Contact:
David
E. Steitz
Headquarters, Washington
(Phone: 202/358-1730)
Krishna
Ramanujan
Goddard Space Flight Center,
Greenbelt, Md.
(Phone: 607/273-2561)
June 23, 2004 - RELEASE: h04-201
NASA SCIENTISTS GET GLOBAL FIX ON FOOD, WOOD & FIBER USE
NASA scientists working with the World Wildlife Fund andothers have measured how much of Earth's plant life humansneed for food, fiber, wood and fuel. The study identifieshuman impact on ecosystems.
Satellite measurements were fed into computer models tocalculate the annual net primary production (NPP) of plantgrowth on land. NASA developed models were used to estimatethe annual percentage of NPP humans consume. Calculations ofdomesticated animal consumption were made based on plant-liferequired to support them.
Marc Imhoff and Lahouari Bounoua, researchers at NASA'sGoddard Space Flight Center (GSFC), Greenbelt, Md., andcolleagues, found humans annually require 20 percent of NPPgenerated on land. Regionally, the amount of plant-basedmaterial used varied greatly compared to how much was locallygrown.
Humans in sparsely populated areas, like the Amazon, consumeda very small percentage of locally generated NPP. Large urbanareas consumed 300 times more than the local area produced.North Americans needed almost 24 percent of the region's NPP.
The study did not take into account NPP from the ocean. Italso did not include how trade between regions impactedequations. To map land NPP, researchers entered into a modela global satellite derived vegetation index and climate datafrom 1982 to 1998. The data came from the Advanced Very HighResolution Radiometer on the National Oceanic and AtmosphericAdministration Polar Orbiting Environmental Satellites. Themulti-year data set was processed at GSFC.
"This study uses the considerable technological assets ofNASA's Earth Science Enterprise to better understand how wecan maintain the highest possible production of food andfiber while still preserving our biological assets in theface of global change," Imhoff said.
By understanding patterns of consumption, and how theplanetary supply of plant life relates to the demand for it,these results may enable better management of Earth's richbiological heritage. Understanding the patterns of supply anddemand is critical for identifying areas of severe humanimpact on ecosystems and planning for future growth.
Consumption varies greatly by region, and this studypinpoints areas where human populations require importedbasic food, fiber and fuel. Regions with greater demands thanavailable plant-derived resources may be more vulnerable toclimate change and other socio-economic impacts. Imports mayput greater pressure on ecosystems elsewhere.
Three factors determine human regional ecological impact,population, per capita consumption and technology.
Population plays an important role. Americans consume morethan individuals in developing countries, yet U.S. populationdensity is generally lower. Technology helps reduce waste.For example, due to better technology, one ton of milledlumber requires 1.3 tons of trees in industrialized countriesbut more than 2 tons of trees in developing countries. As atechnologically advanced country, U.S. use of NPP is close tothe global average.
East and South Central Asia contain almost half the world'spopulation and appropriate 72 percent of regional NPP,despite consuming less per person than any region. Ifdeveloping nations raised consumption to match the developedworld's use per person, humans would consume more than 35percent of the total annual land NPP.
The research appears in this week's Nature Magazine. Forinformation and images about this research on the Internet,visit:
http://www.gsfc.nasa.gov/topstory/2004/0624hanpp.html
For information about NASA and agency programs on theInternet, visit: