Four pathways towards carbon neutrality by controlling net greenhouse gas emissions in Chinese cropland

Abstract

Decreasing greenhouse gas (GHG) emissions and enhancing soil carbon (C) sequestration in cropland are necessary to achieve carbon neutrality at national scale. However, feasible pathways to mitigate net GHG emissions in Chinese cropland while ensuring food security remain poorly defined. Here, we establish a comprehensive assessment framework and propose four mitigation pathways. In the baseline scenario, GHG emissions are projected to be 439.9–443.5 Tg CO2e after 2030. Through simultaneously implementing the four pathways of recycling organic waste, improving nitrogen (N) use efficiency, optimizing water management and strictly controlling N input/surplus, cropland GHG emissions are projected to decline from 433.5 Tg CO2e in 2020 to 389.7 Tg CO2e (-11.4%) in 2030 and 338.3 Tg CO2e (-23.7%) in 2060. The accumulated quantity of soil C sequestered would increase by 33.9% from 2021 to 2060. Considering both GHG emission reduction and increment of soil C stocks, the net GHG reduction rate would be 37.4% and 41.2% in 2030 and 2060, respectively. These pathways help transition crop production to a low-carbon and high-efficiency pattern while maintaining or increasing crop yield. As the first attempt, our study provides a scientific reference for approaches to accelerate GHG mitigation and soil C sequestration in Chinese cropland. This type of integrated assessment has potential to support policy-making in developing countries aimed at finding an equitable balance between crop production and environmental benefits.