Dynamics of a coupled socio-environmental model: An application to global CO2 emissions

In this article, a novel coupled socio-environmental model is proposed and analysed using real data. The model is formulated with two interconnected subsystems: a human–environment model that describes the state of forest cover, human population, and atmospheric carbon dioxide (CO2) concentration; and a socio-economic model that represents human behaviour as a dynamical variable. Human behaviour focuses on their opinion about forest conservation, which affects the harvesting rate per unit area. We examine the mathematical model analytically and numerically to gain insight into the dynamics of the coupled system. By plotting the basin of attractions, we show that when an initial abundance of forest cover is small, and there is a low fraction of conservationists, the system eventually stays at a higher density of forest cover and a higher fraction of conservationists. However, for intermediate to high values of initial forest cover, the system stays at a low forest cover and a low fraction of conservationists among people. With an increase in the economic cost, after a certain threshold, we observe that the number of cooperators increases despite the forest cover being very low. Further, the model is validated using yearly data on forest cover and atmospheric CO2 in the period 1990–2016. The fitting to the data is performed using a MATLAB optimization technique, and the quality of the fitting is quantified using accuracy metrics. Numerical simulations using estimated parameters show that increasing forest cover is essential in reducing the CO2 level in the atmosphere. From a policy-making point of view, it is important to increase the proportion of conservationists in the community, which will eventually result in increased forest cover and consequently decrease the burden of atmospheric CO2 concentration.