Global patterns in human consumption of net primary production

• Published in: Nature 2004-06, Vol.429 (6994), p.870-873
• Main Authors: Imhoff, M.L, Bounoua, L, Ricketts, T, Loucks, C, Harriss, R, Lawrence, W.T
• Format: Article
• Language: English
• Subjects: agricultural resources; animal feeding; animal production; Animal, plant and microbial ecology; anthropogenic activities; Applied ecology; Atmosphere; Biodiversity; Biological and medical sciences; Conservation, protection and management of environment and wildlife; crop production; Earth (Planet); Ecosystem services; Ecosystems; Energy sources; Environmental impact; Environmental science; feeds; Food Chain; Food Supply; Food webs; forest resources; forest trees; forestry; Fundamental and applied biological sciences. Psychology; General aspects; geographical variation; global carbon budget; human appropriation of terrestrial net primary production; Human influences; Human populations; Humanities and Social Sciences; Humans; Imports; letter; Life sciences; multidisciplinary; Organic matter; Photosynthesis; Primary production; primary productivity; pulp and paper products; Science; Science (multidisciplinary); Solar Energy; wood products
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature02619

The human population and its consumption profoundly affect the Earth's ecosystems. A particularly compelling measure of humanity's cumulative impact is the fraction of the planet's net primary production that we appropriate for our own use. Net primary productionthe net amount of solar energy converted to plant organic matter through photosynthesiscan be measured in units of elemental carbon and represents the primary food energy source for the world's ecosystems. Human appropriation of net primary production, apart from leaving less for other species to use, alters the composition of the atmosphere, levels of biodiversity, energy flows within food webs and the provision of important ecosystem services. Here we present a global map showing the amount of net primary production required by humans and compare it to the total amount generated on the landscape. We then derive a spatial balance sheet of net primary production 'supply' and 'demand' for the world. We show that human appropriation of net primary production varies spatially from almost zero to many times the local primary production. These analyses reveal the uneven footprint of human consumption and related environmental impacts, indicate the degree to which human populations depend on net primary production 'imports' and suggest policy options for slowing future growth of human appropriation of net primary production.