An Invention that Offsets CO2 Emissions

 2,500 Year Old Invention Can Reverse Global Warming 

Trees and Plants suck up CO2 as they grow, but then release it as they die and rot. However, we can prevent 50% of the CO2 being released when they die by turning the plants into biochar, which is fine grained carbon which can be buried in the ground where it remains safe for thousands of years. Pre Columbian Amazonian Indians have kept CO2 safe for over 2,500 years, which is a length of time that we must talk about when safely storing CO2. Biochar also cuts down on the need for fertilizers, reduces methane and nitrous oxides from the ground, filters out pollutants, and retains water. Quickly degrading rainforest soils caused by slash and burn farming can be kept fertile by the use of biochar.

There are two ways of producing biochar, we can smoulder plants without oxygen at a temperature of 350 degrees centigrade, or we can use hydrothermal carbonisation which steams organic material under pressure at 180 degrees centigrade using citric acid as a catalyst. Both processes readily produce heat which can be used to generate electricity of heat water.

Jim Amonette, a soil geochemist at the US Department of Energy's Pacific Northwest National Laboratory estimates that biochar would halt the rise in CO2 if we could biochar 8% of the Earth's annual biomass, while Green and Black co-founder Craig Sams has calculated that just 2.5% of the world's productive land were used to produce biochar then we could end the rise of CO2 emissions.

Trials are to be started in Sussex and Belize early in the new year, backed with venture capital from Silicon Valley, on techniques to take carbon from the atmosphere and bury it in the soil, where it should act as a powerful fertiliser, which will be scaled up rapidly into a worldwide enterprise which could bring atmospheric CO2 levels back down to pre-Industrial Revolution levels.

The ambitious enterprise, which on has just received its first multimillion-pound investment from California, is the brainchild of two of Britain's most successful environmental entrepreneurs: Craig Sams, one of the founders of the best-selling Green & Black's organic chocolate, and Dan Morrell, who co-founded Future Forests, the first carbon offsetting company.

They aim to grow trees and plants to absorb CO2 and then trap the carbon by turning the resulting biomass into biochar. There are three possible methods of converting vegetation to biochar, there could be a central plant, local farmers could share their own small plant, or mobile vehicles could do it for them. Whether a centralized system, a distributed system, or a mobile system is preferred is heavily dependent on the specific region. The cost of transportation of the liquid and solid byproducts, the amount of material to be processed in a region, and the ability to feed directly into the power grid are all factors to be considered when deciding on a specific implementation.

What we have to do, with this plan, is to put a charge on all goods and services equal to the amount of money it will take to make enough biochar to neutralise the CO2 emissions of the goods. This money would have to go to a central fund to pay for neutralisation of the CO2 produced. As Third World prices will be charged for the work the cost need not be too great, and yet would increase substantially to the $1.00 a day that many have to live on. Provided that the trees and plants are harvested sustainably and the biochar is buried in the areas of participating countries where the soil is the poorest, the quality improvement of the soil will increase the amount of food produced, and thus increase the wealth of the poorest.

 

Carbon Sink

The worlds soils hold more organic carbon than that held by the atmosphere as CO2 and vegetation, and the first one metre holds 1.5 times the amount of carbon than the total for the standing biomass, and 3.3 times the amount of the atmosphere.

 As most agricultural soils have lost 50 to 70% of their original carbon pool they represent a considerable carbon sink. Worldwide, the total release from burning crop residues is in the order of 3.6 to 6.4 billion tonnes of carbon per year, compared with 5.4 billion tonnes for fossil fuel consumption. A hectare of metre-deep biochar can contain 250 tonnes of carbon, as opposed to 100 tonnes in unimproved soils from similar parent material, according to Bruno Glaser, of the University of Bayreuth, Germany.

 

The History of Biochar

Terra Preta was discovered by Dutch soil scientist Wim Sombroek in the 1950s in the Amazon rainforest. Similar sites have since been found in Equador, Peru, Benin and Liberia in West Africa, and the savannas of South Africa and Liberia. The key ingredient is the activated carbon in the charcoal.

Amazon Terra Preta de Indio proves that infertile soils can be transformed into permanently fertile soils in spite of rates of weathering 100 times greater than those found in the mid-latitudes. The enhanced nutrient retention not only reduces the total fertilizer requirements but also the climate and environmental impact of crop lands. Char-amended soils have shown 50-80% reductions in nitrous oxide emissions and reduced runoff of phosphorous into surface waters and leeching of nitrogen into groundwater. Biochar systems can reverse soil degradation in areas with severely depleted soils, scarce organic resources, and inadequate water and chemical fertilizer supplies.

 

How Biochar Works

Modern biochars are attempts to recreate the Terra Preta of earlier times. It has an extremely high affinity to nutrients and it has an extremely high persistence, more than any other form of organic matter. These two properties address:

 

1) Soil degradation and food insecurity

2) Water pollution by agro-chemicals

3) Climate Change

 

Soils with biochar additions are typically more fertile, produce more and better crops for longer periods of time. Biochar is much more effective in retaining most nutrients and keeping them available to plants than other organic matter. This is also true for phosphorus which is not at all retained by 'normal' soil organic matter. Biochar lowers the density of clay soil, increasing the aeration and root penetration, while at the same time increasing sandy soils retention of water and nutrients. It also partially offset the acidity of nitrogen fertilizers.

 

In creating biochar there has to be sustainable management of biomass production. About 50% of the original carbon is retained in the biochar, which offers a significant opportunity for creating a carbon sink. The potential to combine bio-energy production, sustainable agriculture and waste management into one approach using biochar offers in many cases significant synergism for a combined strategy. Low temperature pyrolysis that yields bio-oil being the more advanced and more widespread technology. Renewable oils and gases co-produced in the pyrolysis process can be use as transport fuel or to generate heat. Biochar thus offers promise for its soil productivity and climate benefits.

 

 A program on the subject can be seen at: Agrichar-A Solution to Global Warming?Biochar has a complex, sponge like molecular structure. A single gram can have a surface area of 500 to 1500 square metres, which helps it retain water by creating little reservoirs. The surface area helps to bind nutrients in the soil. It has also been shown to be particularly a micro habitat for micro organisms such as arbuscular mychorrhizal fungi, which forms a symbiotic relationship with plant root fibres, allowing for greater nutrient uptake by plants. There is speculation that the mycorrhizal fungi may play a part in terra preta's ability to seemingly regenerate itself. As long as an 20 cm layer of biochar is left on the surface, it can regenerate itself to a depth of 300 cm over a period of two decades.

 

Recycling Bio Waste

Australian Minister for Primary Industries, Ian MacDonald, says: "Products like paper mill waste, green waste, animal manures or other biomass can be recycled by heating to 550 degrees C in the absence of oxygen, generating electricity and biochar. Recent studies have found a 150% increase in corn yield when biochar is applied at the rate of 20 tonnes to the hectare."

A program on the subject can be seen at: The Secret of Eldorado