No economic sector consumes as much freshwater as agriculture and researchers are now calling for a paradigm shift to curb this trend.
While agriculture has increased provisioning ecosystem services such as food, fiber and timber production, it has also substantially impacted the very ecosystems agriculture relies on.
In a special issue in the journal "Agricultural Water Management", centre researchers Line Gordon and Malin Falkenmark along with Max Finlayson from Charles Sturt University in Australia highlight emerging issues in the trade-off among ecosystem services that have been generated due to decreased water quality and quantity caused by agricultural production.
A tall order
Agriculture covers roughly 40 percent of the world´s terrestrial surface and has consequently become a main contributor to environmental changes. One of the major ways in which this takes place is through its interaction with water.
- Agriculture has substantially modified the global hydrological cycle in terms of both water quality and water quantity. For instance, around 66 percent of all water withdrawn for direct water use is being used for agriculture, says co-author Line Gordon.
It´s a tall order: if the world is to achieve its Millennium Development Goals of eradicating hunger, a doubling of food production over the coming 20-30 years is required. But for the agriculture sector to produce more food, more water is needed, and the world is running out of it.
Extensive water use has caused substantial changes to river flow patterns affecting several large rivers around the world as well as contributing to a doubling of nitrogen fixation and phosphorous use. The ecosystem effects of these impacts are significant: downstream fisheries face a serious decline affecting both small-scale as well as bigger, industrial fisheries; the quality of drinking water drops and reduced water quantity leads to loss of crucial wetlands and coastal ecosystems.
- Humanity is facing an enormous challenge in finding sustainable trade-offs between an increase in agricultural production that can contribute to food security and economic growth on one hand, while dealing with the losses of important ecosystems that sustain human well-being on the other, Gordon says.
Issues that need urgent attention
The challenge to produce more food globally while simultaneously negatively affecting ecosystem services is partly taken seriously at international level. The partial rehabilitation of some iconic symbols of past follies such as the Aral sea and the Mesopotamia marshes are examples of this, however there is still a hug gap between what agronomists and hydrologists think is possible and what ecologists deem necessary.
Gordon, Falkenmark and Finlayson present some policy options and management approaches that can help strike a balance between increased food production and the preservation of ecosystems.
One strategy is to improve management practices on agricultural lands to increase the efficiency with which water is used to produce food. Research has shown that future water needs could be cut by more than 50 percent with increased water productivity.
Farewell to monocroping
A second strategy is to shift from monocroping to multifunctional agro-ecosystems to create synergies among ecosystem services.
A review of investment in resource-conserving agriculture that focuses on multiple goals showed that increased yields could go hand in hand with reduced environmental impacts through increased water use efficiency, improved water quality and increased carbon sequestration.
Furthermore, biodiversity is important for securing multifunctionality by acting as an insurance mechanism by increasing ecosystem resilience.
- Species may seem redundant during some stages of ecosystem development but can be crucial for ecosystem reorganization after disturbance, Gordon says.
The third strategy is to link agricultural water management and management of downstream water systems in order to strike necessary trade-offs.
- Involving stakeholders who can negotiate unavoidable trade-offs between upstream food production and downstream ecosystem services is important in this process, Gordon says.
Source: Gordon, L., Finlayson, C.M., Falkenmark, M. 2010. Managing water in agriculture for food production and other ecosystem services. In Agricultural Water Management Volume 97, Issue 4, April 2010, Pages 512-519. http://dx.doi.org/10.1016/j.agwat.2009.03.017
See seminar with Line Gordon on water management, development and food security: