There has been an unwillingness to compromise or admit a particular rating system may not be the possible best tool, which has been a barrier to developing a global rating system (table 1). The unwillingness to compromise or admit a rating system may be deficient in certain areas may be a lack of knowledge and understanding on the part of those valuing or marketing buildings. A starting point is to reflect on the current development status of rating tools internationally as shown in figure 2. It is observed that most countries with existing or emerging rating tools have developed economies and often a property market where information is available. The diverse range of countries and associated climates is noted.The next step is to identify countries which have expressed interest according to World Green Building Council (WGBC) data (figure3), where it is observed these countries include the Middle East, Africa and Asia which are located relatively close to the equator.
Figure 3. Countries with Various Rating Tool Development Levels