Plants That Feed Livestock Could Be Key To Climate Change Mitigation

Jacobo Arango, an environmental biologist at the Tropical Forages Program at the Alliance of Bioversity and CIAT and an author of the mitigation chapter of the Intergovernmental Panel on Climate Change (IPCC) report released on April 4, 2022, said it was encouraging to see in the report that some countries are on track to meet their commitments, but unfortunately, the world is not on track to meet the 1.5-degree warming scenario.

"The agriculture and land-use sector (which includes forestry) has a really invigorating role with this IPCC report," he said. "It's not enough only to lower emissions, we also need to actively remove carbon from the atmosphere."

While the popular conception of carbon capture and storage is the injection of carbon dioxide gas deep underground, Arango says that deep-rooted plants, including those used in livestock grazing, could store carbon 2-3 meters underground as soil organic matter (soil carbon).

"If you use the right plants, with a long root system, they can transfer the carbon from the atmosphere into the deep soil layers," he said, "Instead of big fancy machines taking carbon out of the atmosphere and injecting it into rock formations, agriculture does that naturally with plants, along with higher food production and other environmental benefits, such as water and biodiversity conservation."

Arango explained that plants usually put carbon in shallow soil layers (the first 30 centimeters). However, this carbon is more susceptible to return back to the atmosphere by the soil respiration process, while soil carbon deposited deeper by long roots has a higher chance to be stored for much longer.

Ngonidzashe Chirinda, an assistant Professor of Sustainable Tropical Agriculture at Morocco's Mohammed VI Polytechnic University and former IPCC author, says the 30-centimeter depth used in the IPCC greenhouse gas inventory guidelines underestimates carbon uptake linked to tropical forages that develop roots to over 1 meter in depth.

"Few countries currently report soil carbon's climate change mitigation contribution in their national greenhouse gas inventories and the lack of accounting means a vital carbon sink is missed," Chirinda said, adding that countries need to accurately report the carbon added to the soil through mitigation actions such as adopting deep-rooted tropical forages (grasses and other plants grown as food for livestock).