LAUSR

related hazards on human mortality, labour capacity, physical activity, well-being, infectious disease transmission and food security and undernutrition. The paper describes the Lancet Countdown monitoring system for health indicators, which relies mainly on global reanalysis data for detailed information about heatwaves, precipitation extremes, wildfires, droughts, warming and impacts on ecosystems. Rapid changes in the Greenland cryosphere have greatly affected the local environment and the communities that depend on it. Melting of the Greenland ice sheet has major consequences for global sea level rise. The ability to monitor and understand those changes is paramount. The study by Box et al. (2023) provides a thorough analysis of the quality of available data on the Greenland icesheet and precipitation patterns from global and regional reanalysis data. The paper by Prudhomme et al. (2024) describes the development of global hydrological reanalyses, which are generated by combining physically based hydrological models with meteorological data from atmospheric rea-nalyses. Hydrological reanalyses are used to monitor land water resources and ocean dynamics, to improve our understanding of large-scale hydrological extreme fluctuations and for the development of early warning systems. They also provide long-term context for identification of extreme hydrological events, such as droughts and floods. Reanalysis has become an indispensable resource for climate monitoring, risk assessment and local adaptation activities, as illustrated with the papers in this special issue. In recognition of the crucial role of reanalysis for climate services, the World Meteorological Organization (WMO) has established a Lead Centre for coordination of assessment of multi climate reanalysis (LC-GCR), to be led by ECMWF. The result, we expect, will be further improvements in reanalysis quality, access and utility to the benefits of users around the world.