Global food supply at risk from agricultural misuse of non-renewable water – global study

The rising use of unsustainable water supplies by international food producers is putting global food and water supplies at risk and could cause basic food prices to skyrocket, a new global study led by University College London suggests.

The analysis found that the use of non-renewable groundwater for irrigation increased by a quarter from 2000 to 2010, doubling in China alone. The research suggests that unless action is taken by both producers and consumers, this trend could eventually lead to depleted water reserves, limited access to imported food and increased food prices.

Groundwater – water abstracted from underground, as opposed to water found on the surface in rivers or lakes – supplies global agriculture with 43% of the water used for irrigating crops. Some sources of groundwater are considered non-renewable, as their rate of recharge is slower than the rate at which they are used.

The depletion of local water reserves also risks putting large populations at serious danger during emergencies such as droughts, earthquakes or fires, when immediate access to water is required.

Using trade data from the United Nations and estimates of non-renewable groundwater abstraction, researchers traced the sources of water used to produce agricultural crops, including wheat, cotton and rice. The crops that contribute the most to trade of non-renewable groundwater are rice (29%), wheat (12%), cotton (11%), maize (4%) and soybeans (3%).

The country exporting the most crops produced using non-renewable groundwater is Pakistan, with 29% of global non-renewable sources embedded in trade – closely followed by the United States (27%) and India (12%).

Lead author Dr Carole Dalin, Natural Environment Research Council Research Fellow and Senior Research Fellow at University College London’s Institute for Sustainable Resources, said:

“People are rightfully food shopping with the environment in mind more than ever before – but it is not just about meat versus vegetables, organic or Fairtrade. Where and how the products are grown is crucial, and basic foods like rice and bread could have a damaging impact on global water supplies. Our research shows that unless both consumers and producers agree to adopt strategies that maximise the long-term sustainability of water use, most of the world’s population risks seeing increased food prices or disrupted food supply. Under future climate change, droughts may be more frequent in many regions and we may want to keep groundwater reserves for these periods.

Michael Puma, co-author and researcher at NASA's Goddard Institute for Space Studies and Columbia University, said:

Say I'm in Japan, and I'm importing corn from the United States. It's important from Japan's perspective to know whether that corn is being produced with a sustainable source of water, because you can imagine in the long term if groundwater declines too much, the United States will have difficulty producing that crop.

Thomas Kastner, Senior Scientist at the Senckenberg Biodiversity and Climate Research Centre, Germany and the Alpen-Adria-University, Austria, said:

Our work shows where trade flows are contributing to the unsustainable, and ultimately potentially dangerous, use of water resources.  “The use of non-renewable water in one place can put food supply in distant regions at risk. This study can help us identify entry points for a more sustainable global water resources management.

Yoshihide Wada, Senior Research Scholar and Deputy Director of the International Institute for Applied Systems Analysis (IIASA)’s Water Program, said:

The products that consumers buy at a supermarket may have very different environmental impacts depending on where they are produced and how they are irrigated.  “In order to help consumers make more sustainable choices about their food, producers should consider adding water labels that make these impacts clear.

Notes to editors:

1. View 'Groundwater depletion embedded in international food trade', published today in Nature.
2. The UCL Institute for Sustainable Resources generates knowledge in the globally-sustainable use of natural resources and trains the future leaders of this field. We are part of the Bartlett: UCL’s global faculty of the built environment. 
3. For media enquiries, please contact Alex Blackburn on a.blackburn@ucl.ac.uk or 0203 108 9860