Some ecosystem services have an almost infinite value. Those that maintain the oxygen in the air we breathe, the quality of the water we drink and the fertility of the soil that produces our food are so basic to supporting life itself that these cannot even be evaluated.

Some ecosystem services are quite obvious and even visible. These are relatively easy to appreciate: fish, game, fruits and nuts from the wild. Many crops are pollinated by bees, butterflies, bats and other natural processes without which much of our food would be too expensive to produce. Maintaining the local micro-climate, controlling the spread of crop pests and diseases and binding the soil to prevent erosion are other services that ecosystems provide.

Less well known are the invisible services such as those that regulate the flow of nutrients through the ecosystem – nitrogen, carbon, phosphorus, sulphur and the rest. Without these, life itself let alone crops, forests, grasslands, mangroves, corals would not exist.

Ecosystem services are responsible for regulating, recharging and purifying our water bodies and help in mitigating floods, droughts and natural disasters. They are also required for producing timber, fuel, fodder and providing fibre for our industries.

Ecosystems are well-known for other services that are greatly valued by people: as habitats for biodiversity and migratory species; as enablers of ecotourism and many sports and recreational activities; and as sources of cultural values in the form of aesthetic beauty and intellectual stimulation.

Our economic systems do not fully acknowledge the value of such ecosystem services. Both as stocks (equivalent to primary wealth) and as flows (equivalent to the returns from that wealth treated as an investment), they are almost entirely neglected in our calculations of economic activity, GNP, stock market indices or other such parameters. Since they do not appear in any economic models, they are neglected by economists and therefore by policy makers.

The current crisis of climate change, oil, water scarcity, food price fluctuations, financial systems and many others amply demonstrate the dangers inherent in such a neglect. Designing strategies for sustainable development requires a much better understanding of nature’s services on the part of every concerned citizen.