Dubai hosted the COP28 in early December 2023. Ironically, the rich city which relies heavily on oil and gas, with no sign of solar panels, produced a fossil fuel phase-out agreement. The agreement commits countries to transition away from fossil fuels in energy systems, in a just, orderly and equitable manner, to achieve net-zero emissions by 2050. While some argue more needs to be done, this was the first time that the COP explicitly addressed the need to end the use of fossil fuels.
Another main outcome for agriculture was the COP28 UAE Declaration on Sustainable Agriculture, Resilient Food Systems, and Climate Action. Agriculture is intimately linked to climate change, both as a source of greenhouse gas emissions and an industry facing significant disruptions due to shifting climate patterns. The declaration garnered substantial attention, signed by 159 nations, representing nearly 80% of the world’s land area, including major food-producing nations like Australia, Brazil, China, the European Union, Russia, Indonesia, and the United States. There was a strong presence of agriculture and food, with several pavillions and side events decicated to soil.
The core of the Sutainable Agriculture declaration is on strategies to bolster climate resilience for farmers and food producers. Key components include providing financial support, enhancing infrastructure, and fostering innovations in agriculture to ensure food security, particularly for vulnerable populations. Integrated water management was also a significant aspect.
Furthermore, the declaration stressed the need to promote sustainable agricultural practices, including measures to improve soil health, conserve and restore land and natural ecosystems, and increase biodiversity. Shifting toward sustainable production and consumption practices was emphasized as a crucial step in reducing the environmental footprint of agriculture and food systems. Reducing food loss and waste emerged as a priority.
Agriculture and Net Zero
Given agriculture’s significant contribution to emissions, continuing with business as usual is no longer tenable. Intensive agriculture exacerbates climate change, impacting crop yields and causing farmers to grapple with rising temperatures, intensified extreme events like droughts, fires, and floods.
Agriculture, however, holds the potential to be part of the solution. While the Sustainable Agriculture declaration lacks targets and relies on locally tailored solutions, it underscores the need for change. Soil health is mentioned for the first time in the COP declaration. A healthy soil provides multiple functions, including biomass production, carbon regulation, habitat for biodiversity, nutrient cycling, and water cycling. Boosting soil health is essential for the well-being of both humans and the planet.
Soil organic carbon (SOC) sequestration, which involves storing carbon in soil to mitigate climate change, has been considered a cost-effective climate mitigation approach with multiple benefits. SOC also enhances soil health and is recognized by governments as a low-emission priority technology.
However recent research suggests that SOC sequestration potential on global croplands is limited and equivalent to only a few years of annual fossil fuel emissions. This raises doubts about its effectiveness in mitigating climate change. The premise of SOC sequestration is to recover historical losses caused by intensive agriculture, which has depleted soil carbon stocks. Yet, ongoing intensive agriculture continues to emit greenhouse gases (GHGs).
In the past decade, soil-related GHG emissions have been substantial. Our global modelling approach has shown that approximately 1.9–2.4 Pg of SOC are lost annually due to land use changes, equivalent to 7.9 Pg of CO2 emissions. Nitrous oxide emissions from soil amounted to 1.4 Pg of CO2 emissions per year due to agricultural pratices. And methane emissions from rice fields totaled 0.76 Pg of CO2 emissions per year. Combined, these soil-based emissions account for 25% of current fossil fuel emissions.
Continual emissions of carbon and greenhouse gases from soils pose a significant obstacle to climate security. These emissions contribute to the worsening of climate change, highlighting the urgency of transitioning to more sustainable agricultural practices that minimise greenhouse gas release. These also pose problems for agriculture to reach net zero. Rather than solely depending on soil organic carbon (SOC) to compensate for emissions, our primary focus should be averting unnecessary losses through improved land management.
Healthy soil for a healthy planet
The ongoing degradation of soil, particularly due to intensive agricultural practices, has significant implications for human health. Intensive agriculture is already diminishing soil’s inherent production capacity. For instance, the loss of soil organic matter reduces biomass production, and restoring soil organic matter could increase crop yields significantly.
Additionally, soil degradation contributes to climate change and biodiversity loss, indirectly impacting human health. Climate change has already decreased crop production and is expected to reduce global food availability further by 2050. Loss of soil biodiversity in intensive agricultural systems hampers overall soil productivity, which is crucial for disease control, nutrient cycling, and fertility. Increasing soil biodiversity complexity enhances resilience, nutrient use efficiency, and crop yields.
The ability to produce sufficient food in the long term depends on curbing soil degradation and preserving soil health. Soil degradation not only affects food production but also contributes to social and political instability.
Increasing SOC has multiple benefits, including enhancing drought resilience, improving soil fertility, boosting crop productivity, and contributing to radiative cooling. Restoring soil functions by increasing SOC can collectively help mitigate global challenges.
While fundamental soil carbon theories and models have been valuable, they have not kept up with the evolving focus on soil multifunctionality and the need to manage landscapes to increase multiple soil functions. A comprehensive theoretical framework is needed to understand how minerals in soil interact with SOC, plants, and microbes under various conditions and land use systems and serve multiple functions beneficial to human beings.
Advancements in theoretical knowledge will lead to novel technologies for measuring SOC and manipulating the soil environment to enhance its function. These technologies can improve food production systems, provide ecosystem services, and offer rapid and cost-effective ways to measure soil carbon functions.
Increasing SOC is not solely for climate change mitigation but is crucial for planetary functioning to support human societies and address a range of global challenges.
References
Minasny, B., McBratney, A.B., Arrouays, D., Chabbi, A., Field, D.J., Kopittke, P.M., Morgan, C.L., Padarian, J. and Rumpel, C., 2023. Soil Carbon Sequestration: Much More Than a Climate Solution. Environmental Science & Technology. https://pubs.acs.org/doi/10.1021/acs.est.3c07312
Padarian, J., Stockmann, U., Minasny, B. and McBratney, A.B., 2022. Monitoring changes in global soil organic carbon stocks from space. Remote Sensing of Environment, 281, p.113260.
Display at the Ukranian pavillion at COP28.
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