Humans are making huge changes to the Earth. Forests are being felled, wetlands drained and the oceans polluted.

As habitats disappear, so do the species that live in them. Air pollution caused by the burning of fossil fuels - coal, oil and gas - in the home, by power stations and transport, contributes not only to climate change, but also to health problems such as asthma.

The pressures on our planet have become so great that an urgent rethink about how we behave is now necessary if we are to have a world that we and our children will want to live in.