Sustainability thresholds and norms refer to the limits and standards that define what is environmentally and socially sustainable. These thresholds and norms are based on scientific and social understanding of the limits of the Earth’s resources and the capacity of ecosystems to provide goods and services.
Sustainability thresholds are the maximum limits of resource use and pollution emissions that can be sustained without causing irreversible damage to the environment or depleting natural resources. For example, the threshold for greenhouse gas emissions is the amount that can be emitted without causing the planet to warm more than 1.5 degrees celsius above pre-industrial levels, which is the threshold for avoiding dangerous climate change.
Sustainability norms are the standards of behavior and consumption that are considered sustainable. These norms are based on the principles of social and environmental justice, and they take into account the impacts of human activities on the natural world and on vulnerable populations. For example, a sustainability norm may be that everyone has the right to access clean drinking water, and that water resources should be managed in a way that ensures their long-term sustainability.
Sustainability thresholds and norms are important for guiding decision-making and action towards a more sustainable future. They help to identify the risks and trade-offs associated with different choices and actions, and they provide a framework for evaluating the sustainability of policies, practices, and technologies.
However, sustainability thresholds and norms are not fixed or absolute, and they may vary depending on the local context and values. They also need to be continually re-evaluated and updated as our understanding of environmental and social systems evolves.