Greenhouse gas inventory at the sub-national level using the CIRIS tool: A case study in Quang Tri Province, Vietnam

Abstract

This study presents the first comprehensive greenhouse gas (GHG) inventory for Quang Tri Province, Vietnam, using the City Inventory Reporting and Information System (CIRIS) tool at the BASIC level. The inventory covers the stationary energy, transportation, and waste sectors, utilizing 2022 activity data and nationally approved emission factors. Total GHG emissions were estimated at 1,987,208 tons of CO₂ equivalent (CO₂e), with the stationary energy sector contributing the largest share (76.4%), followed by transportation (16.2%) and waste (7.4%). Per capita emissions were 3.1 tons CO₂e, comparable to neighboring provinces. The results highlight key emission sources, including electricity use in residential and industrial buildings and road transport fueled by gasoline and diesel. A mitigation scenario with improved building energy efficiency and rooftop solar systems could cut emissions by approximately 274,000 tons CO₂e annually. Although the CIRIS tool does not require a full uncertainty analysis, this study nevertheless identifies potential data limitations related to informal energy use and under-reported waste flows. It recommends incorporating sensitivity or Monte Carlo simulations in future inventories to quantify uncertainties. By establishing a reliable GHG emissions baseline, this inventory provides critical input for developing targeted climate mitigation strategies and supports Vietnam’s broader commitment to achieving net-zero emissions by 2050.