Freshwater plays a pivotal role in global food production, with over 70 per cent of available freshwater supplies used in agriculture for pumped irrigation and rainwater harvesting. While the water cycle ensures freshwater regeneration through a continuous movement of water between the surface and atmosphere, our current usage of freshwater significantly exceeds the planet’s ability to restore its water supplies.
Climate change further complicates this balance by making precipitation patterns more unpredictable, leading to extreme droughts and intense rainfall. As global temperatures rise, evaporation rates increase, further reducing available water resources and exacerbating agricultural water stress.
In light of these challenges, efficient water management practices are essential in ensuring global food security. Without proactive conservation efforts, freshwater shortages could lead to declining crop yields, increased food prices, and greater food insecurity worldwide.
Water scarcity also threatens rural livelihoods, as many farmers depend on reliable water access for their agricultural production. Recognizing these challenges, researchers and policymakers are working to develop solutions that promote more efficient use of freshwater resources in agriculture.
In a recent paper, Xinchun Cao, a former visiting professor in McGill’s Department of Bioresource Engineering, and his colleagues constructed a water conservation model that optimizes water use through the Water-Energy-Food-Ecosystem (WEF) Nexus. This approach examines the interconnectedness of water use, energy consumption, and food production while exploring how improved water management can reduce carbon emissions.
“The purpose [of the model] is to understand the key drivers of crop water footprints and provide insights into strategies for improving water resource management in agriculture,” Cao said in an interview with The Tribune.
The WEF nexus highlights a key issue: Irrigated crop water requires energy to be extracted, transported, and distributed, emitting carbon at every stage. By reducing crop water consumption, we can simultaneously lower energy use and decrease carbon emissions, making agriculture more sustainable.
To achieve this, Cao and his team calculated the total amount of freshwater used across seven regions in China and analyzed its relationship with seasonal variations, total area of the irrigated land, fertilizer consumption, and economic conditions. They then used this data as input for the Non-dominated Sorting Genetic Algorithm-II (NSGA-II)—an optimization algorithm within the computing platform MATLAB—to minimize crop water footprints and carbon emissions while maximizing economic benefits, such as higher crop yield and reduced production costs.
By properly identifying how different factors and conditions influence crop water consumption, the researchers gained valuable insights into how current water supplies can be used more efficiently.
“While [the model] is based on data from mainland China, its methodology can be applied to other regions as well,” Cao noted. “By adapting the data inputs, the model can be used to assess crop water footprints and water conservation strategies in different geographical contexts.”
The model revealed that using fertilizer reduces crop water efficiency as it not only increases carbon emissions but also contributes to water pollution, rendering polluted water unusable and requiring more irrigation.
While the water conservation model is currently focused on agriculture, its potential extends to broader applications in policymaking and regional water management planning. Authorities could use this tool to better understand the factors driving crop water use and develop targeted strategies for conservation.
Freshwater use in Canadian agriculture increased by over 45 per cent from 2005 to 2021, a concerning figure given that Canada holds more than 20 per cent of the world’s available freshwater. Implementing more efficient water management practices could help ensure sustainable use of this critical resource.
“This research could be used to refine water conservation models, develop region-specific strategies for improving water use efficiency, and guide sustainable agricultural practices,” Cao said. “It could also contribute to broader efforts in addressing global water scarcity issues by providing a better understanding of the relationship between agricultural practices and water resources.”
