The role of Earth Observation in advancing our understanding of high sustained temperature leading to dry conditions compound events: the UK Science Case

Between January and June 2022, the UK experienced the driest weather in over 40 years. This culminated in July, when temperatures exceeded 40 degrees Celsius for the first time since records began. Unprecedented hot, dry conditions resulted in hazards and multi-hazard interactions that have not previously been experienced in the UK. This expression of high temperature induced multi-hazards along with more commonly seen hot weather induced hazards with longer residence times may lead to increased direct and indirect impacts on society and ecosystems as experienced in other parts of the world. The accurate, timely, and efficient derivation of information and data products from EO data and technologies is instrumental in predicting, monitoring, assessing, and evaluating the occurrence of single natural hazard events and their potential impacts. What is not so well understood is the role of EO-derived environmental indicators in characterizing complex causal relationships and underlying mechanisms leading to cascading or compounding multi-hazard impacts. This may be demonstrated using time series analysis of a single indicator or derived from several time series of two or more indicators of interrelated hazard events such as droughts, heatwaves, subsidence, wildfires, flooding, and landslides. In this study, we aim to advance the state-of-the-art by using long-term EO satellite data to identify thresholds, trends, and tipping points within time series of established environmental metrics which indicate the dynamic evolution of a multi-hazard event. This information will be complemented by in-situ observations and local, regional, and global models to identify environmental precursors and chains of effects that may be suggestive of multi-hazard event onset conditions. By utilizing several vulnerability and impact assessment models, such as impact chains, we will demonstrate the utility of EO techniques and datasets in enhancing multi-hazard risk assessment and management. In this presentation, we briefly introduce the research context, questions, methodological approaches, preliminary results, and future direction of the UK Science Case as part of the High Impact Multi-hazards Science (EO4Multihazards) project funded by the European Space Agency (2023 2026).