Importance of Biodiversity

Conserving biodiversity is frequently justified on several distinct kinds of grounds, and understanding these different arguments -- rather than assuming there is only one reason biodiversity matters -- helps explain why conservation is pursued even for species that appear, at first glance, to offer no obvious direct benefit to people.

The narrowly utilitarian argument for biodiversity conservation rests on the direct, tangible economic products that humans obtain from other species. Biodiversity is the ultimate source of food crops, timber, fibres, and a very large share of modern pharmaceutical drugs -- a great many important medicines, from painkillers to anti-cancer compounds, were originally derived from, or are still directly sourced from, wild plants, fungi or animals. Because science has examined only a small fraction of the world's total described species in any real chemical or pharmacological depth, undiscovered biodiversity is widely viewed as a vast, largely untapped reservoir of future economically valuable products, which is itself a strong practical reason to prevent species from disappearing before they are ever properly studied.

The broadly utilitarian argument goes further, resting not on specific marketable products drawn from individual species but on the essential ecological services that biodiversity as a whole provides to the functioning of the planet -- services on which human society depends just as much as it depends on food and medicine, even though no individual price tag is attached to them. Forests and other vegetation, taken together, play a central role in producing atmospheric oxygen and in regulating the carbon cycle -- the Amazon rainforest alone is often cited as contributing roughly one-fifth of the oxygen entering the Earth's atmosphere, which is why it is sometimes referred to as one of the planet's 'lungs'. Biodiversity additionally underpins pollination of a great many food crops by insects, birds and other animals, purifies air and water, maintains soil fertility, moderates local climate, and provides flood and drought regulation through the water-retention capacity of healthy ecosystems such as forests and wetlands -- benefits that would be enormously costly, and in many cases practically impossible, for human technology to replace if the ecosystems providing them were lost. …