Human activities profoundly influence environments, generating multiple impacts and risks at diverse spatial and temporal scales. Among these, climate change—driven primarily by rising atmospheric CO₂—represents one of the most critical global challenges.

The Mediterranean region, already affected by droughts, wildfires, and biodiversity loss, is particularly sensitive to changes in carbon fluxes owing to its dense urbanization and active volcanic zones. Anthropogenic CO₂ emissions dominate the global carbon budget, whereas volcanic degassing contributes a minor but persistent fraction that can locally alter atmospheric composition on short timescales. Disentangling these overlapping sources is essential for accurate environmental impact and risk assessments.

This study presents isotopic investigations of carbon and oxygen in CO₂ (δ¹³C and δ¹⁸O) to distinguish anthropogenic from volcanic and biogenic emissions in both urbanized and remote areas of the Mediterranean region. Data collected within the Atmospheric Carbon and Oxygen Laboratory (ACO-Lab) and its Gradient in Atmospheric Urban Dome (GraDo) side project—coordinated by the Istituto Nazionale di Geofisica e Vulcanologia—reveal that carbon isotope ratios reveal the origin of CO₂ emissions. In contrast, oxygen isotope variations display moderate dependence on altitude and vegetation cover.

These results highlight the value of isotopic fingerprinting as a suitable monitoring tool for assessing the environmental impact of CO₂ emissions, improving our ability to quantify anthropogenic contributions, investigating dependencies among biogenic cycles, and supporting strategies for mitigation and sustainable urban management in regions influenced by a combination of natural degassing and anthropogenic pollution.