Can Biochar Solve Climate Change?

Is biochar the answer to reducing the causes of climate change? Depends on who you ask. A new study from the University of Sydney shows that biochar could reduce nitrous oxide emissions by more than 70% in addition to sequestering tons of carbon dioxide.

Biochar has a bit of a cult following. Advocates from Professor Johannes Lehmann at Cornell to more celebrity personalities like Richard Branson endorse biochar as a solution to mitigate climate change. Yet it remains somewhat of an enigma outside of its supporters.

So what is biochar exactly? You might be more familiar with its closely related cousin, charcoal. The main difference is the function. Charcoal is great if you’re looking to have a cookout. Biochar is great if you’re looking to mitigate climate change and increase soil fertility.

It’s created by cooking organic matter such as plant or animal waste in the absence of oxygen. The process has been around for thousands of years and has been used in the Amazon to improve soils for agriculture. Nowadays, interest in biochar stems from its ability to sequester carbon. By burning it in the absence of oxygen, carbon is sequestered in a more stable state. One study estimates that biochar projects could sequester up to 900 million metric tons of carbon annually. That’s about 20% of current carbon dioxide emissions.

The recent study about biochar adds to the allure of it as a climate change solution. It’s not just good at sequestering carbon: it also reduces nitrous oxide emissions, another greenhouse gas. Nitrous oxide is a potent warming agent that’s 310 times more powerful than carbon dioxide. Both natural and human processes related to agriculture produce nitrous oxide.

The study from the University of Sydney is the first of it’s kind to examine the seasonal potential of biochar. The researchers simulated real soil conditions. This provides a better perspective on how biochar would work in the field. What they found was that initially, soils with biochar fixed less nitrous oxide than the control samples. After three months, though, the biochar soils reduced nitrous oxide emissions by 73% compared to the control plots.

As an added bonus, biochar-treated soils also helped prevent ammonia and nitrogen from leaching into water supplies. Despite all these benefits, biochar still plays a minor role in efforts to confront climate change. The main challenges are scaling up the processes to an industrial level and other, possible averse side effects for local soils, particularly outside the tropics.

Even if biochar is scaled up to make an impact on the causes of climate change, it’s no panacea. Rather, it could be one of a number of climate change solutions.

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