Desert 'carbon farming' to suppress CO2

1 August 2013

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By Matt McGrath

Environment correspondent, BBC News

Scientists say that planting great deals of jatropha trees in desert locations might be an effective method of suppressing emissions of CO2.

Dubbed "carbon farming", researchers say the idea is economically competitive with state-of-the-art carbon capture and storage jobs.

But critics state the concept might be have unexpected, unfavorable effects consisting of driving up food prices.

The research has actually been published, external in the journal Earth System Dynamics.

Seeds of change

Jatropha curcas is a plant that came from Central America and is very well adjusted to severe conditions including exceptionally dry deserts.

It is currently grown as a biofuel, external in some parts of the world because its seeds can produce oil.

In this study, German researchers showed that a person hectare of jatropha might capture approximately 25 tonnes of carbon dioxide from the environment every year. The researchers based their quotes on trees presently growing in trial plots in Egypt and in the Negev desert.

"The results are overwhelming," stated Prof Klaus Becker, from the University of Hohenheim in Stuttgart.

"There was great growth, a great reaction from these plants. I feel there will be no problem trying it on a much bigger scale, for instance 10 thousand hectares in the start," he stated.

According to the scientists a plantation that would cover three percent of the Arabian desert would absorb all the CO2 produced by cars and trucks in Germany over a 20 year duration.

The researchers state that a crucial element of the strategy would be the schedule of desalination facilities. This means that at first, any plantations would be restricted to coastal areas.

They are hoping to develop larger trials in desert areas of Oman or Qatar. Prof Becker says that unlike other plans that simply balance out the carbon that individuals produce, the planting of jatropha might be a good, short-term option to environment change.

"I believe it is a great concept because we are truly drawing out co2 from the environment - and it is completely various in between drawing out and preventing."

According to the researcher's calculations the costs of curbing carbon dioxide via the planting of trees would be in between 42 and 63 euros per tonne. This makes it competitive with other strategies, such as the more high tech carbon capture and storage, external (CCS).

A number of countries are currently trialling this innovation, external however it has yet to be released commercially.

Growing jatropha not only absorbs CO2 but has other benefits. The plants would help to make desert locations more habitable, and the plant's seeds can be harvested for biofuel say the scientists, supplying a financial return.

"Jatropha is perfect to be become biokerosene - it is even much better than biodiesel," said Prof Becker.

But other professionals in this area are not persuaded. They point to the reality that in 2007 and 2008 large numbers of jatropha trees were planted for biofuel, especially in Africa. But much of these ventures ended in tears,, external as the plants were not really successful in dealing with dry conditions.

Lucy Hurn is the biofuels project supervisor for the charity, Actionaid. She says that while jatropha was when seen as the excellent, green hope the reality was extremely various.

"When jatropha was introduced it was viewed as a miracle crop, it would grow on scrubland or limited land," she said.

"But there are often people who require limited land to graze their animals, they are getting food from that area - we would not class the land as limited."

She pointed out that jatropha is extremely hazardous and can contaminate the land it is grown on, even in a desert. And she likewise had issues about the fairness of the idea.

"It is still somebody else's land. Why enter and grow these huge plantations to handle an issue these individuals didn't in fact trigger?"

Follow Matt on Twitter, external.

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Related internet links

Universität Hohenheim

European Geosciences Union

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