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Addressing soil pollution and achieving global carbon neutrality requires low carbon remediation practices. When selecting the optimal remediation techniques, a comprehensive model is required to assess the environmental and economic impacts accurately. In the present study, a spatial three-tier framework that combines process cycle assessment (PLCA), Input output analysis (IOA) and Multi-Regional Input Output analysis (MRIOA) has been used to evaluate the greenhouse gas (GHG) emissions of three commonly used remediation alternatives at a contaminated site in Hubei Province, China, as well as the indirect GHG emissions of the industry chain at provincial and national scale. The three remediation techniques were coprocessing in a cement kiln (CCK), ex-situ solidification and stabilization (ESS), and soil washing (SLW). Using a tiered hybrid life cycle assessment (THLCA) approach, the results demonstrated the importance of including off-site emissions in life cycle assessments. It was found that CCK had the lowest total GHG emissions among the three alternatives. Off-site greenhouse gas (GHG) emissions associated with three soil remediation alternatives vary significantly, with CCK exhibiting the lowest levels and ESS the highest. Soil remediation emissions mainly affected Hubei Province, with varying spillover effects on other regions, such as Inner Mongolia, Shanxi, Liaoning, and Gansu, which supplied material resources and power supply for the soil remediation project. The production and supply of electricity and heat (PSE) sector contributed the most to off-site emissions, accounting for 56.05%, 67.76%, and 67.30% of total emissions for CCK, ESS, and SLW, respectively. Overall, the present study provides fresh insights to support a more holistic low-carbon assessment of soil remediation options. [Display omitted] • Low GHG emissions were considered in selecting optimal soil remediation strategies. • Three-tier spatial GHG emission model was adopted to explain remediation impacts. • CCK with the lowest GHG emissions was recommended for soil remediation. [ABSTRACT FROM AUTHOR]