The major focus in all four themes is sustainability. There are many definitions of sustainability. Two well-known ones are:

1. The Brundtland Commission stated it is 'Development which fulfils the needs of the present generation without jeopardising the possibilities of future generations to fulfil their needs.'

2. The Countryside Commission have expended it to 'Sustainable development means meeting four objectives, at the same, in the UK and in the world as a whole. These are:


On a local, national, regional and global scale sustainability is implemented via:-

Agenda 21 (of the Earth Summits) - the main ideas include: