A study published in Nature (DOI: 10.1038/s41586-023-06794-y) shows that human-caused warming has significantly reduced Northern Hemisphere snowpack over the 1981–2020 period. Using an ensemble of snowpack reconstructions, the researchers identified robust snow trends in 82 out of 169 major Northern Hemisphere river basins, with 31 of these confidently attributed to human influence. The study highlights a nonlinear temperature sensitivity of snowpack, where snow becomes more sensitive to warming as climatological winter temperatures exceed -8°C. This nonlinearity explains why widespread snow loss has not been observed yet and suggests sharper declines and water security risks in the most populous basins. The study addresses inconsistencies in snowpack responses to warming, which are attributed to observational uncertainties in snow mass, variability across timescales, and the complex relationship between forcing and snowpack. By combining observations with climate models, the researchers attribute snowpack changes to anthropogenic warming at the hemispheric and river-basin scales. They find that human emissions have contributed to the observed pattern of March snowpack trends in in situ observations and in the average of the gridded ensemble, as well as in the TerraClimate reanalysis and the Japanese 55-year Reanalysis. The study also shows that human-forced changes to temperature and precipitation have altered spring snowpack trends in 31 major river basins across the Northern Hemisphere. The spatial pattern of forced SWE trends is similar to historical trends, with anthropogenic climate change reducing spring snowpacks in mid-latitude basins by 4.1 ± 3.4% per decade and enhancing them in cold, high-latitude basins draining into the Arctic Ocean by 2.5 ± 1.8% per decade. The study emphasizes the nonlinear sensitivity of snowpack to warming, which implies accelerating water security risks for highly populated snow-dependent basins. The findings suggest that despite substantial observational uncertainty in long-term snow trends, there is a shared spatial pattern consistent with anthropogenic forcing. The study underscores the importance of understanding the impacts of climate change on snow water resources to inform water resource management decisions in the face of a less snowy future. The results highlight the need for adaptive planning and risk mitigation, particularly in regions where snowmelt plays a critical role in water supply. The study also emphasizes the value of leveraging multiple sources of uncertainty to produce reliable estimates of the effects of anthropogenic climate change on spring snowpack.A study published in Nature (DOI: 10.1038/s41586-023-06794-y) shows that human-caused warming has significantly reduced Northern Hemisphere snowpack over the 1981–2020 period. Using an ensemble of snowpack reconstructions, the researchers identified robust snow trends in 82 out of 169 major Northern Hemisphere river basins, with 31 of these confidently attributed to human influence. The study highlights a nonlinear temperature sensitivity of snowpack, where snow becomes more sensitive to warming as climatological winter temperatures exceed -8°C. This nonlinearity explains why widespread snow loss has not been observed yet and suggests sharper declines and water security risks in the most populous basins. The study addresses inconsistencies in snowpack responses to warming, which are attributed to observational uncertainties in snow mass, variability across timescales, and the complex relationship between forcing and snowpack. By combining observations with climate models, the researchers attribute snowpack changes to anthropogenic warming at the hemispheric and river-basin scales. They find that human emissions have contributed to the observed pattern of March snowpack trends in in situ observations and in the average of the gridded ensemble, as well as in the TerraClimate reanalysis and the Japanese 55-year Reanalysis. The study also shows that human-forced changes to temperature and precipitation have altered spring snowpack trends in 31 major river basins across the Northern Hemisphere. The spatial pattern of forced SWE trends is similar to historical trends, with anthropogenic climate change reducing spring snowpacks in mid-latitude basins by 4.1 ± 3.4% per decade and enhancing them in cold, high-latitude basins draining into the Arctic Ocean by 2.5 ± 1.8% per decade. The study emphasizes the nonlinear sensitivity of snowpack to warming, which implies accelerating water security risks for highly populated snow-dependent basins. The findings suggest that despite substantial observational uncertainty in long-term snow trends, there is a shared spatial pattern consistent with anthropogenic forcing. The study underscores the importance of understanding the impacts of climate change on snow water resources to inform water resource management decisions in the face of a less snowy future. The results highlight the need for adaptive planning and risk mitigation, particularly in regions where snowmelt plays a critical role in water supply. The study also emphasizes the value of leveraging multiple sources of uncertainty to produce reliable estimates of the effects of anthropogenic climate change on spring snowpack.