A behavioural–environmental model to study the impact of climate change denial on environmental degradation

Climate change is the biggest global threat facing humanity in the coming decades. The scientific community agrees that human activity has been responsible for virtually all global heating over the past two centuries, emphasising the urgent need for the collective adoption of environmentally responsible behaviour. In this paper, we propose a novel behavioural-environmental mathematical model that explores the complex and nonlinear co-evolution of human environmental behaviour and anthropogenic environmental degradation. Our model considers a population of individuals, which includes climate change deniers, interacting on a polarised population structure. In addition to addressing climate change denial, our framework captures other key aspects of the climate crisis by modelling human behaviour through a social learning mechanism inspired by game theory that accounts for social influence, environmental sensitivity, government policies, and the costs associated with environmental-friendly actions. By employing a mean-field approach in the limit of large populations, we derive an analytically tractable set of equations that is easy to simulate. By analysing this set of equations, we shed light into the emergent behaviour of the system. Under reasonable assumptions, we demonstrate global convergence to a periodic solution, with oscillations influenced by climate change deniers and polarisation in a non-trivial manner, as discussed via a campaign of numerical simulations.