The map's two load-bearing columns
Comparing building climatization needs globally requires one common language for structures. The study combines building footprints and Earth observations in equally sized geographic tiles, placing more than 9,000 urban centres inside one computational frame. Footprint and height construct the stock's geometry; construction epoch adds a time layer for structures built under different technical standards. The result is a consistent world model rather than an audit of individual buildings.[1]
The model's two load-bearing proxies are construction epoch and compactness. With 43 percent of buildings predating 1980, older stock carries substantial weight in the map. Compactness approximates the relation between exterior surface and enclosed volume, so less favourable forms receive a different vulnerability score under the same local heating or cooling need. Energy meters, HVAC efficiency and indoor temperatures are not observed directly. The map is therefore a screening model assembled from building data, not a metering network measuring energy use.[1]
The distance between a scenario output and a building audit
Under this construction, about 48 million people now fall within areas where buildings vulnerable relative to local heating or cooling needs are concentrated. That count does not directly enumerate energy poverty, failed climatization systems or measured temperatures in individual homes. It brings proxy features of building stock together with local climate needs in one model. The 48 million is therefore a comparable exposure screening result rather than a definitive building-level inventory.[1]
A simplified shape factor plus footprint and height errors form the model's geometric error budget. Renovation rates, HVAC efficiency, cultural adaptation and occupant behaviour can then make identical geometry perform differently in practice. Those limits narrow the map's proper use. It can rank regions that need deeper field work at city or national scale. Judging one home's safety, energy bill or retrofit prescription still requires local measurements and a building audit.[1]