Large scale cultivation of Jatropha curcas, a shrub that thrives in harsh conditions, has been discovered to capture carbon, increase rainfall in desert areas, and cut the average desert temperatures.
Originating in South and Central America, the Jatropha shrub has now become active in other parts of the world including many African and Asian countries. The spread of this plant was catalyzed when Portuguese traders brought it to India where it was considered no more than a hedge by most for many years.
Today it is recognized for its resourcefulness and resiliency, surviving three years of drought by releasing its nutrient rich leaves which disperse as a soil enriching mulch. Yet the minimum amount of annual rainfall it needs to thrive amounts to a mere 2.36 inches. To put this in perspective, Death Valley, the driest area in North America, averages 2.25 inches of rain annually. Because it is also a perennial plant, the shrub can maintain productivity for thirty to forty years with its limited necessities.
Previously known for its energy dense seeds that, when crushed, produce oil as a new biofuel, and its ability to fight desertification, scientists have found that creating Jatropha plantations can prove successful in capturing carbon dioxide as well.
In fact, the researchers found that one hectare (nearly 2.5 acres) of a Jatropha plantation captures between 17-25 tons of carbon dioxide annually. Even more impressive, the costs for this carbon capture ranges from $56-72 per ton of gas, putting the plantations in competition with high tech carbon capture and sequestration.
According to the study’s lead author and the Director of the Atmosphere Project, Klaus Becker, if just three percent of the Arabian Desert was converted into these carbon capture plantations, all the carbon dioxide produced by cars in Germany would be absorbed over twenty years.
This increase in carbon capture is believed to also impact the average temperatures within the plantation’s region. “Our models show that, because of plantations, average desert temperatures go down by 1.1 degree Celsius (2 degrees Farenheit), which is a lot,” says Becker. Along with this decrease in temperature, the research team also found the plantations “induce rainfall in desert areas.”
But in order for these plantations to develop the capacity to grow such large quantities of Jatropha trees, two building blocks of growth are required: irrigation and nitrogen (to fertilize the trees).
To accommodate the first requirement, irrigation will be conducted through a desalination process. Becker also plans to reuse wastewater and sewage that are normally emptied into the ocean. By reusing this unexpected resource, costs that would be used for “expensive artificial nitrogen,” can be cut, improving the plantations’ cost efficiency.
With a fully functioning Jatropha plantation, the trees can begin to improve degraded soil, which have previously lost their fertility. This ability to grow in infertile areas removes a major argument environmentalists have brought against biofuels: land used for biofuels take away from food growers.
But just how much do Jatropha farms improve the fertility of the degraded land? Enough to improve a Madagascar farm’s organic matter content from 0.2% to 3%. This may not sound impressive, but “increasing soil organic matter from 1 to 3 percent can reduce erosion 20 to 33 percent” allowing for stable soil aggregation according to Eddie Funderburg, a soil and crops consultant for the Agricultural Division.
The importance of this plant cannot be understated. Its value triples as a biofuel producer, a soil enricher that increases the fertility of degraded land, and a carbon catcher with minimal requirements for its own subsistence and sustainability.
– Michael Carney
Sources: SciDev.Net, Wall Street Journal, Renewable Energy World, Western Regional Climate Center (WRCC), The Samuel Roberts NOBLE Foundation