Leading the char

Biochar is black magic, our climate saviour

After the failure of world leaders at Copenhagen, it’s time for burnt offerings and some negative thinking to keep us positive.


Move over, carbon-neutral – yesterday’s watchword – and enter carbon-negative biochar, the great black hope that may allow us to breathe another day.

Charcoal power is warming the imaginations of scientists from the U.S. to Germany, Japan and the EU, and many projects are already functional. But though we have the Canadian Biochar Initiative and industry association Biochar Ontario nearby, our charboiled revolution is stalled on simmer.

What is this well-grounded tech all about? According to technologist and Biochar Ontario head Lloyd Helferty, we should think of the process as a “form of reverse mining” – taking carbon from the atmosphere and putting it in the earth.

It starts with waste from logging (twigs, bark, sawdust) and agriculture (straw, cornstalks, etc), which is subjected to low-temperature, low oxygen smouldering (pyrolysis). The charred remains are then put into the ground.

When these plant materials rot in the open air, they offer back to the atmosphere the carbon they absorbed in photosynthesis. But burial of carbon, which doesn’t break down for thousands of years, both keeps carbon from tampering with our climate any time soon and dramatically increases the yield of plants that feed people.

Imagine what a province-wide system of smouldering operations could mean for farmers, or for our emission tally. Some scientists estimate that the method could safely store 250 tonnes of carbon per hectare. And if every city had a facility to process yard waste and then redistribute the “black gold” to urban gardeners, we’d have a string of urban edens.

Over the last two decades, biochar has won the hearts and minds of a group of biologists, soil scientists and anthropologists fascinated by the soil-building practices of the first human inhabitants of the Amazon.

It’s believed that the Amazon’s “black earth,” as its soil is called, was produced thousands of years ago by early inhabitants who understood a process that modern scientists didn’t start to figure out until the 90s.

Early work on its rediscovery was done by Wim Sombroek, who was 10 years old during the Dutch famine of 1944, when his family survived on food from an exceptionally fertile backyard strewn with fireplace ash and cinders. When he saw black earth on a trip to the Amazon in the 50s, according to Emma Marris’s report in Nature in 2006, Sombroek recognized the magic of his childhood and devoted his scientific career to studying it.

Sombroek also worked with the young Johannes Lehmann, now a distinguished crop scientist at Cornell University. Lehmann and his co-workers deconstructed the wonders of carbon.

Carbon is very stable but it is also full of nooks and crannies and has high cation exchange capacity (CEC), in case you’re at a cocktail party with soil nerds. All these openings allow biochar to bind to water and other soil elements and keep them in place as well as providing hiding places for bacteria that break down nutrients in the soil.

Consequently, char keeps fertilizing nitrogen and phosphorous in the earth instead of letting them drain away and pollute rivers, and helps retains soil moisture. Food crops bloom – yields shoot up from 60 to 189 per cent at the sites Lehmann studied, while lakes and rivers remain stocked with fish.

On top of all this, the heat from the initial smouldering is capable of burning off half the carbon in the plant waste, converting it into bio-fuel and replacing fossil fuels.

Less carbon in the sky is not pie in the sky. Science policy advisers, including the European Union’s Frank Raes, support active biochar experimentation. Germany, the fast starter of green economics, already has a firm, the Juwi Group, which began manufacturing biochar from crop waste late in 2009.

The U.S. ag department spent over a million dollars to study the option. Japan already uses a third of its charcoal on farms. In Ontario, a commercial greenhouse in Kingston is handing over its scorched remains for farmers and experimenters.

But, says Helferty, who also serves on the leadership team of the Canadian Biochar Initiative, “Canada is quite far behind. There are no announcements of any funding, as far as I know,” he says. Wanted: a smouldering movement and politicians ready to bankroll it.


Leave your opinion for the editor...We read everything!

Your email address will not be published. Required fields are marked *

  • This Week’s Issue