Soil drought can mitigate deadly heat stress thanks to a reduction of air humidity

Wouters, Hendrik; Keune, Jessica; Petrova, Irina Y.; Heerwaarden, Chiel C. van; Teuling, Adriaan J.; Pal, Jeremy S.; Arellano, Jordi Vilà-Guerau de; Miralles, Diego G.

doi:10.1126/sciadv.abe6653

Cited by 44 publications

(40 citation statements)

References 55 publications

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“…Global warming caused the increased severity and frequency of deadly heatwaves over majority of the globe. The compound increase in atmospheric moisture and heatwaves results in a rapid rise in moist heat stress over the last four decades, which is more prominent in subtropic regions (Wouters et al., 2022). For instance, the subtropic areas are close to the 35°C survivability limit (Raymond et al., 2020).…”

Section: Discussionmentioning

confidence: 99%

Improved Water Savings and Reduction in Moist Heat Stress Caused by Efficient Irrigation

Ambika

Mishra

2022

Earth's Future

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Intensive agriculture and irrigation play a crucial role in the food security of India. However, irrigation has considerably impacted regional climate and groundwater sustainability. Notwithstanding the profound implications of irrigation on dry and moist heat and groundwater depletion, the role of efficient irrigation on moist heat stress reduction and water savings remains unexplored. Here, we use observations and simulations from the Weather Research Forecasting (WRF) model to examine the impact of efficient (drip) irrigation on moist heat stress and water savings over the Indo‐Gangetic Plain. Irrigated area has increased more than 20% over the Indo‐Gangetic Plain during the 1970–2005 period. As a result, irrigation water use has increased dramatically over the region. The irrigation expansion partly contributed to the rise of 0.46°C (P‐value < 0.05) in the summer (April–May) season wet‐bulb temperature over the Indo‐Gangetic Plain, which is a measure of moist heat stress. The Indo‐Gangetic plain exhibited a strong land‐atmospheric coupling between soil moisture and dry and moist heat. WRF simulations conducted using ERA5 as boundary conditions show that switching from the conventional (channel) to the efficient (drip) irrigation leads to a moderate warming (∼0.2°C) and a significant decrease in specific humidity over the Indo‐Gangetic Plain. The reduction in specific humidity due to efficient irrigation significantly lowers the moist heat stress (wet‐bulb temperature) and increases water savings. Our findings show the double benefits of efficient irrigation to curb the rapidly declining groundwater and increase moist heat stress in the region.

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Section: Discussionmentioning

confidence: 99%

Improved Water Savings and Reduction in Moist Heat Stress Caused by Efficient Irrigation

Ambika

Mishra

2022

Earth's Future

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“…However, the cooling caused by irrigation has amplified human exposure to moist heat stress through increased air humidity, especially in arid regions where there is a greater increase in evaporation from irrigation [124,125]. Thus, irrigated agriculture in a warmer climate may intensify lethal heat stress by exposing humans to heat and humidity too severe for human survivability [126][127][128][129]. Moist heat might also reduce labor productivity of farmers [130] and therefore affect agricultural productivity and food security.…”

Section: Hydroclimatic Feedbackmentioning

confidence: 99%

Adapting agriculture to climate change via sustainable irrigation: biophysical potentials and feedbacks

Rosa

2022

Environ. Res. Lett.

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Irrigated agriculture accounts for ∼90% of anthropogenic freshwater consumption, is deployed on 22% of cultivated land, and provides 40% of global food production. Expanding irrigation onto currently underperforming rainfed croplands is crucial to meet future global food demand without further agricultural expansion and associated encroachment of natural ecosystems. Establishing irrigation is also a potential climate adaptation solution to alleviate heat- and water-stress to crops and reduce climate variability and extremes. Despite irrigation being one of the land management practices with the largest environmental and hydroclimatic impacts, the role of irrigation to adapt agriculture to climate change and achieve global sustainability goals has just started to be quantified. This study reviews biophysical opportunities and feedbacks of ‘sustainable irrigation’. I describe the concept of sustainable irrigation expansion—where there are opportunities to increase agricultural productivity over currently water-limited rainfed croplands by adopting irrigation practices that do not deplete freshwater stocks and impair aquatic ecosystems. Expanding sustainable irrigation may avert agricultural expansion but create additional externalities that are often neglected. This review highlights major gaps in the analysis and understanding on the role of sustainable irrigation expansion to adapt agriculture to climate change. This study reviews the implications of a potential sustainable irrigation expansion on (a) global food security, (b) hydroclimatic conditions, (c) water quality, (d) soil salinization, (e) water storage infrastructure, and (f) energy use. These implications help to explain the challenges of achieving sustainability in irrigated agriculture and thus also point toward solutions and future research needs.

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“…Heat stress for humans is dependent not only on temperature, but also on wind speed and humidity (Buzan and Huber, 2020;Matthews, 2018). Through reduced evaporative cooling and increased entrainment of dry air above the atmospheric boundary layer, the lethality of heat extremes above dry soils can be reduced (Wouters et al, 2022). In this study, we find an increasing T max divergence alongside increasing EF in 20% of the warm vegetated land area (Supplementary Figure 6.A6b), which suggests potentially higher heat stress than reflected by temperature alone as terrestrial evaporation can increase humidity and related lethality.…”

Section: Discussionmentioning

confidence: 99%

“…In the concurrent season, the ELI and related reductions in evaporative cooling can be computed and trends can be computed similar to Chapter 6. Further, in addition to temperature, the focus can be shifted to more impact-relevant metrics, as for heat stress concurrent wind speed and humidity during heat extremes are also important (Buzan and Huber, 2020;Matthews, 2018), as reduced humidity during such extremes might even decrease human mortality (Wouters et al, 2022). These analyses could complement the findings presented in Chapter 6.…”

Section: Changing Heat Extreme Characteristics In Response To Increas...mentioning

confidence: 95%

“…Through modulating the surface flux partitioning and corresponding diurnal ABL evolution, the prevailing evaporative regime can impact weather and climate, particularly so during extreme events like heat waves and droughts (Guillod et al, 2015;Hirschi et al, 2011;Koster et al, 2016;Koster et al, 2004;Taylor et al, 2012), which have severe implications for human health (Bogdanovich et al, 2022;Wouters et al, 2022). The other way around, the impact of extreme events on the land surface can also be modulated by the evaporative regime at hand (Hauser et al, 2016;Hirschi et al, 2011;Miralles et al, 2014b), such that a heat wave and a corresponding drought over water-limited land surfaces might reduce ET or other proxies related to vegetation functioning, but can be beneficial for energy-limited land surfaces (Flach et al, 2018;Zscheischler et al, 2014a).…”

Section: Implications On Extreme Eventsmentioning

confidence: 99%

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Mapping terrestrial evaporation regimes : a data-driven analysis of land-atmosphere interactions under climate change

Denissen¹

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Soil drought can mitigate deadly heat stress thanks to a reduction of air humidity

Abstract: Soil drought can mitigate deadly heat stress thanks to a reduction of air humidity.

Cited by 44 publications

References 55 publications

Improved Water Savings and Reduction in Moist Heat Stress Caused by Efficient Irrigation

Improved Water Savings and Reduction in Moist Heat Stress Caused by Efficient Irrigation

Adapting agriculture to climate change via sustainable irrigation: biophysical potentials and feedbacks

Mapping terrestrial evaporation regimes : a data-driven analysis of land-atmosphere interactions under climate change

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