Functions performed by intact ecosystems provide essential support for human life, but how do we quantify their value?
Human life has evolved to depend on the functions performed by intact ecosystems. These ecosystem services include water and air filtration, flood control, pollination, moderation of disease spread, and natural beauty. All are vulnerable to degradation by human activity.
Ecosystem services, while interdependent, can be thought of in four categories: supporting (soil, habitat); regulatory (filtration, climate moderation); provisioning (food, water); and cultural (hiking, hunting). The biodiversity from which these services flow constitutes the natural capital on which human life depends. The World Bank estimates the annual worth of ecosystem services worldwide at $44 trillion—nearly twice the gross world product. But the UN’s 2005 Millennium Ecosystem Assessment found that, of 24 ecosystem services examined, 60% were being steadily degraded; one of the lead authors estimated that $3–$5 trillion of natural capital is lost every year.
Published October 2, 2012