Three examples showing how human activity can result in pollution. The burning of forests in Indonesia causing smog in Kuala Lumpur; the production of farm slurry in Denmark, and the spilling of crude oil from a tanker.

Encourage students to investigate an environmental issue to which human impact may be a contributing factor. This could be a local issue, such as pollution in a local waterway, or a larger problem, such as falling fish stocks in the North Sea. Hold a class discussion as to how the contribution of a particular factor and the severity of the issue could be assessed. Both general ideas and specific fieldwork should be considered.