Biochar: Over the past few months, more and more businesses seem to be jumping on carbon offsetting strategies and sustainability initiatives that promise to eliminate carbon emissions. While that’s a good thing, there’s an ancient practice that can do the job in a way that scientists are only now beginning to appreciate.
By the team at 8 Billion Trees, an organization dedicated to the goal of conserving and planting trees
In fact, this one ‘composting’ practice can have a huge impact in the fight against climate change.
So, what is nature’s composting secret?… Biochar.
What is Biochar and How Is It Made?
It is essentially a ‘charcoal material’ made from superheating biomass under oxygen-deficient conditions.
Ancient tribes in the Amazon used to make it for their farms as far back as 2,500 years ago. Evidence of this practice is the discovery of Terra Preta, charcoal-rich soils, in as much as 10 percent of the Amazon rainforest (USBI, 2021).
And although the process of making it has not changed over the years, recently a much deeper appreciation of this ancient practice is growing… thanks to the fact that biochar actually sequesters carbon emissions.
Scientifically speaking, biochar is a charcoal-like by-product of a production process called pyrolysis. While the terms associated with it, such as pyrolysis, appear complex, they are pretty simple and easy to understand in practice. Pyrolysis refers to the practice of decomposing materials at high temperatures in an environment with limited oxygen (Utah State University, 2021). These conditions lead to a chemical change in the material being composted.
In this case, pyrolysis entails collecting organic waste (and other biomass that usually releases methane and other greenhouse gases during normal decomposition) and pilling it up in a place with limited oxygen and high temperatures to allow the residue to decompose into biochar.
The biochar made in this process has unique properties that allow it to be applied in a wide range of soil improvement applications, including carbon sequestration, improving soil water and nutrients adsorption capacity, and suppressing soil-based pathogens (Utah State University, 2021).
Of these myriads of applications, carbon sequestration is by far the most relevant in the current global context. It is therefore not surprising to find countless researchers investigating the potential of biochar in carbon sequestration.
One study notes that crop residues converted into biochar sequester significant volumes of carbon back into the soil, reducing greenhouse emissions (Majumder, Neogi, Dutta, Powel, & Banik, 2019). This ability to sequester carbon is why it is appreciated in climate change circles.
How Does Biochar Eliminate Carbon?
Global warming happens when the rate at which carbon is removed from the atmosphere through plants and other human means is lower than the rate at which carbon is released into the environment. Thus, to reduce global warming, we need to ensure that as much carbon as possible is absorbed from the atmosphere by plants or through human intervention and stored away in the soil.
This is where biochar comes in: By converting plant residue into carbon and storing it into the soil, the product removes carbon from the atmosphere, thereby reducing global warming and combating climate change.
In plants, the carbon cycle starts when trees absorb carbon dioxide from the atmosphere to make their food, a process called photosynthesis. When the plants die, microbes decompose their biomass, which is rich in carbon absorbed from the atmosphere during photosynthesis. Decomposition releases the carbon in the dead plants back into the atmosphere, completing the carbon cycle (Utah State University, 2021).
Simply put-plants extract carbon from the atmosphere when alive, and microbes ensure this carbon is released back to the atmosphere by decomposing the plants when they die (Yoni, 2016). Biochar prevents carbon from being released into the atmosphere by converting the dead plants into carbon-rich, organic, and charcoal-like materials.
What Is the Difference Between Biochar and Charcoal?
It’s important to understand that biochar is very different from charcoal.
When charcoal is produced by burning plant residue slowly at low temperatures, the combustion process is incomplete. It releases about half of the carbon in the plant residue into the atmosphere. In comparison, pyrolysis allows for complete combustion, burning the plant residue into less harmful carbon-rich elements.
Reforestation Combination Delivers One-Two Punch to Climate Change
When biochar is used in conjunction with reforestation offset programs (that restore diverse ecosystems), it can deliver a powerful one-two punch against climate change.
Not only does this help sequester carbon, it becomes a rich source of nutrients for seedlings and other fledgling plants. The reason ancient peoples created “black earth” in the first place was to feed and nurture their gardens. Now, scientists are using this practice to combine it with massive reforestation efforts being carried out in the Amazon rainforest.
By restoring the rainforest areas that have been degraded and cleared over the past few decades, we can help nature revive the carbon sinks she needs to remove greenhouse gases from the atmosphere. And when biochar is included in the equation, the carbon removal potential increases exponentially!
So, the next time you see a new ‘carbon neutral’ initiative, check out the actual program behind it. If reforestation is combined with biochar, then you can be sure the positive benefits to the environment are real.
Works Cited
[1] Majumder, S., Neogi, S., Dutta, T., Powel, M., & Banik, P. (2019). The impact of biochar on soil carbon sequestration: Meta-analytical approach to evaluating environmental and economic advantages. Journal of Environmental Management. doi: https://www.sciencedirect.com/science/article/pii/S0301479719311843
[2] USBI. (2021). Biochar Then & Now. Retrieved October 1, 2021, from USBI: https://biochar-us.org/biochar-then-now
[3] Utah State University. (2021). What is Biochar? Retrieved October 1, 2021, from Extension Utah State University: https://extension.usu.edu/dirtdiggersdigest/2018/what-is-biochar
[4] Yoni, C. (2016, September 30). Biochar and Carbon Sequestration. Retrieved October 1, 2021, from Solution Center for Nutrient Management: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=22224