I believe that George Monbiot, in rubbishing the concept of biochar, misrepresents my work (Woodchips with everything. It's the Atkins plan of the low-carbon world, 24 March). "The great green miracle works like this: we turn the planet's surface into charcoal. Sorry, not charcoal ... Now we say biochar." I coined the word about four years ago. It doesn't mean charcoal like you burn on the barbecue, but finely divided pyrolysed (OK, George, "cooked" if you like) biomass prepared for soil improvement.

Monbiot says that I propose "new biomass plantations of trees and sugar covering 1.4bn hectares ... Read says the new plantations can be created across 'land on which the occupants are not engaged in economic activity'". But this degraded land is former forest that has been logged over and abandoned - not, as Monbiot says, "land occupied by subsistence farmers, pastoralists, hunters and gatherers". Given the chance, impoverished people often opt for a waged income. Does Monbiot wish to keep them impoverished for ever?

In reality there is not the shortage of land Monbiot implies but a desperate shortage of investment in the land. His "global total" of 1.36bn hectares of arable land does not include 2.38bn of unused potential arable land reported by the UN's Food and Agriculture Organisation, into which such investment, eg irrigation, might go. Moreover, the productivity of the 1.36bn could be raised with biochar pyrolysed from currently wasted agricultural residues, thus linking carbon removal with increased food supply and incomes.

Monbiot misses the point that the need for land-use improvements comes from the threat of climatic catastrophe. With too much carbon in the atmosphere and oceans, some of it has to be removed and put somewhere safer. Using the gift of nature - photosynthesis which enables green plants to use the sun's energy to absorb atmospheric carbon - is the only economic way.

One threat arises from the accumulation, summer after summer, of melt-water flowing down crevasses in Greenland's ice sheet to the rock surface under the ice, lubricating glacial flows into the oceans. Studies of pre-historic climate show that this happens suddenly, when the last sticking point gives way, raising sea levels by a metre or so, possibly in a decade. Arctic temperatures have to be brought down, not just stabilised. Emissions reductions alone, however drastic, cannot do that job.

The remedy is not "an easy way out" but needs hard work and good policy resulting in, to quote last year's Sustainable Biofuels Consensus, "a landscape that provides food, fodder, fibre, and energy; that offers opportunities for rural development; that diversifies energy supply, restores ecosystems, protects biodiversity, and sequesters carbon."

I do not want my grandchildren to be conscripted into the food, land and water wars that will break out unless an effective plan is devised and implemented. This would not involve usurping the rights of existing occupiers of the land but, since their rights and livelihoods will be extinguished anyhow in such wars, such usurpation would, if necessary, be preferable to catastrophic climatic change. Get your priorities sorted, George.

• Peter Read is an honorary research fellow at the Centre for Energy Research, Massey University, New Zealand

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