Biochar - A Soil Building Climate Change Solution

Philip Greenwood
Tuesday, 18th October 2016

Biochar, charcoal made through pyrolysis, enriches poor quality and depleted soils, adding nutrients and beneficial microbes. It also sequesters carbon and can be a climate change solution.

Biochar is charcoal which is made at lower temperatures than ordinary charcoal (through a chemical process called pyrolysis) and which is used to enrich poor quality and depleted soils. Because it has a sponge-like structure beneficial microbes in the soil can colonise the biochar and so it becomes a 'coral reef' of nutrients for trees and plants to easily access through their roots. Not only does it lock important nutrients into the soil, it also sequesters carbon in the ground and in doing so mitigates against climate change, an important secondary benefit.

Terra Preta - the Amazon's Dark Earth

Biochar is an ancient technology which has re-emerged thanks to extensive research on biochar-rich dark earths in the Amazonian region. Ancient peoples used or deposited charcoal within the soil which had a wholesome effect on the surrounding microbiology and plant growth. We can see this in the remarkable health of the soil in these remote locations. It is not clear if they did this deliberately or if it was just a side effect of human habitation and intervention in the natural surroundings. However, in one area alone deep within the Amazon, a population of 10-15 million people were supported through integrated food systems. Compare this to the heavy yellow clay in much of the Amazon today, a difficult place to sustain crops long term, resulting in 'slash and burn' techniques, essentially a mass form of deforestation.

Biochar: a potent seed of possibility

Over time biochar has had the capacity to leave extraordinarily deep humus layers rich in microbiology and nutrients whilst at the same being an effective form of carbon sequestration. Due to its ability to remain a rich and fertile black earth, while still containing a high carbon content, biochar is a potent seed of possibility. With the issue of soil depletion reaching a crisis point all around the world and methane, carbon, and nitrogen levels rising, biochar becomes a realistic local solution to a number of interconnected global problems.

In 2009 The Royal Society presented biochar carbon sequestration as a solution to climate change. James Lovelock calls it a Biogenic Solution, after declaring that a massive burial of charcoal worldwide could solve our carbon problem. At the British Biochar Foundation conference last year I heard many stories that all held seeds of possibility for improved sanitation, food security, water infiltration and retention, fertility for depleted soils, carbon sequestration, reductions of methane, the list goes on (the Ithaka journal lists 55 uses for biochar). One story told of Vietnamese women using biochar to dissipate the smells of combined human, pig and compost waste, turning it into healthy soil that was used to increase both quantity and quality of plant production.

Climate Smart Agriculture

So, should we all be making biochar? If we started small in our own gardens it would make a significant impact, with small organisations like Sacred Earth aiming to fill the gaps and others worldwide working to help countries in the global south develop their own systems. Professor James Fairhead of the University of Sussex calls it 'Climate Smart Agriculture', his work and study leads him to believe that the most significant seeds of potential lie specifically in integrating within existing localised woodland and agricultural production systems. Biochar production on a small or medium scale which is integrated into an agrecological management plan is key to it becoming both a sustainable and a regenerative solution. At Sacred Earth we have adopted a closed loop system which utilises the abundant goat willow we have available at our 40 acre site - a pioneer species of tree which many people consider a weed.

On a national level, the British Biochar Foundation, which advocates biochar to help support the development of low carbon communities of tomorrow, may be the main vessel for us as individuals and small organisations to lobby collectively to bring this very local, small-scale solution to a number of big, interconnected environmental issues into the mainstream.

Phil Greenwood is the founder of Sacred Earth, a community land project based on a 40 acre site in East Sussex which is supported by the FEA Network's Just Growth funding programme. Sacred Earth has recently become a Community Benefit Society and they are currently running a community share offer to raise investment and welcome new members to the organisation. One of the key projects which will be supported through community investment is their biochar initiative.

Useful Biochar Links

Watch: Making and charging your own biochar

How to charge biochar