Biochar

The final carbon reduction method that this blog will explore is upon us and how should we end this spell? With Biochar.

Biochar is created via a process known as pyrolysis, which is the combustion of organic material with little or no oxygen present. The outcome is a high density (black) carbon which can be used for carbon sequestration via underground terrestrial burial (Massachusetts Institute of Technology, 2009) (Seen below). Biochar has been championed due to its carbon storage capabilities, and its ability to enrich soils for crop production, hopefully enhancing a global food security (Levitan, 2010).

Source: DIY Natural

The idea to explore biochar as a carbon sequestration opportunity derived from the Amazon Rainforest. The terra preta soils were discovered to store 2.7 times as much carbon compared to regular soil (Glaser et al. 2001) but the idea had been speculated since 1996 by Kuhlbusch et al.

Biochar is actually produced by many farmers around the world as a fertiliser, and the pyrolysis is carried out in traditional kilns, which are easy to build and largely cheap to purchase (Massachusetts Institute of Technology, 2009). In order to translate biochar production onto a global scale, and as a geoengineering prospect, commercial pyrolysis machines are required. This is because the traditional method allows the escape of byproduct- synthetic gas (or syngas as it is known) which has a high carbon concentration and contributes to atmospheric carbon emissions. Commercial pyrolysis machines also reduce hydrocarbon levels, which also result from the pyrolysis process. It can be harvested as fuel if in liquid state, but residual (solid) hydrocarbons can actually limit crop productivity in plots with buried biochar. Ergo, commercial pyrolysis machines are therefore needed to prevent the result of residual hydrocarbon and have already solved the problem of potential carbon leakage to the atmosphere.

It has been suggested by Matovic (2011) that the combustion and burial of 10% of global biomass waste could sequester ~5 gigatons of Carbon per year. Putting this in perspective, humans emit 28 gigatons of carbon per year, of which a large proportion is taken up by the biosphere and oceans (Levitan, 2010) which means that global biochar production could have the potential to significantly reduce atmospheric carbon concentrations. Carbonscape have already been in talks of converting 930 hectares of land for biochar production (Monbiot, 2009) with hopes of being the first commercial company involved on a geoengineering scale!

Source: Re-Char

However, biochar has been a controversial proposal as to whether it really does classify as a geoengineering scheme. Surely it is just a method of carbon sequestration-  is its intent to be a large scale manipulation of the climate? This is why this post has become my ultimate carbon reduction post. Controversy revolves around its geoengineering status, but as long as it is still being considered as a potential geoengineering solution, it shall remain an interest within this blog feed!

Other concerns of biochar include that the global biochar initiative is subject to the same risks as any other carbon reduction method: The unknown. We cannot guarantee the outcome of global biochar- will it be successful? Can it respond to rapid climate changes? Will indirect consequences of land-use change or social or chemical problems arise? Similarly optimum biochar production would require a colossal number of commercial pyrolysis machines which is hugely expensive and largely impractical (Massachusetts Institute of Technology, 2009)! Can it possibly suit large scale implementation?

These questions are a constant to any geoengineering attempt, however, the difference between biochar and the carbon reduction attempts assessed so far, is that biochar is already happening at a local scale, and it is working. Even if this continued on a local scale alone, progress will be made to reduce atmospheric carbon concentrations, but as a geoengineering scheme- is it worth taking such a giant risk?

Apparently not yet anyway!

Source:Arctic Cartoons

Who knows, perhaps solar radiation methods will be more effective geoengineering techniques?

Until next time!


S xx