Uncertainty of 21st Century western U.S. snowfall loss derived from regional climate model large ensemble
Abstract The western United States is dependent on winter snowfall over its major mountain ranges, which gradually melts each year, serving as a natural reservoir for water resources. In a future warmer climate, much of this snowfall could be replaced by rain, making it more challenging to capture a...
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Nature Portfolio
2025-04-01
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| Series: | npj Climate and Atmospheric Science |
| Online Access: | https://doi.org/10.1038/s41612-025-01002-2 |
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| author | Jesse Norris Stefan Rahimi Lei Huang Benjamin Bass Chad W. Thackeray Alex Hall |
| author_facet | Jesse Norris Stefan Rahimi Lei Huang Benjamin Bass Chad W. Thackeray Alex Hall |
| author_sort | Jesse Norris |
| collection | DOAJ |
| description | Abstract The western United States is dependent on winter snowfall over its major mountain ranges, which gradually melts each year, serving as a natural reservoir for water resources. In a future warmer climate, much of this snowfall could be replaced by rain, making it more challenging to capture and store water. In this study, we utilize an ensemble of dynamically downscaled simulations forced by 14 global climate models (GCMs). These GCMs project wildly different futures, in terms of both temperature and precipitation change, producing significant uncertainty in snowfall projections. Here we exploit the robust statistics of the downscaled ensemble, and diagnose the sensitivity of end-of-century snowfall loss across the region to both warming and regional wetting/drying in the driving GCM. The windward slopes of the Sierra Nevada and Cascades are particularly sensitive to warming (losing ~ 15% annual snowfall per degree warming), with little influence of precipitation. By contrast, snowfall loss in the inter-mountain west is less sensitive to warming (~ 5% K−1), but is significantly offset/exacerbated by precipitation changes (~ 0.5% snow per 1% precipitation). Combining such sensitivities with the warming and regional precipitation signals in the full CMIP6 ensemble, we can fully quantify likely snowfall loss and its uncertainty at any location, for any emissions scenario. We find that the western U.S. as a whole will lose 34 ± 8% of its total volumetric snowfall by end-of-century under the high-emissions SSP3-7.0 scenario, but 25 ± 6% and 17 ± 6% under the lower-emissions SSP2-4.5 and SSP1-2.6 scenarios. |
| format | Article |
| id | doaj-art-69f4ca7d51fa4e6ba177165b3ce5c402 |
| institution | OA Journals |
| issn | 2397-3722 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Nature Portfolio |
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| series | npj Climate and Atmospheric Science |
| spelling | doaj-art-69f4ca7d51fa4e6ba177165b3ce5c4022025-08-20T02:37:58ZengNature Portfolionpj Climate and Atmospheric Science2397-37222025-04-018111210.1038/s41612-025-01002-2Uncertainty of 21st Century western U.S. snowfall loss derived from regional climate model large ensembleJesse Norris0Stefan Rahimi1Lei Huang2Benjamin Bass3Chad W. Thackeray4Alex Hall5Atmospheric and Oceanic Sciences, University of CaliforniaAtmospheric and Oceanic Sciences, University of CaliforniaAtmospheric and Oceanic Sciences, University of CaliforniaAtmospheric and Oceanic Sciences, University of CaliforniaAtmospheric and Oceanic Sciences, University of CaliforniaAtmospheric and Oceanic Sciences, University of CaliforniaAbstract The western United States is dependent on winter snowfall over its major mountain ranges, which gradually melts each year, serving as a natural reservoir for water resources. In a future warmer climate, much of this snowfall could be replaced by rain, making it more challenging to capture and store water. In this study, we utilize an ensemble of dynamically downscaled simulations forced by 14 global climate models (GCMs). These GCMs project wildly different futures, in terms of both temperature and precipitation change, producing significant uncertainty in snowfall projections. Here we exploit the robust statistics of the downscaled ensemble, and diagnose the sensitivity of end-of-century snowfall loss across the region to both warming and regional wetting/drying in the driving GCM. The windward slopes of the Sierra Nevada and Cascades are particularly sensitive to warming (losing ~ 15% annual snowfall per degree warming), with little influence of precipitation. By contrast, snowfall loss in the inter-mountain west is less sensitive to warming (~ 5% K−1), but is significantly offset/exacerbated by precipitation changes (~ 0.5% snow per 1% precipitation). Combining such sensitivities with the warming and regional precipitation signals in the full CMIP6 ensemble, we can fully quantify likely snowfall loss and its uncertainty at any location, for any emissions scenario. We find that the western U.S. as a whole will lose 34 ± 8% of its total volumetric snowfall by end-of-century under the high-emissions SSP3-7.0 scenario, but 25 ± 6% and 17 ± 6% under the lower-emissions SSP2-4.5 and SSP1-2.6 scenarios.https://doi.org/10.1038/s41612-025-01002-2 |
| spellingShingle | Jesse Norris Stefan Rahimi Lei Huang Benjamin Bass Chad W. Thackeray Alex Hall Uncertainty of 21st Century western U.S. snowfall loss derived from regional climate model large ensemble npj Climate and Atmospheric Science |
| title | Uncertainty of 21st Century western U.S. snowfall loss derived from regional climate model large ensemble |
| title_full | Uncertainty of 21st Century western U.S. snowfall loss derived from regional climate model large ensemble |
| title_fullStr | Uncertainty of 21st Century western U.S. snowfall loss derived from regional climate model large ensemble |
| title_full_unstemmed | Uncertainty of 21st Century western U.S. snowfall loss derived from regional climate model large ensemble |
| title_short | Uncertainty of 21st Century western U.S. snowfall loss derived from regional climate model large ensemble |
| title_sort | uncertainty of 21st century western u s snowfall loss derived from regional climate model large ensemble |
| url | https://doi.org/10.1038/s41612-025-01002-2 |
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