Today, 3.2 billion people live in agricultural areas with high or very high water shortages or scarcity, of whom 1.2 billion people live in areas with very high water constraints. From the 1.2 billion people, nearly half live in Southern Asia, and about 460 million live in Eastern and South-eastern Asia. Without immediate action, many more will be affected.
Population growth and socio-economic development are driving water scarcity as they lead rising demand for this precious natural resource. The anticipated impacts of climate change, such as uncertain rainfall and water availability, further exacerbate these factors. Consequently, the annual amount of available freshwater resources per person has declined by more than 20 percent in the past two decades.
This is a particularly serious issue in Northern Africa and Western Asia, where per capita freshwater has declined by more than 30 percent and where the average annual volume of water per person barely reaches 1 000 m3, which is conventionally considered the threshold for severe water scarcity.
Rising incomes and urbanization are leading to increased water demand from industry, energy and services, and to dietary changes implying more demand for water-intensive foods (e.g. meat and dairy products).
Healthy diets that include sustainability considerations at the food systems level can reduce the associated water consumption.
Rising competition for scarce water is driving tensions and conflicts among stakeholders, thereby exacerbating inequalities in access to water, especially for vulnerable populations, including the rural poor, women and indigenous populations.
With ten years to go until 2030, the first estimates for Sustainable Development Goal (SDG) Indicator 6.4.2 on water stress, together with persistent water shortages in rainfed agriculture, suggest that ensuring sustainable management of water for all remains a challenge.
As water is closely linked to several other SDGs, not least that of achieving Zero Hunger, managing scarce water resources well will be a critical determinant for fully achieving them.
Success is still achievable, but only by ensuring more productive and sustainable use of freshwater and rainwater in agriculture, the world’s largest water user, accounting for more than 70 percent of global withdrawals.
Many measures exist that can make water use more sustainable in different contexts around the world.
The type of measures needed will depend on the extent of the water constraints in a watershed. Water accounting and auditing, which are rarely done, should be the basis for any effective strategy for addressing water shortages and scarcity, especially in agriculture. Together, accounting and auditing can provide the basis for more realistic, sustainable, effective and equitable water management. FAO’s recent sourcebook provides a good starting point for all those wishing to implement water accounting and auditing.
Producers – many of them small-scale farmers – working on 128 million hectares (or 11 percent) of rainfed cropland affected by recurring drought can greatly benefit from water water-harvesting and water conservation techniques. By one estimate, these practices could boost rainfed kilocalorie production by up to 24 percent and, if combined with irrigation expansion, by more than 40 percent.
For herders working on 656 million hectares (or 14 percent) of drought-affected pastureland, a variety of farming measures can buffer the impact of drought and improve water productivity. Many of these measures are indirectly related to water, including disease control and animal health, livestock feeding and drinking management, mobility and stratification of production to reduce grazing pressure in arid areas.
For the 171 million hectares (or 62 percent) of the world’s irrigated cropland under high or very high water stress, priority should be given to incentivizing practices that increase water productivity – including rehabilitation and modernization of existing irrigation infrastructure and adoption of innovative technologies. These should be combined with improved water governance to guarantee equitable allocation and access to water, as well as environmental flows necessary to sustain water-related ecosystems. In sub-Saharan Africa, irrigated areas are expected to more than double by 2050, benefiting millions of small-scale farmers.
Investing in non-consumptive uses of water – for instance in aquaculture – and in non-conventional sources of water, such as water reuse and desalination, is an increasingly important strategy to offset scarcity; however innovations must be economically efficient, socially acceptable, environmentally sustainable and appropriate to the context.
Improving sustainability of water use in agriculture will also mean guaranteeing environmental flow requirements to sustain ecosystem functions, which are often overlooked.
It has been estimated that 41 percent of current global irrigation water use occurs at the expense of environmental flow requirements.
It is necessary to reduce water withdrawals and improve water-use efficiency in watersheds where environmental flow requirements are not guaranteed. This must be based on transparent water accounting and auditing.
The above solutions need to be adopted more widely to ensure sustainable water use. Policies and regulations play a central role in boosting the implementation of technologies and innovations, for example, through financing, capacity-development programmes and enforcing environmental flow requirements.
But they require appropriate allocation of water rights and secure water tenure to enable secure, equitable and sustainable access to water, especially for the most vulnerable, while ensuring environmental flow requirements.
Policy coherence and governance mechanisms across sectors are essential for efficient, sustainable and equitable water resources management. In agriculture, specifically, coherent and inclusive strategies are needed across rainfed and irrigated cropland, livestock production systems, inland fisheries, aquaculture and forestry.
There is no “one-size-fits-all” approach to addressing water shortages and scarcity. Different countries – and even different regions within countries – have different characteristics and face different challenges.
The full State of Food and Agriculture 2020 offers appropriate options for addressing water-related challenges in order to improve food security and nutrition and ensure environmental sustainability, in the spirit of the 2030 Agenda.