Would you like to curb or even reverse global warming? Help feed the world? Generate renewable energy?

Biochar is the answer, say its most fervent advocates.

If only life were so simple.

Biochar, alas, isn’t ready yet to be a meaningful solution to the climate crisis, or a way to enhance agricultural productivity at scale. But it’s an intriguing substance that has been around for thousands of years, and the production of biochar may prove to be one of the technologies that governments and business deploy to deal with the threat of climate change. As, potentially, a carbon negative technology, it’s worth a look.

Biochar, for those of you who haven’t heard of it, is a charcoal-like substance that is created today by pyrolysis of biomass. In layman’s terms, biochar is made by taking organic material, like agricultural waste, heating it to very high temperatures, and allowing it to decompose in the absence of oxygen.

To learn about biochar, I met recently in Boulder, Colorado, with Jonah Levine, who is a co-owner of his own small biochar business and, until recently, was an executive with a startup called Biochar Engineering. Jonah, who is 30 and lives near Boulder, got involved with biochar when a friend asked him to organize a conference on the technology in 2009 at the University of Colorado. A passionate environmentalist, he had previously worked as a wildlife biologist and as an engineer advising utilities on how to incorporate renewable energy into the grid.

Now he’s bullish on biochar.

“I feel like like I’m watching the beginning of an industry,” Jonah says. “Within a decade, I feel this will be a functional business space.”

He told me that the history of biochar can be traced back to Brazil, where dark soils in the Amazon region are known as “Terra Preta.” No one can be certain about their origin, but some scientists believe they were created as long as 4,500 years ago, and that they helped support a complex, farm-based civilization in the Amazon, despite the region’s poor soil.

Johannes Lehmann, a leading biochar researcher at Cornell University, writes:

Terra preta research inspired the development of a revolutionary technology that can have tremendous impact on rural livelihoods as well as carbon sequestration. It builds on the application of stable organic matter in the form of bio-char (biomass-derived black carbon or charcoal) in conjunction with nutrient additions. This bio-char is very stable, provides and retains nutrients for millenia, as seen in Terra Preta.

As Jonah explained it to me, organic matter—crop waste, wood chips or even sewage—can be turned into biochar by heating the materials to between 300 and 900 degrees C. This generates a synthetic gas that can be converted into liquid fuels, used for heating or generating electricity, as well as the biochar, which is then worked into soil to improve farm productivity. (The yield of products from pyrolysis varies with the temperature; lower temperatures produce more char, higher temperatures make more syngas.) Proponents claim that the biochar then sequesters carbon in the soil for hundreds to thousands of years—carbon that would otherwise be released into the air if the organic matter were burned or allowed to decompose.

Consider, for example, the vast swaths of pine trees being killed by mountain pine beetles in the Rocky Mountains. Some, I’m told, are being shipped to Europe to be burned as fuel in coal plants. Others are allowed to decompose, emitting CO2. If, instead, the dead trees were turned into biochar through pyrolysis, and the char was then used in agriculture, substantial amounts of CO2 emissions could be avoided even as renewable energy was created.

The business model for biochar is simple: Buy cheap organic waste, process it and then sell energy and biochar to create two streams of revenue. “If you have $150,000 and 90 days, I can sell you a piece of equipment that will make 50 to 100 pounds of char an hour,” Jonah told me. He says the process will also release about 2 million BTU per hour of producer gas. “We need all the revenue streams we can get, including soil product value, energy value, carbon value, waste mitigation value and more,” he adds. The process, he assures me, requires far less energy than it generates, but the technology for making char isn’t well-developed yet.

James Lovelock, the British scientist who created the Gaia hypothesis, and prominent climate scientist James Hansen are biochar advocates. More than 500 academic papers have been written about biochar, Jonah told me, many of them focusing on its impact on agricultural yields. Research is going on all over the world, including at the USDA’s Agricultural Research Service and at an experimental farm in North Carolina. Here’s a global discussion list with lots of information on biochar research; another good source of information is the International Biochar Initiative, a Washington, D.C.-based nonprofit.

Various companies in Europe, Australia and the U.S. either sell biochar or biochar production units; all are small scale. One of the most intriguing is a startup based in Camarillo, California, called Cool Planet Biofuels that is developing “negative carbon fuels” with biochar as a byproduct. The company website says:

Imagine driving high performance cars and large family safe SUV’s while actually reversing global warming, and without using any foreign oil….the more Negative Carbon “N100″ fuel you use, the more carbon you permanently remove from the atmosphere.

It sounds too good to be true, but investors in Cool Planet Biofuels include Google Ventures, General Electric, NRG Energy and ConocoPhillips.

If they think biochar is worth their attention, it’s probably time for those of us concerned about the climate crisis to take it seriously, too.

[Biochar photo credit: Jonah Levine]