Performance of green roof systems

Global average temperatures have continued to rise as a result of global warming in the past two decades (EPA, nd; Watson et al., 2001). Climate change increases the frequency and intensity of higher temperatures and heat waves. The higher temperatures increase the demand for energy use for air conditioning, increasing greenhouse gas emissions and the levels of other pollutants. This process results in a positive feedback system, whereby the short-term adaptations to a warmer climate, such as increased use of air conditioning, serve to perpetuate global warming and exacerbate other air quality problems. Since high summer temperatures bring about many environmental and health problems (McCarthy et al., 2001), reducing these temperatures has become a major concern for many major metropolitan cities in North America.Au cours des deux derni\ue8res d\ue9cennies, les moyennes des temp\ue9ratures \ue0 l?\ue9chelle du globe n?ont cess\ue9 d?augmenter en cons\ue9quence du r\ue9chauffement de la plan\ue8te (EPA, Dakota du Nord; Watson et coll., 2001). Le changement climatique accro\ueet la fr\ue9quence et l?intensit\ue9 des hautes temp\ue9ratures et des vagues de chaleur. Les temp\ue9ratures \ue9lev\ue9es font augmenter la consommation d?\ue9nergie pour la climatisation, les \ue9missions de gaz \ue0 effet de serre et aussi les niveaux d?autres agents polluants. Ce processus entra\ueene la cr\ue9ation d?un syst\ue8me de r\ue9troactivation : les moyens d?adaptation \ue0 court terme \ue0 un climat plus chaud tels que l?utilisation accrue des climatiseurs viennent contribuer en fait au r\ue9chauffement de la plan\ue8te et exacerber d?autres d\ue9ficiences de la qualit\ue9 de l?air. Comme les temp\ue9ratures \ue9lev\ue9es en \ue9t\ue9 entra\ueenent de nombreux probl\ue8mes environnementaux et de sant\ue9 (McCarthy et coll., 2001), la r\ue9duction de ces temp\ue9ratures est devenue une question imp\ue9rative pour plusieurs grandes m\ue9tropoles d?Am\ue9rique du Nord.Peer reviewed: YesNRC publication: Ye