Normative generally means relating to an evaluative standard. Normativity is the phenomenon in human societies of designating some actions or outcomes as good, desirable, or permissible, and others as bad, undesirable, or impermissible. A norm in this sense means a standard for evaluating or making judgments about behavior or outcomes. "Normative" is sometimes also used, somewhat confusingly, to mean relating to a descriptive standard: doing what is normally done or what most others are expected to do in practice.
In ecology, urban ecosystems are considered a ecosystem functional group within the intensive land-use biome. They are structurally complex ecosystems with highly heterogeneous and dynamic spatial structure that is created and maintained by humans. They include cities, smaller settlements and industrial areas, that are made up of diverse patch types (e.g. buildings, paved surfaces, transport infrastructure, parks and gardens, refuse areas). Urban ecosystems rely on large subsidies of imported water, nutrients, food and other resources.
Sustainability is a social goal for people to co-exist on Earth over a long time. Specific definitions of this term are disputed and have varied with literature, context, and time. Experts often describe sustainability as having three dimensions (or pillars): environmental, economic, and social, and many publications emphasize the environmental dimension. In everyday use, sustainability often focuses on countering major environmental problems, including climate change, loss of biodiversity, loss of ecosystem services, land degradation, and air and water pollution.
Urban resilience has conventionally been defined as the "measurable ability of any urban system, with its inhabitants, to maintain continuity through all shocks and stresses, while positively adapting and transforming towards sustainability". Therefore, a resilient city is one that assesses, plans and acts to prepare for and respond to hazards, regardless whether they are natural or human-made, sudden or slow-onset, expected or unexpected. Resilient Cities are better positioned to protect and enhance people's lives, secure development gains, and drive positive change.
Sustainability measurement is a set of frameworks or indicators to measure how sustainable something is. This includes processes, products, services and businesses. Sustainability is difficult to quantify. It may even be impossible to measure. To measure sustainability, the indicators consider environmental, social and economic domains. The metrics are still evolving. They include indicators, benchmarks and audits. They include sustainability standards and certification systems like Fairtrade and Organic.
