The lack of global floorspace data presents challenges in achieving building carbon neutrality. We analyze 2,140 peer-reviewed papers on global building floorspace, focusing on energy and emissions. The top five countries publishing the most include China, the UK, the US, Italy, and Spain. The key research topics include energy modeling, emissions analysis, building retrofits, and life cycle assessments, particularly for residential buildings. Measurement approaches (top-down, bottom-up, and hybrid), each face challenges, with top-down methods offering broad estimates but tending to low accuracy, whereas bottom-up approaches are precise but requiring intensive data. Our latest simulations reveal significant floorspace growth in emerging economies, particularly India, Indonesia, and Africa. By 2070, India's per capita residential floorspace is projected to triple, whereas Indonesia's non-residential floorspace could increase sevenfold. We emphasize the need for a high-resolution global floorspace imagery database to compare energy efficiency, track decarbonization progress, and assess renovation impacts, while promoting building sufficiency and accelerating the transition to net-zero building systems.