Biochar Made From Crop Residues Offers a Path To Lower Atmospheric Carbon Dioxide

Climate change is one of the most pressing challenges facing humanity today. Scientists warn that we need to limit the amount of carbon dioxide (CO2) in the atmosphere to avoid the worst impacts of global warming.

But how can we do that when we rely on fossil fuels for energy and agriculture for food?

One possible solution is biochar, a charcoal made from heating discarded organic materials such as crop residues.

Biochar can improve soil fertility and plant growth, while also sequestering carbon in the soil for centuries.

This means that biochar can help reduce greenhouse gas emissions from agriculture and enhance food security at the same time.

A new study, published in the journal GCB Bioenergy, has mapped the global potential of biochar production from crop residues.

The study used a high-resolution dataset of crop residues, which are the parts of plants that are left over after harvesting, such as stalks, leaves, and husks.

The researchers identified areas where crop residues can be sustainably harvested and converted into biochar, without affecting other uses such as livestock feed or soil conservation.

Biochar can offset a significant fraction of global emissions

(Photo : MICHELE SIBILONI/AFP via Getty Images)

The study found that, theoretically, if all the crop residues in the world were turned into biochar, it would sequester about one billion metric tons of carbon per year.

That is equivalent to about 80% of all greenhouse gas emissions from agriculture, or 12% of total global emissions.

However, the study also considered the practical limitations of biochar production, such as the availability of technology, the cost of transportation, and the competing demands for crop residues.

Taking these factors into account, the study estimated that the global biochar production potential is about half of the theoretical maximum, or 510 million metric tons of carbon per year.

Of this amount, about 360 million metric tons would remain sequestered in the soil after 100 years.

The study also ranked the countries by their biochar sequestration potential as a percentage of their current total greenhouse gas emissions.

The results showed that 12 countries have the technical ability to offset more than 20% of their emissions by making biochar from crop residues.

Bhutan topped the list with a potential of 68%, followed by India with 53%, and Nepal with 40%.

Also Read: Biochar Created from Agricultural Waste Adsorbs Wastewater Contaminants

Biochar can benefit farmers and the environment

According to the study's co-lead author, Dominic Woolf, a senior research associate at Cornell University, biochar is one of the few tools that can draw down excess CO2 from the atmosphere at a large scale without competing for land.

Woolf also said that biochar can provide multiple benefits for farmers and the environment.

He explained that biochar can improve soil health, water retention, nutrient cycling, and crop yields. He added that biochar can also reduce soil erosion, fertilizer runoff, and greenhouse gas emissions from soils.

He said that biochar can also help restore degraded lands and increase the resilience of agricultural systems to climate change.

Woolf further stated that biochar production can also create jobs and income for rural communities, especially in developing countries where most of the crop residues are generated.

He also stated that biochar can be produced using simple and low-cost technologies, such as kilns, stoves, or gasifiers, that can be easily adapted to local conditions and preferences.

The study's maps of crop residue production and biochar sequestration can provide valuable insights and support decision-making related to biochar production and investment.

Maps can help identify the most suitable locations, crops, and technologies for biochar production, as well as the potential environmental and social impacts and benefits.

The study's findings highlight the need for more research and development on biochar, as well as more policies and incentives to promote its adoption and use.

According to Woolf, biochar can play a key role in mitigating climate change and achieving the goals of the Paris Agreement, which aims to limit the global temperature rise to well below 2°C above pre-industrial levels.

He concluded that biochar is not a silver bullet, but it is a powerful tool that can complement other mitigation and adaptation strategies.

He said that biochar can help us transition to a low-carbon and climate-resilient future, while also enhancing food security and rural livelihoods.

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