To support China’s ‘dual carbon’ goals in territorial spatial planning, this study by the Shanghai Urban Planning & Design Research Institute advocates for stronger specialized quantitative analysis in territorial spatial planning. It begins by reviewing international and domestic practices on greenhouse gas (GHG) inventories, clarifying key tasks for carbon quantification. The study then establishes a quantitative carbon analysis system based on GHG inventories and proposes a technical approach for multi-scenario carbon emission simulations in territorial spatial planning.