sequestration

New Zealand's sheep farmers are flocking to a government carbon trading program that pays more to plant trees than sell wool and mutton.

The system, begun in 2008 and the only one of its kind outside Europe, awards farmers credits that are sold to offset greenhouse gas emissions. The project may earn them about $NZ600 a hectare ($193 per acre) a year on land unprofitable for grazing animals, said David Evison, a senior lecturer at the University of Canterbury's New Zealand School of Forestry.

Biochar—the agricultural application of charcoal produced from burning biomass—may be one of this century's most important social and environmental revolutions. This seemingly humble practice—a technology that goes back thousands of years—has the potential to help mitigate a number of entrenched global problems: desperate hunger, lack of soil fertility in the tropics, rainforest destruction due to slash-and-burn agriculture, and even climate change.

You report that "a British company's proposal to rent out one-fifth of Liberia's forests for carbon offsetting could have bankrupted the impoverished west African state" (UK firm's carbon offset deal 'could have bankrupted Liberia', 24 July). While this was certainly accurate reporting, it also missed a vital point – that this marks a vital step forward for Liberia.

Last year, there seemed to be an unwritten rule in enviro-circles: whenever two or more enviro-folks were gathered together in a place of meeting, talk must turn to biochar.

The UN Food and Agriculture Organization (FAO), as part of the UN Collaborative Programme on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (UN-REDD Programme), is developing a project to systematically analyze literature on methods used to measure and assess terrestrial carbon stocks, using an evidence-based approach.