New Study Maps Nanchang's Carbon Emissions with Unprecedented Detail

Researchers from the Aerospace Information Research Institute (AIR) of the Chinese Academy of Sciences have developed a new method for mapping carbon dioxide (CO₂) emissions across Nanchang, the capital city of Jiangxi province in eastern China, providing a clearer picture of the city's carbon footprint. Their findings were recently published in the International Journal of Digital Earth.

The team combined multiple data sources—including satellite remote sensing imagery, night-time light data, statistical yearbooks, and point-of-interest (POI) information—to build a detailed, high-resolution map of urban CO₂ emissions. Using the inventory method to account for the total annual carbon emissions and then distributing them spatially and temporally by sector, they achieved results with far greater accuracy than existing datasets like Open-source Data Inventory for Anthropogenic CO₂ (ODIAC). The overall margin of error remained within a manageable 13.9%.

The study revealed that the total CO₂ emissions of Nanchang in 2020 were amounted to 20.94 million tonnes. While slightly lower than the previous year, emissions remained high, with the industrial and energy sectors contributing the most. Within industry, the metal smelting industry stood out as the largest source of emissions—highlighting it as a critical target for future reducing emission strategies.

Spatially, the highest emission areas were concentrated in and surrounding Nanchang's core urban zones, where industrial land use is prominent. Monthly trends showed a general increase in emissions over the year, with slight decreases in September and November, and a notable increase in December—largely driven by fluctuations in industrial and energy sector activities.

Distribution of monthly CO₂ emissions  of Nanchang in 2020 with 30-meter resolution. (Image by AIR)

Thanks to the new method, CO₂ emissions were mapped at a fine 30-meter resolution on a monthly basis, offering an unprecedented level of detail. The study's approach not only enhances the ability to monitor urban carbon dynamics but also provides valuable data to policy-makers crafting emission reduction targets and strategies.

This research marks a significant step forward in using multi-source data to better understand and manage urban carbon emissions.