The quality of being able to continue over a period of time, or the avoidance of the depletion of natural resources in order to maintain an ecological balance (Camrbdige Dictionary).

This refers to 'the variability of living organisms, between and within species, and the changeability of the ecosystems to which they belong' (The Convention on Biological Diversity).

According to the Responsible Tourism Partnership, ‘Responsible Tourism requires that operators, hoteliers, governments, local people and tourists take responsibility, and take action to make tourism more sustainable. Behaviour can be more or less responsible, and what is responsible in a particular place depends on environment and culture’. The concept was defined in Cape Town in 2002 alongside the World Summit on Sustainable Development.

The process of protecting an environment and returning it to its natural state; for example, bringing back wild animals that used to live there (Cambridge Dictionary).

A movement reducing the distance between producers and sales and consumer establishments to a radius of under 100 kilometres, with the aim of minimising the effects that large-scale industry have on the planet, including soil erosion, water pollution, and habitat loss for wild species.

Being ‘green’ is used to describe actions or initiatives that are conducted in a sustainable way, in an attempt to reduce impact on planetary resource limits. However, the word can be used to describe actions or initiatives that do not actively do this, but rather convey an ethos of being planet-friendly; eg being outside, walking or riding a bike. This can be considered 'greenwashing' (when an individual or company paints an action as credibly sustainable when, in fact, it is an action that beenfits them, or that should be considered the bare minimum).