# Are Green Buildings an Indicator of Sustainable Development?
## 1 Introduction
In 2018, the United Nations estimated that the share of the world's population living in urban areas was 55%, a proportion expected to increase up to 68% by 2050 [12]. Since the construction rate of buildings and cities keeps steadily growing, the overall quality of buildings must be improved in order to mitigate climate change, whose main driving force is unanimously recognised to be human activity [13]. Buildings need to reduce their environmental footprint during their entire lifecycle, from the design/construction to the operation and dismantling, and the only way to achieve this challenging target is through a coordinated global effort. In 2020, the European Commission stated that buildings in the EU were responsible for 36% of GHG emissions [14], which mainly stem from construction, usage, renovation  
Figure 1: Environmental Kuznets Curve (EKC). and demolition. With this background, the European Commission sets the 2030 Climate Target Plan to reduce GHG emissions to at least 55% below 1990 levels by 2030 in order to reach carbon neutrality by 2050 [15]. Accordingly, the Communication on Resource Efficiency Opportunities in the Building Sector was released to meet the need for a common European approach to reduce the environmental impact of buildings throughout their whole lifecycle [16]. This intended to establish some order among the various Green Building Rating Systems (GBRS), which are globally recognised tools to assess building sustainability through the process of identifying, measuring and evaluating alternative green solutions. Green buildings come with the most innovative technologies in the construction sector, and they comprise the advances achieved in developed countries to guarantee continuous economic growth along with environmental improvement, as expressed by the EKC curve. The first GBRS was launched in the United Kingdom in 1990 under the name of Building Research Environmental Assessment Method (BREEAM) [17]. At present, in addition to BREEAM, the most widely spread GBRSs in the EU are Leadership in Energy and Environmental Design (LEED), originally from the US [18]; Deutsche Gesellschaft fur Nachhaltiges Baden (DGNB) from Germany [19]; and Haute Qualite Environnementale (HQE) from France [20]. Other countries in the EU have been developing their own schemes with a local adaptation; however, none has reached a comparable diffusion, and international recognition and thousands of buildings are now certified under the four GBRS mentioned [21]. Green buildings have always been considered essential to lowering global GHG emissions. A study from 2008 [22] already states that energy-efficient buildings are one of the most affordable methods to mitigate climate change, but the actual effect is not quantified. Another study [23] confirms that the construction industry plays a vital role in the economic growth of a country even though it generates implications for the environment since 40% of the world's resource and energy use is linked to the construction and maintenance of buildings. The study shows that green building practices can reduce CO\({}_{2}\) emissions by up to 39%, but it does not quantify the related economic growth [23]. A more recent study [24] presents a spatial regression method to measure the impacts of GBRS on energy consumption and GHG emissions. The results imply that GBRSs guarantee a 13.2% reduction in energy consumption (with R\({}^{2}\) = 0.572) and a 3.24% abatement in GHG emissions (with R\({}^{2}\) = 0.626). However, the research ignores the economic implications and considers only Energy Star as GBRS and buildings located in an area limited to Seattle, the 18 th largest city in the US [24]. As shown in this review, the literature delineates that there is a direct link between the GDP and GHG emissions, which, in the case of a developed region such as the EU, consists of growth of the first one with a simultaneous reduction in the latter one (i.e., sustainable development). However, there is no evidence of a relationship between those two indicators and GBRS certifications.