined as a flow rate of use/extraction. It has since been split into subcategories and updated to reflect human-induced disturbance calculated as a percentage of ice-free land area.
Each boundary is defined by specific metrics and threshold values. Below is a summary of the nine boundaries:
Selected Examples
For brevity, we've highlighted four boundaries below that illustrate different types of metrics and challenges. Full technical definitions for all nine boundaries are available in the Appendix.
Climate Change (Radiative Forcing)
This measure is more encompassing than CO₂ alone, including other greenhouse effect furthering substances such as methane and nitrous oxide or aerosols. The boundary is defined as 1 Watt per square meter above the reference value modelled for pre-industrial levels.
Land System Change
The boundary is defined as a percentage of potential natural forest cover, how much forest there could be without human activity. The boundary is set at 75%.
Biogeochemical Flows (Nitrogen)
This measures nitrogen that is fixed (extracted from the air and transformed into fertiliser and other industrial uses). The boundary is set at 62 Tg N per year.
Novel Entities
This boundary is defined as the percentage of human-made chemicals released to the environment without adequate testing. The boundary value is set at 0%, meaning any release of an untested or not-yet-understood compound is considered a breach. This includes plastics, persistent pollutants, microplastics, and tens of thousands of industrial chemicals protected as trade secrets.
Both frameworks quantify environmental impacts of human activities, but from different perspectives. The Planetary Boundaries framework takes a top-down view of the whole planet, considering all of humanity's activities for each boundary. An LCA typically examines a single product or activity and quantifies impacts over its whole life cycle from a bottom-up perspective.
Some of these boundaries align closely with PEF impact categories, such as climate change or freshwater change. Others are less directly aligned but still connected, for example, biodiversity relates to land use and other categories (we explored this connection in an earlier blog post).
An LCA, particularly a multi-criteria one such as PEF, provides insight into how significant a given product's impact is and where there is leverage to improve it. The Planetary Boundaries framework informs about current (usually annual) transgressions by humanity as a whole and thus provides an indication of what stresses the ecosystem is exposed to.
While they quantify at different scales and use different parameters, the two frameworks are connected. Understanding the global situation can help put LCA results into additional perspective.
In Part 2, we'll move from these scientific definitions to a practical exercise. You'll see how to review your PEF assessment through a planetary boundaries lens to identify potential regulatory risks, help prioritise reduction efforts, and communicate impacts to stakeholders.
We'll cover:
Climate Change (CO₂ Concentration)
The boundary is defined by atmospheric CO₂ concentration. The threshold value is 350 parts per million, which aligns with the Paris Climate Agreement target.
Climate Change (Radiative Forcing)
This measure is more encompassing, including other green house effect drivers such as methane and nitrous oxide, as well as aerosols. The boundary is defined as 1 Watt per square meter above the reference value modelled for pre-industrial levels.
Change in Biosphere Integrity (Genetic Diversity)
This boundary uses extinction rate as a proxy that may be replaced once better data becomes available. The baseline is assumed as one species per million going extinct per year, and the boundary value is set at tenfold that rate, so ten out of one million species going extinct per year.
Change in Biosphere Integrity (Functional Integrity)
This boundary is somewhat more abstract, using "a computable proxy for photosynthetic energy and materials flow into the biosphere." This represents the human appropriation of the biosphere's net primary production of carbon i.e. how much carbon bound in living matter we remove from the ecosystem. The boundary is provisionally set at 10% of pre-industrial net primary production.
Land System Change
The boundary is defined as a percentage of potential natural forest cover, how much forest there could be without human activity. The boundary is set at 75%.
Freshwater Change (Blue Water)
The boundary is defined as a percentage of ice-free land area with strong wet or dry deviations in streamflow of blue water (e.g. surface freshwater or groundwater reservoirs) relative to pre-industrial baseline. The boundary is set at 12.9% (the baseline value is 10.3%).
Freshwater Change (Green Water)
This boundary is similarly defined, but for soil moisture available to plants. The boundary is 12.4% (with a reference baseline of 9.8%).
Biogeochemical Flows (Phosphorus)
This measures how much phosphorus (used as fertiliser) is annually released to the environment. There are two boundary values: the global boundary (11 Tg P per year) measures phosphorus flow into the ocean, while the regional boundary represents the global sum of all regional limits at 6.2 Tg per year of phosphorus release.
Biogeochemical Flows (Nitrogen)
This measures nitrogen that is fixed (extracted from the air and transformed into fertiliser). The boundary is set at 62 Tg N per year.
Ocean Acidification
The boundary is based on the impact of CO₂ being absorbed into the oceans. It's defined by the saturation state of aragonite (a form of calcium carbonate used by organisms such as corals and shellfish), which decreases with higher CO₂ concentrations. The saturation state is defined as the availability of carbonate in seawater relative to the amount needed for a stable aragonite formation. The boundary value is set to 2.86 as a global mean, representing 80% of the pre-industrial value.
Atmospheric Aerosol Loading
This boundary considers light-absorbing particles in the atmosphere. Rather than measuring the total amount, it focuses on how unevenly the release occurs, particularly between the northern and southern hemispheres. This matters because absorbed or reflected light alters energy flows and with them wind/cloud dynamics and hydrological cycles. The metric measures the light absorption by the particles in the air as a value from 0 (none) to 1 (all). The boundary value is defined by the difference obtained from subtracting the average of the southern hemisphere from that of the northern one. The boundary value is set at 0.1
Stratospheric Ozone Depletion
The boundary is based on the Dobson UnitThis represents the amount of ozone in a column of air that would form a layer of 0.01mm if it was separated and compressed to 1 atm of pressure at 0°C. This boundary is, as a preliminary estimate, set to 277.4 DU.
Novel Entities
This boundary is defined as the percentage of the number of types of human-made chemicals released to the environment without adequate testing. The boundary value is set at 0%, meaning any release of an untested or not-yet-understood compound is considered a breach. This boundary highlights that little is known about many chemicals released into the environment, in many cases because the chemicals in question are protected as trade secrets and are not verifiably tested.