Thermal Impedance Analysis of Possible Influence of Concrete Structures on Earth’s Energy Balance and Global Warming

Abstract

A possible contribution of ever increasing number of concrete structures to the delicate energy balance of the Earth and consequent rise in its surface temperature are presented and discussed. Concrete has much higher thermal effusivity (or low thermal impedance) and much lower specific heat capacity compared to vegetation. As a consequence of these, vegetation functions as heat sink while concrete structures act as heat sources. Due to high thermal mass of concrete, it takes a long time for heated concrete structures to cool down to the ambient environmental temperature, making it embedded heat source on the surface of the Earth. This phenomenon gives rise to ill-effects such as the urban heat island effect in metropolitan areas. Replacement of more and more vegetation with concrete structures may result in a possible imbalance of the Earth’s energy balance and a possible rise in the overall surface temperature of the Earth, or global warming in the long run. Though it is difficult to isolate the temperature rise due to this effect, it is argued that it possibly has a contribution to global warming. An analysis of the issue based on numerical values of the thermal properties of materials abundant on the surface of the Earth, and the time dependence of temperatures inside a concrete building are presented and discussed.