Daytime urban heat stress in North America reduced by irrigation

There is considerable uncertainty regarding the impact of irrigation on heat stress, partly stemming from the choice of heat stress index. Moreover, existing simulations are at scales that cannot appropriately resolve population centres or clouds and thus the potential for human impacts. Using multi...

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Bibliographic Details
Published in:Nature geoscience 2025-01, Vol.18 (1), p.57-64
Main Authors: Chakraborty, TC, Qian, Yun, Li, Jianfeng, Leung, L. Ruby, Sarangi, Chandan
Format: Article
Language:English
Subjects:
704/106/694/1108
704/106/694/2739
704/106/694/674
704/172/4081
Climate
Climate and human activity
Climate change
Clusters
Convection
Daytime
Earth and Environmental Science
Earth Sciences
Earth System Sciences
Geochemistry
Geology
Geophysics/Geodesy
Heat
Heat stress
Heat tolerance
Human influences
Irrigated farming
Irrigation
Regional climates
Simulation
Temperature effects
Urbanization
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Summary:There is considerable uncertainty regarding the impact of irrigation on heat stress, partly stemming from the choice of heat stress index. Moreover, existing simulations are at scales that cannot appropriately resolve population centres or clouds and thus the potential for human impacts. Using multi-year convection-permitting and urban-resolving regional climate simulations, we demonstrate that irrigation alleviates summertime heat stress across more than 1,600 urban clusters in North America. This holds true for most physiologically relevant heat stress indices. The impact of irrigation varies by climate zone, with more notable irrigation signals seen for arid urban clusters that are situated near heavily irrigated fields. Through a component attribution framework, we show that irrigation-induced changes in wet-bulb temperature, often used as a moist heat stress proxy in the geosciences, exhibit an opposite sign to the corresponding changes in wet bulb globe temperature—a more complete index for assessing both indoor and outdoor heat risk—across climate zones. In contrast, the local changes in both wet-bulb and wet bulb globe temperature due to urbanization have the same sign. Our results demonstrate a complex relationship between irrigation and heat stress, highlighting the importance of using appropriate heat stress indices when assessing the potential for population-scale human impacts. Convection-permitting regional climate simulations suggest that irrigation reduces daytime urban heat stress in North America.
ISSN:1752-0894
1752-0908
DOI:10.1038/s41561-024-01613-z