Biochar is a fine-grained, highly porous charcoal that helps soils retain nutrients and water. The carbon in biochar resists degradation and can sequester carbon in soils for hundreds to thousands of years.
Millions of dollars are being deployed on research into sequestration of carbon derived from burning coal in power stations This research is seen as a political and employment necessity. However, there are more simple and efficient ways to sequester carbon which are under exploration. The creation of biochar is one of them.
Ning Zeng is an atmospheric scientist at the University of Maryland. Zeng’s proposal was for the wood from thinning forests to be buried in deep trenches to lock away the carbon and prevent decomposition and release of carbon.
To take the matter further Zeng proposed growing and burying wood as a means of sequestering carbon. Zeng produced calculations indicating that the world’s current emissions could be offset with a workforce of one million persons.
These thoughts were taken further by the examination of black earth cultivated by the Amazonian peoples centuries ago. This black earth (terra preta) was made by heating organic matter to 350 degrees Centigrade (measures by experience) which retained the carbon as black ‘biochar’, the non-carbon constituents of wood and other organic matter being burned off. The biochar was then put back into the soil thus increasing its fertility. If this process could be applied to forest and other waste then burying in deep trenches would not be necessary.
Pilot industrial processes now indicate that it is possible to produce biochar and use the gases for energy production.
It is not suggested that biochar manufacture moves into Tasmanian forest, the science on this topic is absolutely clear—not one more tree from old growth forest should be felled because they represent the most significant carbon store on the planet.** In Tasmania at the moment under the label of ‘world best practice forestry’, the thinnings and debris from clear felling of native forests is burned on the forest floor. Carbon dioxide is released immediately. This process is damaging to forest biodiversity and the need for forests to provide an efficient ecological service as water catchments. It would not be appropriate to biochar these remnants because it would increase the possibility of more felling. However it might be an option for energy and biochar production from plantation thinnings.
Biochar offers great potential to the rural community in terms of jobs and income for the process is likely to be designed as a small industrial plant which can be used in rural areas. Furthermore, it offers a means of increasing the fertility and water holding capacity of agricultural soils at a time when these are deteriorating due to climate change.
Agriculture is Australia’s second-largest producer of greenhouse gases. Whilst these are not as yet calculated in international greenhouse accounting schemes, they will be in the future and in the meantime agriculture could prepare itself to be ‘carbon neutral’.
The Federal Opposition has made biochar a centre piece of its climate change strategy. While Malcolm Turnbull hasn’t yet signalled if he will support the Government’s emissions trading scheme, he has promised to slash missions by backing new technology. It is good policy to spread the reduction of grennhouse emissions across as many technologies as possible.
By contrast The Climate Change Minister, Senator Penny Wong said that for now the science of biochar is unproven. ( DEA comment—so is the sequestration of carbon from coal) In a statement, the Minister said: “Soil carbon (including biochar) does not fit within the scope of the current Kyoto Protocol accounts, so is not included at this time in the Carbon Pollution Reduction Scheme.” (DEA comment—so what, if it reduces carbon in the atmosphere , let’s get ahead and do it for there surely will be recompense if it works.
Further reading and viewing
Watch this 10 minute video
Read the article in the New Scientist “Carbon Lockdown” May 3, 2008
Look at these sites on the farming, manufacture of biochar
** The destruction of native forests throughout the world is increasing greenhouse emissions. The DEA policy “Human Health and Old Growth Forests” states “Doctors for the Environment Australia’s Forests Policy, based particularly on the health benefits of preserving old growth forests, argues that there is sufficient evidence to call for the preservation of all remaining Old Growth Forest (OGF) in Australia and throughout the world.” This policy was written in 2005 and since then the evidence for our case has become even stronger.