Wrinkles commonly form in geomembrane-based liners system due to exposure to the fluctuations of solar radiation. Generally, air-gaps are present underneath the wrinkles in the geomembrane if devoid of defects. These air-gaps have low thermal conductivity, which may lead to a reduction of the temperature gradient across the liner including the subgrade soil. This paper presents a two-dimension numerical analysis of heat transfer for a geomembrane-geosynthetic clay liner composite liner system. The 2-D numerical analysis of heat transfer shows that the positive effect of the air-gap was minimised due to the lateral heat transfer. Two-dimensional finite element predictions have confirmed that the air-gaps may not significantly reduce the heat transfer towards the subgrade soil.