A Look at the Links Between Water, Food Security, and Ecosystems

22 March 2012 | Nine billion people are expected on Earth by 2050. That’s an extra two billion mouths to feed, or the equivalent of another Africa, North America, and Europe appearing on the planet. Pressure will intensify on agricultural lands and in turn on water resources, since water is a major constraint on the amount of food that a society can produce. What’s more, individual water footprints  are likely to grow: a recent report from the UN Environment Programme (UNEP) and the International Water Management Institute (IMWI) notes that if current trends of urbanization and changing dietary habits continue, water required for agriculture will increase between 70 and 90 percent by 2050.

Yet 40 percent of the world’s population could be facing severe water scarcity by mid-century, according to just-released estimates from the Organization for Economic Co-operation and Development (OECD). Taken together, these numbers are troubling: on one side of the equation, more people each consuming more water; on the other, predictions of increasing drought, changing rainfall patterns, falling water tables, and shrinking rivers and lakes.

Climate change  and ecosystem degradation will only exacerbate scarcity of clean water. Around the world, aquifers are being overdrawn, soil nutrients depleted, and water resources polluted with eroded soils, little-treated waste, and agricultural fertilizers. These actions do not only limit agricultural productivity in the long run, they damage other functions of healthy ecosystems that societies depend on.

Forests, grasslands, and wetlands, for example, can filter out water pollution, regulate stream flows, recharge aquifers, limit erosion, and absorb and store flooding. These benefits are collectively known as “watershed services,” and society can’t do without them. A  healthy environment can also support soil nutrient cycling, the insects and birds that pollinate our crops, and the biodiverse ecosystems that offers resilience against agricultural pests and disease, a changing climate, and other system shocks.

Around the world, ecosystem services like these are in crisis. We will experience as much as a 25 percent gap  between food supply and demand by mid-century from ecosystem service degradation (biodiversity, soil nutrient loss and soil erosion, declining storage capacity, vulnerability to pests and disease due to monoculture). UNEP/IMWI estimate  that we’re losing five to ten million hectares of agriculture land every year to degradation.

What’s more, these problems aren’t evenly distributed. Developing countries are both disproportionately vulnerable to climate change and disproportionately dependent on agriculture. And global water scarcity particularly threatens women, who are often responsible for collection and food production, and at greater risk for malnutrition when food is scarce.  But this means also that better management of water-food-ecosystem linkages holds tremendous potential for poverty alleviation and benefits for women.

As UNEP/IMWI argue in Ecosystems for Water and Food Security, these challenges require a global shift to managing agroecosystems, not agriculture. An ecosystems approach to water and food security  means “growing” both food and ecosystem services like pollination, adequate infiltration to the water table, or soil nutrient cycling.

It also means investing in our natural water infrastructure that can deliver clean, ample water supplies cost-effectively and sustainably.

And, as FAO notes, the agricultural sector can grow more food with less water, through more efficient irrigation and less water-intensive crops, water reuse and alternative supplies (such as treated wastewater), and rainwater harvesting.

– Stay tuned for updates: we’ll continue to cover World Water Day over the course of the day.
– Visit the official website of World Water Day to learn more about the water-food security challenge.