Agriculture
Its abstraction has played a major role in accelerating food production from the 1970s onwards, especially in semi-arid and arid areas with limited precipitation and surface water.
Currently 70% of global groundwater withdrawals, and even more in arid and semi-arid regions, are used in the agricultural production of food, fibres, livestock and industrial crops, and an estimated 38% of the lands equipped for irrigation is serviced by this resource.
In order to meet global water and agricultural demands by 2050, including an estimated 50% increase in food, the development of groundwater could act as a catalyst for improving agricultural productivity and economic growth by increasing the extent of irrigated areas.
Challenges
Groundwater depletion due to intensive withdrawals for agriculture is becoming an issue of increasing concern in certain areas, where it threatens to undermine food security, basic water supply, climate resilience, and the environmental integrity of groundwater-dependent wetlands and watercourses.
Unsustainably high abstraction rates are concentrated in arid and semi-arid areas, where population growth and expansion of irrigated areas have led to rapid growth in water demand. While in other regions, such as Sub-Saharan Africa, the large volumes of renewable groundwater remain largely underexploited.
Agriculture is the primary cause of groundwater pollution in rural areas, and worldwide it is estimated that agricultural pollution has overtaken contamination from settlements and industries.
Nitrate, from chemical and organic fertilizers, is the most prevalent anthropogenic contaminant in groundwater globally, leading to the eutrophication of surface waters. Insecticides, herbicides and fungicides, when improperly applied or disposed of, can also pollute groundwater with carcinogens and other toxic substances.
Causes of groundwater pollution
The opportunities offered by the vast shallow aquifers remain largely underexploited.
Use of groundwater for irrigation
Economic instruments for pollution control of surface and groundwater are increasingly employed, but evidence suggests that laws and regulations to prevent groundwater pollution from agriculture are generally weak. Policies to promote information and awareness to change farmer behaviour and incentivize for the adoption of Best Management Practices in agriculture can help prevent pollution at the source.