Discover CALS

See how our current work and research is bringing new thinking and new solutions to some of today's biggest challenges.

By Johannes Lehmann, edited by Krisy Gashler
  • Department of Global Development
  • School of Integrative Plant Science
  • Agriculture
  • Climate Change
  • Soil

Johannes Lehmann, the Liberty Hyde Bailey Professor in the School of Integrative Plant Science and the Department of Global Development, is at the forefront of research on biochar, a form of charcoal created by heating biomass (like manure or food processing waste) at moderate temperatures and without oxygen – a process called pyrolysis. Biochar systems can help reduce greenhouse gas emissions, pull carbon from the atmosphere and improve soil health.

You started working with biochar in the late 1990s; what have you learned about how it benefits people and the planet?
Johannes Lehmann standing in Cornell's pyrolysis facility
Lehmann. Photo by Allison Usavage

The way charring fundamentally changes the composition of organic matter dramatically reduces the emissions of greenhouse gases that would otherwise have been emitted from residues that we apply to soil. But biochar also interacts with soil-based organisms to reduce emissions of carbon dioxide and nitrous oxide from existing soil organic matter. Biochar increases average crop yields as much as inorganic fertilizer, but even more than inorganic fertilizers where soils are less responsive to nutrient additions. But what may turn out to be the most critical game changer is the way biochar has altered the conversation about soils, systems thinking, and innovation: the new perspective has attracted students into the field, taught us that we had to use a life-cycle perspective in understanding soil effects on climate, and made abundantly clear that new ideas are lurking everywhere.

What is the most pressing need for additional research on biochar?

Much remains to be done on the science side, but the most important action right now is shaping policy and financial instruments: Developing carbon markets and the regulatory framework to allow industry adoption is key to safely scaling up the climate benefits of biochar.

There has not been much scale-up as yet, which is reasonable – we can’t expect the technology development and the scale-up to happen in the same decade – but we also can’t afford to wait any longer to find out what the actual potential is. Modern photovoltaic and wind energy technology existed in the 1950s, but it took another 50 years to see real scale-up and adoption of those technologies. We need to move much more quickly to position biochar to achieve its sustainable potential to help mitigate catastrophic climate impacts. After we exhaust all options to reduce existing emissions, we have few near-term tools to withdraw atmospheric carbon dioxide in our global tool box, and we cannot afford to not explore them all.

With COP26 happening right now, what message do you want to share with policymakers and the public?

There needs to be a handshake between science and implementation through public-private partnerships to create living-learning laboratories. Thus far, our research on biochar has been limited to small companies, individual farms and small research plots. To really understand the costs and benefits of biochar, we need field-scale, landscape-scale, global-scale studies, and we can’t do that alone as academics; that requires farmers, industry and government working cooperatively to implement this technology.

One good example: The New York State Energy Research and Development Authority (NYSERDA) granted $1 million to put a biochar pyrolysis unit on a New York dairy farm. When it’s completed next year, it’ll be the first New York dairy farm with such a unit and one of only a handful in the United States. There are so many other potential partners, though: wastewater treatment plants, dairy and other food processors, even grocery stores – basically, any entity that produces or manages biological waste is a potential source of biochar and, therefore, a source of climate change mitigation.


Keep Exploring

Scott Cosseboom works at the Cornell Hudson Valley Research Laboratory


The Cornell Hudson Valley Research Laboratory (CHVRL)’s new plant pathologist will focus on sustainable disease management in specialty crops, which is critical to New York’s agriculture industry. Scott Cosseboom started as senior research...
  • Cornell AgriTech
  • School of Integrative Plant Science
  • Plant Pathology and Plant-Microbe Biology Section
agricultural fields


The findings The study identifies stark discrepancies in food production data worldwide, notably within livestock, fisheries, and aquaculture sectors. These sectors experience pronounced data gaps, especially at national and local levels, due to...
  • Cornell Atkinson
  • Department of Global Development
  • Agriculture