Unfit for stranding: a panel-scale multimodal-LLM audit of building-decarbonisation disclosure (BeDA)

Buildings account for roughly 34% of global final energy use and 37% of energy-related CO2 emissions. Stranding regulation now being enacted (NYC Local Law 97, the EU EPBD recast, CSRD ESRS E1) presupposes that a building portfolio’s carbon intensity can be measured per square metre and compared against a science-based pathway. Whether corporate disclosure is actually fit for that comparison has not, to our knowledge, been measured at scale. We introduce BeDA (the Built-environment Decarbonisationdisclosure Auditor), a multimodal large-language-model instrument whose standards-compliance score is reliable across models and model families, and apply it to a global firm panel (2,246 firms, 2003–2023). Most disclosure is unfit: only about one built-environment firm-report in five discloses operational carbon intensity per m2 (21.5%, Wilson 95% CI [16.4%, 27.7%]; 45.5% in real estate). The rate is roughly twice as high in Europe as in the United States (64–74% versus 37% for listed real estate). Among the 215 real-estate firm-reports for which an intensity can be constructed, 39% already sit above the CRREM 1.5 ◦C pathway. Credibility does not predict stranding readiness once portfolio size is controlled; this is a screening tool, not a forecast. The main obstacle to enforceable building-stranding regulation is therefore a measurable, jurisdiction-specific reporting gap, one that a targeted disclosure mandate can close and that BeDA can monitor.