The Rainforest Action Network, Biofuelwatch and the Organic Consumers Association among other environmental groups sent a “letter of concern” this week to policymakers about the use of biochar to mitigate climate change.

Biochar is a charcoal-like soil additive made from cooking biowastes like chicken manure, wood chips and sewage sludge at high heat with little or no oxygen. The process, called pyrolysis, produces natural gases as well as biochar, which can be used in the soil to store carbon and increase fertility, according to the International Biochar Initiative and many scientists. (For a detailed explanation, see this piece I wrote for The Daily Green)

Large-scale production of biochar has been advocated as a way for farmers to go not just carbon-neutral but carbon-negative. By storing carbon in the soil and simultaneously increasing crop yields, biochar represents an exciting possible solution to global climate change and the global good crisis.

But, according to the “letter of concern” filed by environmental groups this week, policymakers should proceed with caution.  Citing lack of evidence, the groups warned that biochar production, which would need millions of hectares of  energy, would cause more harm than help. The groups warned that small airborne particles released from production, similar to  black soot, could contribute to global warming, that CO2 could be released  as a result of biochar addition to soil, and that large new demands  for biomass threaten remaining ecosystems.

According to a press release, Rachel Smolker from Biofuelwatch, said:

“A close look at the literature on biochar left me very concerned.  The claims made by people in the International Biochar Initiative, the  main biochar lobby group, are not well founded, they are lobbying hard  for massive supports through carbon market credits at the international  level and nationally. They have been lobbying UN delegates to endorse  biochar in the next climate agreement. In the US, a biochar bill was  introduced in Nevada just last week and they are keen on biochar carbon  offsets funding in the climate bill, allowing the UNCERTAIN carbon sequestration  benefit of biochar to be used, via the carbon market, to “offset”  the very CERTAIN smokestack emissions, and attain US emissions cap on  paper.. All of these efforts are based on hype, not science. Both the  United Nations Environment Programme and the Royal Society have urged  caution, as have over 150 civil society organisations.”

Perhaps we’ve gotten too excited, too soon about biochar, but hopefully lawmakers will “proceed with caution” while continuing to investigate biochar’s potential.

Photos: Treehugger.com

Graphic: visionshare via flickr

By Amelia Harnish