In 1992, delegates from 178 governments came together in Rio de Janeiro for the UN conference on Environment and Development. The result was Agenda 21, a strategy that sought to weigh development needs against environmental concerns, globally, nationally and locally. ESD was part of that strategy, and in the UK, it was quickly woven into the national curriculum. Today, the practice of ESD varies from school to school. It is more of a philosophy than a subject: an approach to learning and living that permeates the culture of an entire school. While fostering a sense of responsibility for the environment, it encourages students to become articulate and caring citizens who will leave school with the confidence and knowledge to change society for the better.