Demographic Transition, Economic Growth and CO2 Emissions in Colombia: A Calibrated System Dynamics Model for Sustainable Policy Scenarios to 2050

Demographic change, economic growth, and carbon dioxide emissions are strongly interconnected in countries facing long-term sustainability challenges. Colombia is undergoing a demographic transition characterized by changes in population size, age structure, and progressive aging, while also seeking to sustain economic development and reduce environmental pressure. This study develops a calibrated system dynamics model that integrates three interacting modules: demographic structure, economic growth, and CO2 emissions. The demographic module represents the population through three age groups: young population aged 0–14, working-age population aged 15–64, and older population aged 65 and above. The economic module links demographic structure with GDP per capita growth, while the environmental module represents CO2 emissions through a compact Kaya/STIRPAT-type formulation based on population, income, and carbon intensity. The model was calibrated using historical data for Colombia over the period 2000–2023 and projected to 2050 under five alternative economic and decarbonization scenarios. The demographic module reproduced the total population with a mean absolute percentage error of 1.05% and an R2 of 0.977. The economic module achieved a MAPE of 3.06% and an R2 of 0.950 for GDP per capita, while the CO2 module obtained a MAPE of 7.20% and an R2 of 0.741. Scenario results indicate that, under the assumed decarbonization rates, stronger economic growth increases emissions unless accompanied by sufficiently deep carbon-intensity reductions. The proposed framework provides a transparent and policy-oriented tool to evaluate sustainable development pathways in Colombia, while the environmental results should be interpreted as conditional scenario outcomes rather than as a fully identified causal decomposition of emissions drivers.