A Green View: Mapping Human Food and Fuel from Space
By Tariq Malik
Staff Writer
SPACE.com
29 June 2004
Sitting at the bottom of the food chain, the planet’s plant life feeds everything from cattle to human beings in one way or another.
With that in mind, a team of researchers have built a map of how much plant-derived resources we humans need to survive using a decade’s worth of satellite observations and some handy computer models.
“Plant life is the primary food source for all the life on Earth,” said Marc Imhoff, a lead researcher on the study at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s like the biofuel of the planet.”
Imhoff and his colleagues found that the global population consumes about 20 percent of the world’s plant life annually, which includes agricultural products for food and lumber for fuel, paper and other goods. While it may not seem like a lot, only a fifth of the global supply, some conservation researchers believe its a hefty amount.
“I think there’s cause for concern,” said Taylor Ricketts, director of conservation science for the World Wildlife Fund who also worked on the study. “In terms of the world’s biomass, we’re over consuming given our numbers.”
According to United Nations statistics, there are more than six billion humans living and consuming on Earth. That population, researchers said, represents about one percent of the world’s total biomass.
Zooming in on plants
To make their consumption map, researchers used 18 years of observations made by a series of Polar Orbiting Environmental Satellites (POES) operated by the National Oceanic and Atmospheric Administration. The satellites used reflected sunlight measurements to determine how much photosynthesis was carried out on Earth, giving researchers a foundation of plant life for their study.
Imhoff and his colleagues then used NASA-developed computer models not only the amount of consumable plant growth on land, but also the amount of land needed to grow feed for cows, pigs and other animals humans routinely use for food.
The effort resulted in a worldwide map of consumption that could be broken down to individual regions by population to compare how much an area such North America, for example, consumes with the amount it can produce locally - about 24 percent of its annual plant production.
Highly populated Western Europe and South Central Asia, one the other hand, each consume 70 percent of the greenery they produce.
“There’s an interesting trade-off between lower populations that are consuming more, and large countries that have to consume less,” Imhoff said.
North Americans, for example, consume up to four times per person than their counterparts in China. But because China’s population is so large - more than twice that of the U.S and Canada combined according to U.N. reports - the nation consumes more as a whole.
Understanding these consumption patterns could help researchers, agricultural policy makers and finally the food growers themselves better manage plant resources. Increased efficiency in food harvesting, as well as wood processing and paper recycling, could prevent excessive over consumption of resources. For example, industrialized nations can produce one ton of milled lumber from 1.3 tons of raw trees, whereas developing nations require at least two tons of raw materials due to less efficient technology.
“What we want to do in the end is try maintain the highest level of [agricultural] productivity so that future generations will be at the best possible present moment,” Imhoff said.
Urban greenery
The advent of the human metropolis has certainly put a bind on local plant food production, according to the new consumption map.
Rarely can such cities like New York City in the U.S., with a population of about eight million, support their populations on locally grown plant and animal resources. Such collections of humanity typically require more than 300 times what their regions can effectively produce, requiring daily imports of material to sustain their population.
“”The just can’t produce what they consume,” Ricketts said of such regions. “They’re kind of on life support as it is.”
A growing population could exacerbate such resource demands with, U.N. projections predicting a global population of more than seven billion people by 2015 and eight billion by 2030.
“You get an idea of how reliant we are on [food] transportation systems,” Imhoff said. “If these regions were constrained to what’s available locally, they wouldn’t survive.”
Other consumables
While the NASA study does look at the total land-based biomass available for human use, it is still an incomplete picture of our species’ consumption of the planet. The study fails to take into account the food contributions from the oceans through fishing.
“Obviously, we eat a lot out of the oceans,” Ricketts said, adding that future human consumption maps will have to take that into account. Such inclusive maps should also include fresh water supplies on a global scale, a resource that has been studied but not mapped based on its consumption, he added.
The study also lacks an accurate projection of the world’s annual consumption of fossil fuels such as oil or coal, on which so many countries depend. Once those fuel supplies have been exhausted, countries will have to find alternatives or else ramp up their lumber consumption through wood burning. Information on the trading of plant-based resources between regions and countries also requires further study.
“We’ll definitely want to look at how these products are traded,” Imhoff said. “There is a lot of [trade] going on and we’d like to know where those particular products come from.”
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Posted by: Paul on May 02, 2006 at 09:00:00