Using real-time satellite data to track water productivity in agriculture
Measuring how efficiently water is used in agriculture, particularly in water-scarce countries, is going high-tech with the help of a new tool developed by FAO.
The WaPOR open-access database has gone live, tapping satellite data to help farmers achieve more reliable agricultural yields and allowing for the optimization of irrigation systems.WaPOR was presented during a high-level partners meeting for the Global Framework on Water Scarcity at FAO HQ in Rome. It allows for fine-grained analysis of water utilised through farming systems, generating empirical evidence about how it can be most productively used.
The continental level database is online as of today, while country level data will be made available in June for Benin, Burundi, Egypt, Ethiopia, Ghana, Jordan, Kenya, Lebanon, Mali, Morocco, Mozambique, Rwanda, South Sudan, Syria, Tunisia, Uganda, West Bank and Gaza Strip, and Yemen. Even more detailed data will come online in October, starting with pilot areas in Lebanon, Ethiopia and Mali.
WaPOR was presented this week during a high-level partners meeting for FAO's Coping with water scarcity in agriculture: a global framework for action in a changing climate. It allows for fine-grained analysis of water utilised through farming systems, generating empirical evidence about how it can be most productively used.
Worldwide water utilization - the majority of which is used by agriculture - has outpaced the rate of population growth for most of the last century and some regions are close to breaching viable limits.
"Water use continues to surge at the same time that climate change - with increasing droughts and extreme weather - is altering and reducing water availability for agriculture," says Maria Helena Semedo, FAO's Deputy Director-General, Climate Change and Natural Resources. "That puts a premium on making every drop count, underscoring the importance of meeting growing food production needs from efficiency gains."
WaPOR sifts through satellite data and uses Google Earth computing power to produce maps that show how much biomass and yield is produced per cubic meter of water consumed. The maps can be rendered at resolutions of as little as 30 to 250 meters, and updated every one to ten days.
How it works
WaPOR measures evapotranspiration, a key phase in the natural water cycle consisting of water that directly evaporates into the atmosphere and water that returns to the atmosphere after moving through a plant and emerging as vapor exuded by foliage. Evapotranspiration thus provides a direct measure of the water consumed by a crop during a growing season and, when related to the biomass and harvestable crop yield, allows for calculating the crop water productivity.
The tool can produce detailed assessments to monitor the functioning of a selected set of irrigation schemes, supporting modernization plans as well as helping assure that improvements do in fact result in all water users receiving more reliable and cost-effective water services that are more adapted to increased climate variability.
Water accounting is increasingly promoted as an indispensable tool, particularly in water-strained areas. This include coherent assessments of water resources availability, which must incorporate climate factors and require consideration of equitable entitlement - in particular allocation of water for domestic and industrial uses and for broader ecosystem services.
FAO offers technical advice on setting up appropriate water accounting and auditing frameworks.
It is estimated that for each 1 °C of global warming, 7 percent of the global population will experience a decrease of 20 percent or more in renewable water resources. Improved management of water resources are mentioned as a critical area for intervention in the vast majority of the national climate-change adaptation and mitigation plans submitted to fulfill commitments under the Paris Climate Agreement