It’s hard to attend any kind of energy or sustainability conference these days without needing to pop a Xanax, but at the 2012 US Biochar Conference, held this week in Sonoma County, California, excitement trumped angst handily. That’s because biochar is a simple technology with the potential to ameliorate no fewer than five dire global crises –topsoil depletion, nitrogen runoff, solid waste disposal, drought and, drum roll please…climate change.

Biochar is essentially charcoal that is ground up and incorporated as a soil amendment. It’s made by slowly burning anything from walnut husks to dead tree limbs to poop – just put that feedstock into a simple biochar stove (or bury it underground), light up and presto, you’ve got gas and charcoal, two valuable products for farmers grappling with high energy prices and poor soil fertility.

Long the province of farmers and gardeners, biochar is now attracting the attention of the climate change community for its massive carbon sequestration potential. Of the ten finalists for the Virgin Earth Challenge’s $25 million prize for a proven carbon capture technology, three are biochar companies.

Climate activists are fans of technologies like renewable energy that are carbon neutral -- that is, they don’t add any more friggin’ CO₂ to the atmosphere. But carbon neutrality alone won’t prevent us from reaching the dreaded tipping point climate scientist James Hansen warns of. According to Hansen, even if all fossil fuel emissions cease in 2015, we’ll still be above the safe limit of 350 ppm until the end of the century (we’re currently at 395 ppm, and CO₂ has a long shelf life). That means, Hansen and a growing number of climate scientists and activists agree, we need to scale up carbon negative technologies that suck CO₂ out of the atmosphere. Enter biochar which, alongside reforestation, grasslands restoration and regenerative agriculture techniques, can turn dust bowls into rich, lush carbon sinks. According to the Climate Trust , biochar has the potential to sequester 12% of the world’s current GHG emissions.

Carbon capture elicits skeptical groans among climate activists who suspect that behind every carbon capture scheme is a coal baron hocking “clean” coal. But biochar is different. For starters, it works. When vegetation decomposes, it releases CO₂ into the atmosphere. But if you process that vegetation (or poop) into biochar and then turn it into the soil, the carbon gets locked underground for, literally, a millennia.  Picture Al Gore’s inconvenient line graph showing a thousand-year plunge in CO₂ levels—booyah!

If the science is hard to grasp, think of it this way: The richer the soil, the more vegetation it can support, vegetation that inhales CO₂ and stores it in its roots. Biochar does double duty, not only locking up the carbon of the feedstock that went into its making, but also improving the soil’s ability to capture and retain water and organic matter.

For proponents of biochar (those who make it and use it), the current push is to create “designer” chars for specific soil conditions—a backyard gardener in suburban Texas needs a different biochar than a Haitian small landholder or a mega-farm in Wisconsin.  And farmers need a bit of convincing that shelling out $1000 for a ton of biochar will pay off in increased crop yields. Further research and field trials are underway to refine biochar’s properties and prove its efficacy. And small farmers in developing nations will need help building biochar stoves so they can produce their own home-grown biochar at low cost.

Biochar advocates also cite the need for the industry to organize itself into a trade association that can leverage the carbon credit markets, which could provide financial incentives for biochar producers and farmers who would be paid for the carbon they sequester. Finally, biochar enthusiasts are setting their sites on clean tech venture capital, hoping to entice impact investors to catalyze what Peter Hirst of New England Biochar calls “the greenest, most cost-effective, most socially useful carbon sequestration mechanism on the planet.”

 Erica Etelson is a writer and renewable energy fanatic based in Berkeley, California. Follow her on twitter @iluvsolar.