Carbon-Negative is a new word for any strategy that can reverse global warming by removing greenhouse gases from Earth's atmosphere.

In 2008, leading climate scientists worldwide examined field data and computer simulations of climate, and concluded that 350ppm carbon dioxide is the maximum safe level for this greenhouse gas in Earth's atmosphere. Beyond that, many global warming effects accelerate, such as melting polar ice caps.

However, Carbon Dioxide is currently 387ppm, and still rising, faster than ever, so we are 37ppm beyond our best scientist's maximum safe level for climate stability.

Therefore, carbon-neutral is not enough. Merely reducing our emissions cannot restore stability to Earth's already overloaded thermal engine that drives climate and weather. Zero net emissions won’t lower the carbon level in the Earth’s atmosphere. We must rapidly initiate actions that remove greenhouses gases from the atmosphere-first and foremost, carbon-and thereby lower the level below the agreed-on safe maximum level. To have a stable, sustainable future, humanity must become carbon-negative.

Biochar is a new word for charcoal made from biomass for the purpose of adding to soils to stimulate physical and biological fertility. Properly charred, this form of reduced carbon remains stable in soil for centuries, and likely for millennia.

In 1992, Dutch soil scientist Wim Sombroek first proposed sequestering carbon as char in soils. The first international conference was in New South Wales, Australia in 2007; the second was in Newcastle, England last September. In June 2009, European Union adopted standards for production and use of biochar in agriculture. The first North American Biochar Conference is August 9-12, 2009 at University of Colorado at Boulder, and features an address by the USDA Secretary. In December, a Copenhagen climate negotiations, a Pacific Island nation endangered by sea level rise from global ice melt will propose priority recognition of biochar as an effective strategy to sequester carbon.

In essence, carbon-negative strategy is simple: let nature do it. Plants by photosynthesis combine CO₂ with water to create carbohydrates, and build their bodies from this cellulose fiber. When plant biomass is burned without oxygen, up to half the carbon is converted to charcoal-carbon in its most reduced, inert, least reactive form. If that charred carbon is put in soil, it remains there for centuries, likely for millennia, safely sequestered. And in soil, biochar nurses a remarkable transformation that greatly improves physical structure, tilth, nutrient storage capacity, and biological activity. This sustainable fertility allows farmers to reduce fertilizer use and grow nutrient-dense foods.

Biochar production also produces renewable energy. “Pyrolysis” of biomass distills out volatile chemicals that are captured to reprocess into biofuels and chemicals, while 30-50% of the carbon remains as biochar. This gasification technology can be adapted to optimize yield for hydrogen, syngas, bio-oil, wood vinegar, or other by-products from various feedstocks. Even if the biofuels are burned, if biochar is put in soil, this energy strategy is net carbon-negative.

In 2008, Dr. James Hansen, America’s leading climate scientist, evaluated scientific data on carbon-negative biochar strategy to calculate potential impacts on atmosphere and climate. Dr. Hansen’s paper published in August 2008 states:

“Carbon sequestration in soil has significant potential. Biochar, produced in pyrolysis of crop residues, forestry wastes and animal manures, can restore soil fertility while storing carbon for centuries to millennia. Biochar helps soil retain nutrients and fertilizers, reducing emissions of greenhouse gases such as N₂O. Replacing slash-and-burn agriculture with slash-and-char, using agriculture and forestry wastes for biochar production can provide CO₂ drawdown of ~8 ppm or more in half a century.”

Dr. Hansen agrees biochar strategy can sequester enough carbon to begin to mitigate climate change in half a century.

Carbon-negative biochar is our most effective natural strategy to sequester carbon, produce renewable energy, cut fertilizer use, reduce fossil fuels, reverse global warming, and address other key challenges. At its heart, this strategy transforms our use of fire from combustion to ash, to pyrolysis & gasification-controlled combustion-to yield energy, charcoal, assorted biofuels, and chemicals. Clearly, carbon-negative strategy using biochar is not an option or alternative, but essential and critical to assure a sustainable human future based on ecological restoration and stewardship.

Time is urgent to address our climate, energy and economic crises, and turn society in sustainable directions, so we are spreading this idea to put biochar in soil in our gardens, farms, homes, and communities, and teaching the methods. The public and public officials must quickly learn about this new carbon-negative concept, and support efforts to explore this new biochar strategy and to implement biofuel technology in farms, forestry, homes, businesses, and communities.