As the total amount of freshwater on Earth is fixed and cannot be changed, food production and some of the world's largest cities face serious risks, making efficient and effective allocation of paramount importance, according to two new reports from the Food and Agriculture Organization of the United Nations (FAO).
Climate change impacts are already impacting water supply for agricultural production systems, with symptoms ranging from floods and droughts to increased rainfall variability and rising temperatures, as well as competition between users where water stress and scarcity are already significant.
The reports, presented at Stockholm World Water Week 2021, aim to give stakeholders and policy makers around the world critical data about trends in water use and availability. "Progress on change in water-use efficiency" and "Progress on level of water stress" both provide detailed updates on the global status and acceleration needs to achieve Sustainable Development Goals (SDGs) 6.4.1 and 6.4.2, for which FAO is the UN's custodian agency.
"Water is the essence of life and at the core of the agri-food systems," FAO Director-General QU Dongyu states in the foreword. "The path to water efficiency passes through sustainable agri-food systems."
"Water management is at the core of achieving the SDGs, not only SDG 6 - Water for all - but also SDG 2 - Zero Hunger," said FAO Deputy Director-General Maria Helena Semedo. "Water challenges in agriculture, such as water scarcity, pollution and wastage, must be addressed as a matter of urgency in order to transform and make food systems more resilient, particularly as we confront the alarming complications of climate change."
The FAO ‘SDG 6.4.2 Level of Water Stress' report assesses water stress throughout global regions, emphasizing the urgent need to develop resilient water management systems, particularly for irrigated and rainfed agricultural production. Increasing water use efficiency practices in all sectors, particularly the agricultural sector which accounts for an estimated 70 percent of global freshwater withdrawals, represents a win-win strategy that promotes better water demand management practices as well as adapting to climate change impacts through strengthening system resilience.
The water stress report observes that about one-third of the world's population (or 2.3 billion people) live in countries experiencing water stress, while 10 percent (733 million) live in countries with high or critical water stress, which has a significant impact on water access and availability for personal needs. Moreover, farmers may experience increasing inequalities in their access to water resources in a water stress situation, highlighting the need to promote not only sustainable but also inclusive and integrated management and governance of the different water sources.
The FAO ‘SDG 6.4.1 Change in Water Use Efficiency Over Time' report provides a valuable benchmark on water efficiency, tracking recent trends - a 9 percent efficiency increase from 2015 through 2018 - and offering the potential to inform further improvements in the years ahead. This report points to trade as among the factors with potential to influence water use efficiency, and highlights virtual water exchanges as a promising possible contributor to the effort to account for water use properly. The report emphasizes the need to seek balance between food security, sustainable water use, and economic growth.
FAO's Land and Water Division, originator of these reports, is involved in numerous other projects that directly address water scarcity and promote water use efficiency. These include AQUASTAT, a global data set, WaPoR, a remote-sensing programme to measure water productivity, Building Forward Better, an initiative bolstering human capital in fragile contexts, Field guide to improve water use efficiency in small-scale agriculture, with case studies in Africa, Water Productivity , the yield gap and nutrition, an innovative assessment of water, yields and nutritional needs in Ethiopia, the WASAG White Paper on water productivity, and thought leadership and information on the role of land and water tenure.
Some key takeaways
From 2015 through 2018, global water-use efficiency rose from $17.30 to $18.90 per cubic meter, or 9 percent, with the industrial sector leading the improvements.
For 86 countries with regularly reported water-use data, efficiency in the agricultural sector has increased 60 percent from 2006 to 2018.
Globally, some 18.4 percent of the total renewable freshwater resources were being withdrawn in 2018, although the figure was above 25 percent in Central and Southern Asia and Northern Africa.
When measured by river basins rather than national boundaries, severe water stress zones can be found in many countries including Chile, China, Mexico, South Africa and the United States of America.
Extremely low water stress values may indicate the inability of a country to properly use its water resources for the benefit of the population.
Urban, agricultural and industrial water uses are highly interdependent and linked with population growth, climate-related issues and irrigation practices. Such factors triggered a shutdown of water supply in Cape Town in 2018 and large cities such as Beijing, London, Mumbai or Tokyo are susceptible to face water crises by 2050.