A variety of ecosystems are spread across the world, each with distinctive interacting characteristics and components. They range from small (eg a freshwater pond) to global (eg the desert biome).

Tropical rainforests are an important ecosystem with distinct characteristics and adaptations. Tropical rainforests face threats which need to be managed to ensure their survival.

Many places around the world are affected by droughts. They can be caused by a lack of precipitation and also by human activity. Hundreds of millions of people lack a reliable water supply.

Polar environments provide opportunities for development but also face risks from a range of human activities, which will require sustainable management solutions.