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Human beings almost entirely rely on soil for producing a growing quantity of food and this has caused massive emissions of greenhouse gases from soil, scientists have established in a new research.
In a first-of-its-kind study, scientists revealed that soil-based emissions contribute to around 15 per cent of the global increase in climate warming. These emissions, primarily in the form of carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4), were largely driven by agricultural practices, land-use changes and the growing global demand for food.
While soil has been regarded as a reservoir for carbon, the authors said that its contribution to greenhouse gas emissions has created a “wicked problem” of how to continue increasing food production from soil while also decreasing emissions.
The research titled Soil is a major contributor to global greenhouse gas emissions and climate change was done by scientists from the School of Agriculture and Food Sustainability, the University of Queensland, Australia, Institute of Biological and Environmental Sciences, University of Aberdeen, Scotland, United Kingdom and Nanjing Agricultural University, China.
It was based on an analysis of existing data for key greenhouse gases and was published on December 6, 2024 in the journal Soil.
Providing a detailed breakdown of how soil contributes to global warming, the research found that CO2, which accounts for 74 per cent of soil-derived warming, was the most dominant greenhouse gas emitted from soil, followed by N2O (17 per cent) and CH4 (9 per cent).
Together, these emissions posed a significant challenge in the effort to meet international climate targets, including limiting global warming to 1.5-2°C above pre-industrial levels.
This creates an even more complex problem when the United Nation’s Food and Agriculture Organization (FAO) estimated that food production to support global population will need 165-600 million more hectares of land for crop and livestock production to meet demand by 2050 is considered.
The release of CO2 from the soil due to the loss of soil organic compound (SOC) following land use change has had the largest adverse effect on atmospheric greenhouse gas concentrations, contributing 11 per cent to the total increase in warming due to well-mixed greenhouse gases.
Much of this CO2 release from soil due to land use change is historical, having peaked between 1800 and 1900, with current emissions of CO2 from the loss of SOC being dominated by the ongoing land use change in “new-world countries such as Brazil and Argentina”.
“…despite the ongoing critical role of soil as a sink for greenhouse gases, it is also imperative to quantify how the anthropogenic use of soil has also increased atmospheric emissions of greenhouse gases from soil. This is because the net anthropogenic increase in emissions from soil, together with emissions of greenhouse gases from other sources such as the burning of fossil fuels, also contributes to global warming and climate change,” the research said.
The authors called for an urgent need to prevent further land use change, including for biofuel production and to limit the release of CO2 that results from the loss of SOC.
Other actions included a need to develop strategies to increase nitrogen fertiliser efficiency in order to reduce nitrous oxide emissions, to decrease methane from rice paddies, and to ensure that the widespread thawing of permafrost is avoided.