Researchers at Utrecht University found that heatwaves have a more pronounced impact on water use across industries than droughts. By analyzing data from the past 30 years, they found significant differences in water use patterns in response to extreme weather events across industries and regions. These findings highlight the need for more detailed water use data, especially from understudied regions, to enhance global water management strategies under climate change.
The growing global population and the increasing frequency of extreme weather events put our water resources at risk. However, understanding of how different sectors use water during drought-heatwave events is limited, especially at large scales.
To fill this gap, a team of scientists from the Department of Physical Geography at Utrecht University studied how water use across sectors is affected by droughts, heatwaves and compound (merging) events around the world. Their findings, published in Environmental Research Letters, show that heatwaves have a greater impact on sector water use than the impact during droughts.
The study is the first global study to quantify sectoral water use responses to extreme droughts, heatwaves and compound events. Sectoral water use responses are understood as how the water use patterns of various sectors (i.e. domestic, irrigation, thermoelectric energy, manufacturing and livestock) are affected by droughts, heat waves and compound events, which may cause them to increase or decrease water use, or to show no particular response to these extreme hydroclimatic phenomena.
The researchers analyzed extensive data on water use across sectors at global, national and local scales over the past 30 years. "We focused on water use in different sectors, namely irrigation, livestock, household, energy and manufacturing, because we expected these sectors to have specific responses to the occurrence of different extreme events," said Gabriel Cardenas-Bellesa, a PhD student at Utrecht University and first author of the publication.
The analysis shows that extreme events over the past 30 years have had a significant impact on water use patterns, but these impacts vary widely across industries and regions around the world. "Socioeconomic factors and public water management plans have a large impact on water use responses, and the impact is even greater during extreme events. For example, the western continental United States reduces water use during extreme events, while the central United States increases water use," Cardenas said. Additionally, the findings show that, in general, domestic and irrigation water use has the highest priority globally, but during extreme weather periods, more stringent measures are in place for domestic water use. "
The analysis also showed that heatwaves and drought-heatwave compound events overall had a greater impact on water use than droughts alone. "Heat waves and compound events result in higher water use due to temporary increases in water demand at higher temperatures compared to longer duration events such as droughts, but due to the shorter duration of such extreme events, water demand can still be met," Cardenas said.
The findings indicate an urgent need to collect more water use data to better understand the impact of extreme events and climate change on different water use sectors and to improve assessments of future water scarcity. "Our study is a first step towards assessing multi-sector water use behavior during extreme events. However, to better understand water use behavior across sectors and improve water management strategies, more local-scale information is needed from data-scarce regions such as Africa, Asia and parts of South America."