Turning groundwater into farmers’ underground insurance against climate change
Despite the recent drought in California, farms have continued to supply water-intensive crops such as fruits and nuts to consumers both in the US and around the world. Doing so has not always been easy for farmers – or for the environment. Agricultural producers turned to groundwater to irrigate their crops, a change made so intensively that in some parts of the state the ground started sinking because the water table had fallen so much.
The south-western United States is not an isolated case. The green fields of India’s Punjab state hide a similar problem. Groundwater supplies around 60% of India’s water needs for agriculture but the country suffers from depletion and pollution of this water resource in approximately 60% of its states. In Punjab, India’s breadbasket, demand for water already outstrips supply by 38%.
These countries are only examples of a growing global policy challenge. The disruption that climate change poses to water supplies in many parts of the world only increases the importance of correctly managing this resource. Getting groundwater policy right could ensure that farmers have supplies of water to last them through dry periods.
The OECD and the International Food Policy Research Institute (IFPRI) have organised a panel discussion on groundwater and agriculture at the Global Forum for Food and Agriculture (GFFA) 2017 on Friday 20 January in Berlin. The speakers will discuss how this vital resource for agriculture around the world can be properly managed to ensure that policy decisions taken today will protection future food production. The outcomes of the discussion will feed into the following day’s GFFA meeting of agriculture ministers where the topic of water and agriculture will be discussed.
Groundwater supplies need to be properly managed because this resource has the potential to provide a reliable, on-demand source of water to irrigate crops, and has become central to agricultural production in a range of countries. Groundwater accounts for over 40% of global irrigation on almost 40% of irrigated land and has become indispensable for agriculture production in many countries. It accounts for half of South Asia’s irrigation and supports two-thirds of grain crops produced in China. OECD countries alone extract an estimated 123.5 km3 of groundwater each year to irrigate semi-arid areas.
This heavy use of groundwater has become unsustainable in many regions. High rates of extraction may boost production today but doing so also causes problems such as land subsidence, salinisation, and other forms of land and water quality degradation.
These knock-on effects may be putting global food security at risk.
Already a number of OECD regions are facing challenges in pumping water out of the ground. A quarter of surveyed irrigating regions in the OECD that use groundwater are seeing a major reduction in well yields as well as significant increases in pumping costs (see Figure 1).
Importantly, there are efforts that policy makers can implement that can ensure that groundwater can continue to feed billions of people around the world.
“You can’t manage what you can’t measure” has become a mantra for groundwater campaigners in California. The same approach must be applied in countries around the world. Greater information needs to be collected about stocks and flows over time – data without which it becomes almost impossible to implement effective management.
And where groundwater stresses are identified, governments must put in places measures that not only reduce water demand, but also take into account how surface and groundwater interact. These measures would go some way to preventing collapses in water supply for agriculture. Excess groundwater demand in Punjab could be curbed by providing information on best practice to farmers and by realigning economic incentives away from electricity and crop subsidies and instead encouraging sustainable irrigation systems.
A locally-focused package of regulatory, economic and collective-action approaches should be introduced in areas of intensive groundwater usage. This package should support a well-defined groundwater entitlement system, incentive efficient resource use and, importantly, involve the local users. In California, the state government introduced the 2014 Sustainable Groundwater Management Act, under which local agencies are being formed that will develop regionally-specific and long-term water management programmes with defined sustainability objectives.
Groundwater has the potential to act as a natural insurance mechanism for farmers, so that they are not reliant on surface water to continue to produce in times of drought. This resource would support them in an increasingly volatile climate and allow us to keep producing the food demanded by a growing global population.
More information on the GFFA panel discussion can be found here together with a list of the speakers.
The OECD’s review of groundwater policies in agriculture, which includes 16 country profiles, can be found here
An overview of the OECD’s work on water use in agriculture can be found here.
IFPRI’s work on water policy can be found here.