Intensifying farm machinery emissions might impede China's aspiration for net-zero carbon emissions.
China's agricultural mechanization has been on the rise, leading to a significant increase in carbon emissions from machinery. According to a recent study published in Nature Food, carbon dioxide (CO2) emissions from agricultural machinery in China have increased approximately seven-fold since 1985, reaching nearly 160 million tonnes of CO2 (MtCO2) in 2020.
The expansion of agricultural mechanization supports short-run agricultural economic growth, but it risks raising emissions if it relies on traditional fossil-fuel machinery. The study reveals that diesel fuel usage for machinery is a major contributor to agricultural emissions, alongside other sources like fertilizers, pesticides, and livestock gases.
The increase in farm equipment CO2 emissions can be attributed to several factors. The increasing level of mechanisation dominates the change, responsible for a 100% increase in emissions over 1985-2000. Population growth was a large driver of increasing farm equipment emissions over the early part of the study period, but has been less of a factor since 2000.
In the longer term, renewable energy sources, as well as green hydrogen, have the largest mitigation potential. Effective mitigation of these emissions will require different strategies in the short- and long-term future. Near-term availability suggests that biofuels and natural gas will play an important role over the coming decade.
The researchers break the emissions down to the province level, finding a large range of agricultural machinery emissions among provinces. Five provinces in eastern and north-eastern China - Shandong, Henan, Heilongjiang, Hebei and Anhui - account for more than 40% of agricultural machinery emissions.
The emissions contribution of large tractors has increased steadily since 2005, attributed to a series of policies to promote large-scale machinery. However, the emissions intensity uniformly acted to decrease emissions, while "tillage pressure" increased emissions early on in the study period, but decreased emissions since 2000.
The study highlights that unabated continued growth of agricultural mechanisation could compromise China's efforts to achieve its "dual-carbon" goals. By 2050, under a pathway to China's 2060 net-zero goal, increased mechanization of agriculture could account for 21% of China's total emissions.
Ritchie is skeptical that the relative contributions of agricultural machinery will be as high as 20% in 2050, suggesting that progress in reducing emissions from other sectors may also play a role. The researchers calculate that CO2 emissions from farm equipment have grown, on average, by nearly 6% annually since 1985.
Mitigation strategies to address emissions from agricultural mechanization include transitioning to electric or hydrogen-powered machinery, enhancing machinery fuel efficiency and operational optimization, integrating carbon capture and storage (CCUS) technologies, increasing use of clean energy technologies in agricultural activities, and improving agricultural practices reducing overall emissions related to farming inputs and operations.
In summary, increased mechanization in Chinese agriculture will lead to higher carbon emissions from machinery by 2050 under current trends. These emissions can be effectively mitigated through cleaner machinery technologies, enhanced efficiency, and integration of carbon capture and renewable energy solutions. Such combined approaches are vital to align agricultural mechanization growth with China’s climate goals.
Under current policies, China aims to achieve comprehensive mechanisation in major crop production processes by 2035. Food systems are responsible for around one-third of human-driven greenhouse gas emissions. The study relies on data from the China Statistical Yearbook to calculate machinery-related emissions of CO2, fine particulate matter (PM2.5), nitrogen oxides (NOx) and total hydrocarbons (THC).
- China's push for agricultural mechanization, despite supporting short-term economic growth, risks exacerbating carbon emissions if it relies on fossil-fuel machinery, as carbon dioxide (CO2) emissions from such machinery have increased significantly since 1985.
- The researchers suggest that renewable energy sources and green hydrogen could have the largest mitigation potential in the long term for agricultural emissions.
- The study demonstrates that carbon emissions from agricultural machinery in China are vast, with five provinces in eastern and north-eastern China - Shandong, Henan, Heilongjiang, Hebei, and Anhui - accounting for more than 40% of these emissions.
- The emissions contribution of large tractors has increased steadily since 2005, due to policies promoting large-scale machinery.
- Current policies in China intend to achieve comprehensive mechanization in major crop production processes by 2035, yet the study underscores the importance of aligning agricultural mechanization growth with China’s climate goals.
- As food systems are responsible for around one-third of human-driven greenhouse gas emissions, it is crucial to address emissions from agricultural mechanization through cleaner machinery technologies, enhanced efficiency, and integration of carbon capture and renewable energy solutions.
- The researchers calculated that CO2 emissions from farm equipment have grown, on average, by nearly 6% annually since 1985, emphasizing the need for immediate action to curb agricultural emissions and meet China's "dual-carbon" goals and net-zero emission ambitions by 2060.
