The services of ecological systems and the natural capital stocksthat produce them are critical to the functioning of the
Earth’s life-support system. They contribute to human welfare, both directly and indirectly, and therefore represent
part of the total economic value of the planet.We have estimated the current economic value of 17 ecosystem services
for 16 biomes, based on published studies and a few original calculations. For the entire biosphere, the value (most of
which is outside the market) is estimated to be in the range of US$16–54 trillion (1012) per year, with an average of
US$33trillion per year. Because of the nature of the uncertainties, thismust be considered a minimum estimate. Global
gross national product total is around US$18 trillion per year.