A 1% increase in soil carbon sequestration on cropland and pasture could provide a decade’s worth of emissions reductions, keeping the world on track to meet its 2030 climate obligations.
That’s according to research led by Jacqueline McGlade at the Institute for Global Prosperity, University College London, which used thousands of soil profiles from the World Soil Information System to estimate the soil organic carbon (SOC) potential of 2,352 million hectares of agricultural land.
McGlade found that the 1% average increase across cropland, pasture and irrigated fields would result in 311 gigatonnes CO2 equivalent (GtCO2e) of carbon sequestration, representing over a decade of the emissions cuts required to keep global temperature rises under 2°C or 1.5°C, or else on a Net Zero pathway.
The work aimed to address the fact that fixed soil carbon targets have yet to be attached to global climate agreements. With farmers and land managers regularly testing their soil, making them familiar with its organic carbon content, it would make a 1% target easy to understand, she argued.
“Soil carbon sequestration presents an opportunity to enhance carbon removals across the world and at the same time address critical issues such as food security and enhancing resilience to extreme climate-related events,” McGlade wrote.
Proven approaches
Addressing scepticism over being able to sequester carbon over the long term in soils, she argued that overlooking the opportunity “does not make sense,” faced with a need to pursue as many varied emissions reduction strategies as possible.
“The focus should therefore be on supporting activities to improve soil carbon storage as a first stage towards increasing the long-term sequestration trajectory of the terrestrial carbon sink, even in marginal lands in arid areas or where there are ancient soils with very low levels of soil carbon,” she continued.
“While this may be challenging, reports of long-term increases in soil organic carbon across a wide range of farms globally indicate that certain practices are succeeding.”
Supporting this, she pointed to novel grazing practices, regenerative agriculture and pasture restoration as examples of proven routes to achieving SOC improvements.
Financial support will be needed to help the poorest farmers adopt soil-friendly farming practices, she stressed, but they would expect to see benefits from improved food security, while helping agriculture shift from being a major cause of climate change to part of the solution.