Cool roofs as a strategy to tackle global warming: economical and technical opportunities

There is a growing consensus within the scientific community that the Earth's climate system is unequivocally warming and it is very likely (according to the formal uncertainty language used in the AR4, the term “very likely” refers to >90% assessed probability of occurrence) due to the increase in anthropogenic greenhouse gas concentrations. Urgent solutions need to be adopted, which are environmentally sustainable, in order to tackle global warming in the short term. At present, the most accredited global warming mitigation methods are represented by the emissions reduction technologies. Such technologies include energy from renewable sources such as solar and wind. A potential alternative is to modify the Earth's albedo by reflective surfaces (pavements and roofs), which are already employed to reduce building energy consumption and to mitigate heat island effects.

In this paper a procedure is proposed which evaluates the influence of changes in the Earth's albedo on the Earth's temperature and, as a consequence, quantifies the high albedo surface size required to compensate or offset global warming from changes in CO₂. Additionally, a technical-economical comparison is carried out here between the proposed albedo system and the main technologies for the production of electric and thermal energy from renewable sources in order to evaluate its effectiveness in terms of cost of carbon dioxide equivalent (CO_2eq) emission reduction.