Elliot Campbell, Robert Genova and Christopher Field of the
Carnegie Institution's Department of Global Ecology, with David Lobell of
Stanford University, estimated the global extent of abandoned crop and pastureland and calculated their potential for sustainable bioenergy production from historical land-use data, satellite imaging and ecosystem models. Agricultural areas that have been converted to urban areas or have reverted to forests were not included in the assessment.
The researchers estimate that globally up to 4.7 million square kilometers (approximately 1.8 million square miles) of abandoned lands could be available for growing energy crops. The potential yield of this land area, equivalent to nearly half the land area of the United States (including Alaska), depends on local soils and climate, as well as on the specific energy crops and cultivation methods in each region. But the researchers estimate that the worldwide harvestable dry biomass could amount to as much as 2.1 billion tons, with a total energy content of about 41 exajoules. While this is a significant amount of energy (one exajoule is a billion billion joules, equivalent to about 170 million barrels of oil), at best it would satisfy only about 8% of worldwide energy demand.
"At the national scale, the bioenergy potential is largest in the United States, Brazil and Australia," says lead author Campbell. "These countries have the most extensive areas of abandoned crop and pasture lands. Eastern North America has the largest area of abandoned croplands, and the Midwest has the biggest expanse of abandoned pastureland. Even so, if 100% of these lands were used for bioenergy, they would still only yield enough for about 6% of our national energy needs."
The study revealed larger opportunities in other parts of the world. In some African countries, where grassland ecosystems are very productive and current fossil fuel demand is low, biomass could provide up to 37 times the energy currently used.
"Our study shows that there is clearly a potential for developing sustainable bioenergy, and we've been able to identify areas where biomass can be grown for energy, without endangering food security or making climate change worse," says Field, director of the Department of Global Ecology. "But we can't count on bioenergy to be a dominant contributor to the global energy system over the next few decades. Expanding beyond its sustainable limits would threaten food security and have serious environmental impacts."
This research was funded by the Carnegie Institution and by the Global Climate and Energy Project at Stanford University.
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Satisfied Water, Fertilizer, and land use needs using marginal, or even empty gravel pits making all the excuses why we can't leave our keyboards and git r done a very lame excuse indeed!
Get Blume's Opus and get with it. http://tinyurl.com/56rrda
We are talking about North America, not some imaginary Sim City where tens of thousands stand at attention, ready to build Your paradise to your specifications with unlimited money and resources.
Instead the proposal is quite modest: It requires NO waiting on technology advances, or permission from State or Federal Government entities. It solves part of river and stream pollution problems, negates coal, petroleum or natural gas for fertilizer, and does not tie up a single acre of prime cropland.
What's not to like, except for it might not be Your sacred idea?
Sir Richard Branson, We stand ready to solve Your fuel problems and do so at rates under current contract kerosene rates. Other Airline execs. reading this are also welcome to contact us via the FARMY. http://tinyurl.com/5nftmm