Agricultural machinery could contribute 20% of total carbon and air pollutant emissions by 2050 and compromise carbon neutrality targets in China.

Agricultural mechanization has benefitted food security in China, but carbon dioxide (CO2) and air pollutant emissions from fuel combustion are often overlooked. Here we show that emissions of CO2 and air pollutants from agricultural machinery increased nearly sevenfold and four- to sevenfold, respectively, during 1985-2020, driven largely by rapid advancement in the mechanization level. If unabated, annual emissions of CO2, PM2.5 and NOx from agricultural machinery in 2050 could reach 213.6 Mt, 55.4 Gg and 902.8 Gg, contributing ~21%, ~4% and ~17% of China's total emissions under a dual-carbon goal scenario, respectively. However, adoption of renewable energy sources could mitigate 65-70% of these emissions. Our study highlights that China's agricultural machinery could become a large source of emissions that-without mitigation-may hinder China's carbon neutrality targets and degrade air quality.