Monday, March 30, 2009

Montbiots’ rejection of biochar

At first, I was somewhat confused by the critical texts against the use of biochar as a carbon dioxide reduction agent issued by the famous environmentalist George Monbiot.

Apart from some obvious exaggerations (‘turning the planet into charcoal’, 'primary source of world heating fuel’) and misunderstandings, he talks about the destructions of the forests, enormous monoculture plantations, and so on, that would be the effects of large scale use of charcoal, or biochar, as the term is used to differ it from fossil coal.

He also talks repugnantly and ironically against the obviously beneficial by-products of producing char; the increased plant production from the enhanced microbial activity achieved by mixing char into the soil, and the use of heat and tars emitted as by-products from the charring procedure (pyrolysis). He claims that biochar proponents say that these by-products could replace the use of fossil fuels throughout the world.

At first, I just thought that Monbiot and others with him, just reacted with some sort of conditioned reflex to protest against anything that looks as a behavioural turning or the introduction of a method that could be used generally, but is different from what we do today. However, Monbiots part of it surprised me, since he had earlier accepted and approved other issues that are far more radical.

But then, I realised what was the fundamental mistake, not only by Monbiot, but also by some of the biochar proponents.

Either, they think about removing all the excess carbon from the atmosphere.

Immediately, in one stroke.

That is at least 35 ppm worth, or 2.12 x 35 Gt carbon (= 75 Gt), or almost three times the current net annual plants production of coarse biomass. It would wipe out the plant cover.

Or, they think about removing all the current emission (8 Gt C) of carbon dioxide, plus hopefully, an extra Gt annually, to successively decrease the carbon dioxide content in the air and move out of the danger zone. That would require about two third of the annual production, leading to diversity loss and ruthless exploitation.

In that respect, Monbiot is perfectly right.

But, let us, just for a second, imagine that a responsible way to solve the problem of climatic carbon dioxide excess could be thread. Then, I imagine that a maximum of 15% -20% of the net annual biomass production could be appropriated for charring. That is about the same size as the global forestry sector, which certainly has had severe adverse effects on the face of Earth. But, in contrast to the forestry industry, biomass for carbonisation can be of any kind, from rice husks and other harvest surplus to twigs and branches, to plants purposely grown for carbon dioxide absorption.

Just look at your local environment with ‘the eyes of a sequester’! Plant production for food, to increase local diversity, or to absorb nutrient leakage does not exclude charring of the residues or decaying plants. A ‘black revolution’ does not necessarily exclude an ethically correct management.

Charring just 15% of the global net production does not considerably change the global atmospheric carbon dioxide content. But most of us agree that it is impossible to char more, because it will undermine our life support system, thus only let us jump from the frying-pan into the fire.

But here, the normally futile way of answering the climate change problem starts to make sense; If we, simultaneously with increasing charring, could considerably reduce our carbon dioxide emissions, say, with 90%, then, the emissions would be smaller than the possible sequestration! With the figures above, the sequestration exceeds the emissions with about 1-2 Gt per year.

This reduction in the use of fossil fuels will also reduce our capacity to make food from oil (We call this activity agriculture.), but that is another story…

Trying to obtain these combined goals means that we would have started a route towards a real decrease of the global carbon dioxide content together with a possible increase in biodiversity and soil fertility.

In the attached graph, a scenario assuming an increasing popularity of charring combined with an emission reduction to 90 % over a period of 20 years is assumed. Of course it is severely unrealistic, but it points out that there is a least a theoretical possibility to release ourselves out of the current problems. It also shows that such a Herculean effort also may stop the increase of the atmospheric carbon dioxide content within two decades.

[Be like the blackbird: It sees the morning long before the sun has risen]

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