Cities occupy just a small fraction of Earth's land, but they act as the planet's massive carbon engines, pumping out the lion's share of global CO2 emissions. To stop climate change, we first have to measure it accurately—street by street and chimney by chimney. A comprehensive new review published in Carbon Research takes a deep dive into the sophisticated networks designed to "sniff out" these emissions, highlighting both the technological triumphs and the massive gaps still remaining in our global monitoring net.
Leading the charge is Professor Gan Zhang from the State Key Laboratory of Advanced Environmental Technology at the Guangzhou Institute of Geochemistry, Chinese Academy of Sciences. Along with an international perspective, the study provides a critical look at how high-precision atmospheric observations are becoming the gold standard for tracking whether climate policies are actually working in real-time.
The research synthesizes data from ten major long-term monitoring networks and over 20 cities worldwide. It highlights a stark geographical divide: while North America, Western Europe, and East Asia are becoming "smart-monitored" hubs, vast regions across Africa, South America, and South Asia remain almost invisible to high-precision carbon tracking.
"We cannot manage what we do not measure," says Professor Gan Zhang. "By integrating top-down atmospheric measurements with traditional bottom-up inventories, we can create a transparent, evidence-based framework for carbon neutrality. Our work at the Chinese Academy of Sciences is focused on refining these tools to meet the complex challenges of modern, sprawling urban landscapes."
Critical Insights from the Review:
- The China Phenomenon: The study underscores China's rapid leap forward in urban carbon monitoring, providing a template for how emerging economies can scale up climate technology.
- Urban Shifting: Researchers identified a new challenge in "industrial relocation." As factories move away from city centers, monitoring networks must adapt to a widening gap between where people live and where carbon is actually released.
- The Biogenic Blur: Distinguishing between carbon from fossil fuels and carbon from natural "breathing" ecosystems (plants and soil) remains a major technical hurdle that requires advanced network designs to solve.
- Customized Blueprints: One size does not fit all. The review argues that a megacity in a desert requires a completely different sensor layout than a medium-sized city in a forest.
This review serves as a strategic manual for policymakers and scientists alike. It calls for a global push toward technology transfer and data-sharing, ensuring that cities in the Global South have the same tools to fight climate change as those in the North.
By bridging the gap between atmospheric science and urban planning, Professor Gan Zhang and the team at the Guangzhou Institute of Geochemistry are helping to ensure that the cities of tomorrow are not just centers of commerce, but leaders in environmental stewardship.
Corresponding Author:
Gan Zhang
State Key Laboratory of Advanced Environmental Technology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China.
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Journal reference: Li, J., Li, P., Han, P. et al. Advances in the design of urban CO2 emission monitoring networks: a review. Carbon Res. 5, 3 (2026).
https://doi.org/10.1007/s44246-025-00239-z
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About Carbon Research
The journal Carbon Research is an international multidisciplinary platform for communicating advances in fundamental and applied research on natural and engineered carbonaceous materials that are associated with ecological and environmental functions, energy generation, and global change. It is a fully Open Access (OA) journal and the Article Publishing Charges (APC) are waived until Dec 31, 2025. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of carbon functions around the world to deliver findings from this rapidly expanding field of science. The journal is currently indexed by Scopus and Ei Compendex, and as of June 2025, the dynamic CiteScore value is 15.4.
