Thresholds and allocations


A sustainable future relies on ensuring that no one falls short on life’s essentials, and that collectively we do not overshoot our pressure on Earth’s life-supporting systems. Societal or ecological thresholds identified by science help establish the foundations and ceilings that earth and society should seek to operate within to prevent harm to people and the natural environment.

Figure 1: Social foundations and ecological ceilings

From a measurement perspective, this means that outcomes for people are sustainable if they are within the acceptable range determined by societal thresholds, and outcomes for the natural environment are sustainable if they are within the acceptable range determined by ecological thresholds.

The diagram below shows a simple representation of a threshold. An outcome within the acceptable range is positive/sustainable. An outcome outside the acceptable range is negative/unsustainable.

Figure 2: Societal and ecological thresholds determine what level of performance is ‘sustainable’

Research on thresholds is nascent and our understanding of them is growing all the time, meaning that consensus-driven thresholds may still fall short of those that truly indicate sustainability or the unsustainable tipping point. Where threshold and allocation methodologies are not yet available, organisations can engage in collaborative initiatives to work towards establishing their own. Ideally, thresholds and allocation methodologies are:

  • Rooted in the best available science on the relevant topic;
  • Applicable to the specific situation being measured (which can be verified through stakeholder feedback);
  • The most aspirational choice feasible; and
  • Transparently reported.

Thresholds are critical contextual reference points for organisations assessing whether an outcome is sustainable or unsustainable. They are distinct from other types of targets that organisations might set themselves which are not explicitly linked to a scientific assessment of what constitutes a sustainable outcome.  

Identifying thresholds

The nature of thresholds varies by type of sustainability topic. Some thresholds:

  • are rooted in physical realities of what the earth can sustain (planetary limits). Scientists set goals (such as a 1.5-degree scenario) that enable resource budgets to be set (in the case of climate change, relative to the global carbon budget)
  • are based on social sciences and the best-available research by experts (e.g. living wage)
  • are binary, where a positive outcome is the absence of harm (e.g. injury rate)
  • will be universally applicable based on science (e.g. biometric measures like HbA1c level for diabetes)
  • need to be contextualised to make the threshold locally applicable (e.g. wage level)
  • are quantitative (e.g. wage level, carbon budget)
  • are qualitative or criteria-based (e.g. UNICEF criteria for “safely managed” water)
  • are purely reflective of social norms or ethics.

Typically, only metrics that directly measure (or have an evidence-based link to) the outcome, and therefore to the level of well-being of people or the condition of the natural environment, have an associated threshold. For example, for a weight-loss programme there is a scientific range for a healthy Body Mass Index against which participant’s health (an aspect of well-being) can be assessed. Conversely, there is no scientific threshold for number of participants in the weight-loss programme, since this activity metric does not directly measure well-being.

This does not mean that proxy metrics should not be used where outcome measures are hard to identify. For example, measuring the percentage of board composition that is female does not indicate the well-being of women on the board, or more broadly in the company, with regards to equality and discrimination. Yet, it can be a useful indicator of the extent of an organisaton’s inclusive behaviours.


Whenever an organisation uses a shared resource or is part responsible for preserving or producing one, a further step is required to establish a fair allocation of the responsibilities involved. This becomes an organisation-specific threshold through a process called translation.

The most appropriate method of allocation varies by sustainability topic. For example, climate change involves apportioning shares of the responsibility to achieve an overall global carbon reduction target to individual emitters, whereas water use involves calculating the water availability in a watershed and fulfilling the needs of others (human and non-human) before assigning limits to individual organisations.

Figure 3: Metrics, thresholds and allocations

Allocation is the process of apportioning the responsibility to maintain thresholds in fair, just and proportionate ways that are specific to an organisation, making them practical for the organisation to apply when setting their own targets for measuring and managing sustainability performance.

Figure 4: Translating thresholds for use by organisations

Available thresholds

Science-Based Targets for Nature: Initial Guidance for Business

Last updated: 2020

This guidance helps organisations to set nature-related science-based targets. More generally, SBTn is embarking on a multi-year strategy to develop guidance for translating planetary thresholds and societal goals into company-specific targets for air, water, land, biodiversity and ocean.

Use this resource for the following Actions of Impact Management:

  • Set targets and plan: Set a company-specific target that references an ecological threshold for nature.

How To Guide For Setting Science Based Targets

Last updated: 2021

This guide briefly introduces a leading methodology for translating planetary thresholds related to greenhouse gas emissions into company-specific targets. It also provides further links to more detailed implementation guidance.

Use this resource for the following Actions of Impact Management:

  • Set targets and plan: Set a company-specific target for greenhouse gas emissions that incorporates an ecological threshold for a given global warming scenario.
  • The Science-Based Targets Network is developing further methodologies for determining thresholds and allocations for other topics such as biodiversity, land, oceans, and water.
  • The UNRISD Sustainability Performance Indicators project in partnership with r3.0 is helping companies to pilot sustainability performance indicators relative to thresholds.