SciDev.Net

Biochar not only locks carbon into soil but is an effective fertiliser too

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[BONN] Campaigners have launched a protest against a proposed form of geoengineering that they say is gaining popularity despite being untested and fraught with potential social and environmental repercussions.

Biochar, at its most ambitious, involves recruiting vast amounts of biomass — for example, from dedicated plantations — and converting the carbon captured in the plant matter into charcoal. The charcoal is then ploughed into soils where it is hoped it will remain forever, improving soil fertility in the process.

The use of biochar is on the draft agenda for the international climate change negotiations in Copenhagen in December. Advocates have said it has the potential to absorb 5.5–9.5 gigatons of carbon each year.

Gambia, Ghana, Lesotho, Mozambique, Niger, Senegal, Swaziland, Tanzania, Uganda, Zambia and Zimbabwe have all called for the sequestration of carbon in soils, particularly biochar, to be included in global carbon trading — the mechanism by which the emission and absorption of carbon are punished and rewarded financially. The countries believe it is a way of addressing climate change, food and energy security as well as a means of regenerating degraded land.

But a coalition of nearly 150 organisations launched their campaign against biochar this week (6 April) during the Bonn Climate Change Talks, held in the run-up to the Copenhagen meeting. The group has likened enthusiasm for massive biochar production to the rush to biofuels, whose drawbacks only reached the public consciousness years later.

According to their report 'Biochar, a New Big Threat to People, Land and Ecosystems',meeting the most ambitious goals for biochar would mean recruiting 500 million hectares of industrial tree and crop plantations. 

The group, made up of small-scale farmers associations, forest protection groups, international environmental networks and human rights advocates, called on governments to study biochar in greater depth because of what they say is serious scientific uncertainty about both its ability to remove carbon from the atmosphere and side effects of its use.

"Everything has to be based on sound science. If there are controversies around the science then there should be more study on why they are being included," says Khamarunga Banda, a civil society researcher from Pretoria in South Africa.

Victoria Tauli-Corpuz, chairperson of the UN Permanent Forum on Indigenous Issues, says that an international drive to produce biochar might lead to the takeover of indigenous people's farmlands.

But Xavier Mugumya, national forest management specialist of the National Forestry Authority of Uganda, says that the Ugandan government has been pushing for the use of biochar to arrest land degradation and desertification as well as to help small-scale farmers generate carbon revenues.

And Alexander Mueller, assistant director-general of the UN Food and Agriculture Organization, says that global funding arrangements such as the Clean Development Mechanism do not offer sufficient incentives for farmers to get involved.

"We all have realised that agriculture has a huge carbon sequestration potential ... We have to develop methodologies and open the doors towards an upfront financing of all these projects."

Link to the report [393kB]