Desert 'carbon farming' to suppress CO2

1 August 2013

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By Matt McGrath

Environment reporter, BBC News

Scientists say that planting big numbers of jatropha trees in desert locations could be an effective method of curbing emissions of CO2.

Dubbed "carbon farming", scientists state the idea is economically competitive with state-of-the-art carbon capture and storage projects.

But critics state the concept could be have unanticipated, unfavorable effects consisting of driving up food costs.

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

Seeds of change

Jatropha curcas is a plant that stemmed in Central America and is effectively adapted to harsh conditions consisting of very arid deserts.

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

In this study, German scientists showed that a person hectare of jatropha might capture approximately 25 tonnes of co2 from the environment every year. The scientists based their price quotes on trees currently growing in trial plots in Egypt and in the Negev desert.

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

"There was great growth, an excellent response from these plants. I feel there will be no problem attempting it on a much bigger scale, for example ten thousand hectares in the beginning," he said.

According to the scientists a plantation that would cover three percent of the Arabian desert would soak up all the CO2 produced by automobiles and trucks in Germany over a twenty years period.

The scientists say that a critical element of the plan would be the accessibility of desalination facilities. This suggests that initially, any plantations would be confined to seaside locations.

They are intending to establish bigger trials in desert locations of Oman or Qatar. Prof Becker says that unlike other schemes that simply offset the carbon that people produce, the planting of jatropha might be a great, brief term solution to environment modification.

"I think it is a great idea since we are really drawing out carbon dioxide from the atmosphere - and it is completely various between extracting and avoiding."

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

A variety of countries are presently trialling this innovation, external however it has yet to be deployed commercially.

Growing jatropha not only absorbs CO2 however has other advantages. The plants would assist to make desert areas more habitable, and the plant's seeds can be harvested for biofuel say the researchers, offering a financial return.

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

But other in this location are not convinced. They indicate the fact that in 2007 and 2008 big numbers of jatropha trees were planted for biofuel, especially in Africa. But many of these ventures ended in tears,, external as the plants were not extremely effective in managing dry conditions.

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

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

"But there are typically individuals who need limited land to graze their animals, they are getting food from that location - we would not class the land as marginal."

She explained that jatropha is highly hazardous and can pollute the land it is grown on, even in a desert. And she likewise had concerns about the fairness of the idea.

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

Follow Matt on Twitter, external.

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Related internet links

Universität Hohenheim

European Geosciences Union

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