Design of water harvesting towers and projections for water collection from fog and condensation.

Fresh water sustains human life and is vital for human health. It is estimated that about 800 million people worldwide lack basic access to drinking water. About 2.2 billion people (nearly one-third of the global population) do not have access to a safe water supply, free of contamination. Also, over 2 billion people live in countries experiencing high water stress. Current supply of fresh water needs to be supplemented to meet future needs. Living nature has evolved species which can survive in the most arid regions of the world by water collection from fog and condensation in the night. Before the collected water evaporates, species have mechanisms to transport water for storage or consumption. These species possess unique chemistry and structures on or within the body for collection and transport of water. In this paper, an overview of arid desert conditions, water sources and plants and animals, lessons from nature for water harvesting, and water harvesting data from fog and condensation are presented. Consumer, emergency and defence applications are discussed and various designs of water harvesting towers and projections for water collection are presented. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 3)'.