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Biochar for carbon storage comes under fire

Some companies are developing techniques for making charcoal as a way to store carbon underground, but a group of conservationist warn against large-scale use.

A new idea for storing carbon dioxide underground using charcoal, or biochar, is being panned by organizations that oppose large-scale geoengineeringprojects.

The ETC Group on Monday published opposition to biochar from 147 small environmental and human rights organizations, calling the growing support for biochar a "dangerous new false solution to climate change."

Manmade coal produced by Carbonscape's Black Phantom machine. Carbonscape

Making charcoal--also called agrichar and terra preta--from organic matter like trees through low-oxygen burning, or pyrolysis, can improve soil while keeping carbon dioxide out of the atmosphere for thousands of years, say backers.

A number of companies are developing methods for making biochar as a strategy to stabilize carbon dioxide levels in the atmopshere. One New Zealand company called Carbonscape is developing a system that uses industrial-size microwave machines to turn wood, trash, and even sewage into biochar.

Carbonscape claims that its machine, called the Black Phantom, will sequester more carbon underground that the carbon dioxide generated for running its machine.

The ETC Group's organizations do not appear opposed to biochar outright. But they are clearly wary of polluters relying heavily on using bichar carbon offsets as a way to comply with carbon regulations.

Some environmentalists are in favor of using charcoal to store carbon underground and improve soil for agriculture--Carbonscape, for example, has some well known climate experts on its board. The warning by the ETC Group, which points to biofuels as an example, is a reminder to proceed with caution and common sense in implementing climate technologies.