Press Release

NASA Scientists Get Global Fix on Food, Wood & Fiber Use

By SpaceRef Editor
June 23, 2004
Filed under ,

NASA scientists working with the World Wildlife Fund and
others have measured how much of Earth’s plant life humans
need for food, fiber, wood and fuel. The study identifies
human impact on ecosystems.

Satellite measurements were fed into computer models to
calculate the annual net primary production (NPP) of plant
growth on land. NASA developed models were used to estimate
the annual percentage of NPP humans consume. Calculations of
domesticated animal consumption were made based on plant-life
required to support them.

Marc Imhoff and Lahouari Bounoua, researchers at NASA’s
Goddard Space Flight Center (GSFC), Greenbelt, Md., and
colleagues, found humans annually require 20 percent of NPP
generated on land. Regionally, the amount of plant-based
material used varied greatly compared to how much was locally

Humans in sparsely populated areas, like the Amazon, consumed
a very small percentage of locally generated NPP. Large urban
areas 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. It
also did not include how trade between regions impacted
equations. To map land NPP, researchers entered into a model
a global satellite derived vegetation index and climate data
from 1982 to 1998. The data came from the Advanced Very High
Resolution Radiometer on the National Oceanic and Atmospheric
Administration Polar Orbiting Environmental Satellites. The
multi-year data set was processed at GSFC.

“This study uses the considerable technological assets of
NASA’s Earth Science Enterprise to better understand how we
can maintain the highest possible production of food and
fiber while still preserving our biological assets in the
face of global change,” Imhoff said.

By understanding patterns of consumption, and how the
planetary supply of plant life relates to the demand for it,
these results may enable better management of Earth’s rich
biological heritage. Understanding the patterns of supply and
demand is critical for identifying areas of severe human
impact on ecosystems and planning for future growth.

Consumption varies greatly by region, and this study
pinpoints areas where human populations require imported
basic food, fiber and fuel. Regions with greater demands than
available plant-derived resources may be more vulnerable to
climate change and other socio-economic impacts. Imports may
put 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 more
than individuals in developing countries, yet U.S. population
density is generally lower. Technology helps reduce waste.
For example, due to better technology, one ton of milled
lumber requires 1.3 tons of trees in industrialized countries
but more than 2 tons of trees in developing countries. As a
technologically advanced country, U.S. use of NPP is close to
the global average.

East and South Central Asia contain almost half the world’s
population and appropriate 72 percent of regional NPP,
despite consuming less per person than any region. If
developing nations raised consumption to match the developed
world’s use per person, humans would consume more than 35
percent of the total annual land NPP.

The research appears in this week’s Nature Magazine. For
information and images about this research on the Internet,

For information about NASA and agency programs on the
Internet, visit:

SpaceRef staff editor.