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June 23, 2004
NASA Scientists Get Global Fix on Food,
Wood & Fiber Use
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 grown.
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, visit:
http://www.gsfc.nasa.gov/topstory/2004/ 0624hanpp.html
For information about NASA and agency programs
on the Internet, visit:
http://www.nasa.gov
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Contacts:
David E. Steitz
Headquarters, Washington
Phone: 202/358-1730
Krishna Ramanujan
Goddard Space Flight Center, Greenbelt, Md.
Phone: 607/273-2561
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Human Appropriation of Net Primary Production
This figure shows the global distribution of resource
consumption as measured by the amount of net primary
production (NPP) appropriated by humans. Global annual
NPP refers to the total amount of plant growth generated
each year. Plant growth may be measured in terms of grams
of carbon used to build stems, leaves and roots. The darker
areas on the map indicate greater appropriation of NPP by
humans. Credit: NASA
High-Resolution Image
Percent of Net Primary Production
Appropriated by Humans
This figure shows human appropriation of net
primary production (NPP) as a percentage of the
local NPP. The map provides insight into the
percent of plant resource used by people in an
area compared to the amount of plant resource
that is actually available locally. Credit: NASA
High-Resolution Image
Satellite Image of New York
City
This ASTER (Advanced Spaceborne Thermal
Emission and Reflection Radiometer) image shows
New York City and the Island of Manhattan,
bordered by the Hudson and East Rivers. The study
finds that people in some urban areas with very
high population densities need 300 times more
plant-derived resources, or net primary
production (NPP), than the local area
produces.
The image covers an area of 27 x 37 km, and was
acquired September 8, 2002.
ASTER is an imaging instrument that is flying on
Terra, a satellite launched in December 1999 as
part of NASA’s Earth Observing System
(EOS). Credit: NASA/GSFC/METI/ERSDAC/JAROS, and
U.S./Japan ASTER Science Team
High-Resolution
Image
The Brazilian Rainforest
This image shows the rain forest canopy north
of Manaus, Brazil. Humans in sparsely populated
areas with very high productivity, like the
Amazon, use very little of the region’s
NPP. As a result, human appropriation of NPP for
the Amazon region equals close to nothing.
Credit: NASA LBA-ECO Project
High-Resolution
Image
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