The OECD set of indicators is based on historical observational data and forward-looking projected data. The observed historical data has been collected and recorded and goes back as far as 1979 (Maes et al., 2022[10]). Meanwhile, the forward-looking projected data goes up until 2100, comprising anomalies for the 2030s, 2050s, 2070s and 2090s relative to the 1995-2014 climate reference period (Maes et al., 2025[11]). Historical indicators reflect what has happened, while forward-looking indicators project what will happen.
Notwithstanding, historical and forward-looking indicators are based on different underlying data sources and methodologies. These indicator datasets should therefore be interpreted with caution since these are not directly comparable. Nevertheless, the 47 years of historical data combined with 86 years of forward-looking projections offer the basis for a long-term analysis of climate change, highlighting the exposure of populations, croplands, forests, and urban areas to climate-related hazards. These indicators illustrate the trend that climate change impacts are already visible by analysing historical trends and are projected to worsen in many regions across the world, under various climate scenarios. For a complete description of the methodologies behind historical and forward-looking indicators, please see (Maes et al., 2022[10]) and (Maes et al., 2025[11]).
Information on disaster events and their related costs has limitations due to inconsistent reporting by national governments and in international databases. Loss databases are essential to assess policy and monitor progress, but they are hardly ever mandated by national or supra-national legislation. There are several supra-national framework directives, but they remain vague when it comes to recording losses from disasters; their implementation would hugely benefit from the availability of such information.
No single database offers complete coverage of losses from disaster events. This year’s report uses the Munich Re database on natural disaster losses – an extensive resource that is critical for understanding the impacts and trends associated with such events. It includes detailed data on floods, storms, earthquakes, droughts, forest fires, heat waves, cold waves, frost, hail, tsunamis and other natural catastrophes. For the purposes of this report, focus is given to natural catastrophes linked to climate change; therefore, earthquakes are excluded from the analysis.