Climate change both increases and decreases winter snowmelt across North America

Snowmelt, a vital source of freshwater for a large portion of North America’s population, is increasingly vulnerable to the impact of climate change. Air temperature and precipitation are significant climatic controllers regulating snowmelt dynamics. In this study, we quantified the response of winter snowmelt magnitude to changing temperature and precipitation across North America (Canada and the United States) using gridded, observation-driven data and future projections. Our analysis of far-future conditions (2091-2100) reveals a significant increase (>60%) in winter (November-March) snowmelt in northern latitudes, while southern latitudes are projected to experience a decline (<38%). Projected snowmelt changes are strongly associated with changes in winter temperature, while projected declines are consistent with regions experiencing reduced snowfall under warming climates. Our findings suggest that the probability of an increase in winter snowmelt is high under the warmer and wetter climatic conditions prevailing in northern regions. In contrast, winter snowmelt across southern latitudes is likely to decrease. Plain language summary: Snowmelt plays a critical role in sustaining water resources for large populations across North America. As temperature and precipitation are major climatic factors regulating snowmelt dynamics, changes in these variables can affect the magnitude of snowmelt. Given projected climate change, it is essential to assess the vulnerability of snowmelt magnitude to changing temperatures and precipitation to understand future water availability. Our analysis of future winter snowmelt under compound changes in air temperature and precipitation across North America indicates that winter snowmelt could increase by 60% in many regions of Canada. In contrast, in southern areas, the winter snowmelt volume could decrease by as much as 38%. These results suggest that warmer winters are the primary driver of increased snowmelt, while reduced snowfall primarily governs the projected snowmelt declines.

Subjects

Climate change

Compound impacts

Multivariate copula

North America

Winter snowmelt

DDC Class

551: Geology, Hydrology Meteorology

Lizenz

https://creativecommons.org/licenses/by/4.0/

Publication version

publishedVersion

Name

1-s2.0-S0022169426015076-main.pdf

Type

Main Article

Size

7.09 MB

Format

Adobe PDF

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Climate change both increases and decreases winter snowmelt across North America