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Green Water and Sustainable Agriculture

Worldchanging guest writers David Zaks and Chad Monfreda are graduate research assistants at the Center for Sustainability and the Global Environment at UW-Madison where they work on understanding how human activities affect the biological and physical systems of our planet.

greenwater_diagram.jpg If green is the new black, then water is the new oil. With climate change threatening harsher droughts and water scarcity facing nearly 60% of humanity, water is critical to any vision of sustainability.

Water scarcity is a major issue for rainfed agriculture, which uses 75% of all agricultural water. Rain-fed agriculture is at the mercy of two things: rain and the capacity of soil to capture and store that rain. While farmers can't do much to make it rain, they can do a lot to retain rainfall in the soil. The rainfall that infiltrates and remains in the soil--also called green water--is the largest fresh water resource and the basis of rain-fed agriculture.

Green water is a very important resource for global food production. About 60% of the world staple food production relies on …  green water. The entire meat production from grazing relies on green water, and so does the production of wood from forestry. In Sub-Saharan Africa almost the entire food production depends on green water (the relative importance of irrigation is minor) and most of the industrial products, such as cotton, tobacco, wood, etc. (link)

Payments to farmers in the developing world are one opportunity to improve water management, while at the same time alleviating poverty and ensuring the flow of ecosystem goods and services like flood control and healthy soil. Modest measures like mulching, conservation tillage, and small-scale water harvesting can increase infiltration by as much as 2-3 fold. Other methods include terracing, contouring and micro-basins that also increase green water and reduce run-off. You'd think that development agencies would be clamoring to invest in these simple but effective techniques, but...

Green water is ignored by engineers because they can't pipe or pump it, by economists because they can't price it, and by governments because they can't tax it. (link)

Instead development agencies have traditionally favored 'blue water,' which refers to all of the rainwater that does not stay in the soil as green water but enters rivers, lakes, and groundwater. If you're an engineer, economist, or government official, blue water investment in costly irrigation networks may make sense, but if you're a farmer loosing precious rainfall from your land it surely doesn't.

Green water credits, however, are an opportunity to address this disparity while enhancing ecosystem services for both farmers and downstream stakeholders. The International Soil Reference and Information Centre (ISRIC) is pioneering green water credits, which it describes as:

A mechanism for direct payment to people in rural areas in return for water management activities which are presently un-recognized and unrewarded. Benefits to poor people drive this initiative which, at the same time, safeguards water resources and food security for everyone.

With funding from the Swiss Agency for Development and Cooperation (SDC) and the International Fund for Agricultural Development (IFAD), ISRIC is developing a proof-of-concept project that creates financial incentives for farmers in the developing world to better manage green water. ISRIC is taking three steps to implement green water credits:

1. Quantification of the resource and how it can be optimized by land use and management;

2.Valuation of its various uses and the costs of floods, sedimentation, and the diseases caused by a lack of clean water – enabling benefit cost analysis;

3. An agreed mechanism to:

    a. Specify optimum management and its water benefits;

    b. Negotiate a fair price;

    c. Establish that the work is done;

    d. Collect and pay credits. (link)

ISRIC will assess the feasibility of green water credits in sub-Saharan Africa and subsequently test them in major river basins. If all goes well, they will roll out the initiative globally.

Although ISRIC's starting funds come from development agencies, green water credits are not charity but an investment expected to yield returns greater than traditional large-scale, blue water projects. If it demonstrates that green water credits are viable, international finance mechanisms like debt swaps will need to jump-start the process. In the longer term, local utilities and water users are likely to be the primary funders. Flood insurers might also fund the credits, as green water conservation mimics the buffering effect of natural vegetation, thereby mitigating the risk of flooding for people downstream. There's no reason, however, that finance couldn't take more innovative channels. The small-scale of green water investments make them ideal for distributed, collaborative microloans that altogether bypass large funding agents.

Poor farmers already know how to improve rain-use efficiency but lack the resources to do so. As an investment in local knowledge green water credits ultimately promise more than green water. They leverage existing social capital to bring rural farmers out of poverty and reduce the negative externalities of poor land management. "Good husbandry of green water means good land husbandry" that slows erosion and builds soil fertility. Green water benefits downstream users too. When more water infiltrates into the soil, less pesticide, sediment, and fertilizer enter waterways. This translates into higher quality water for domestic and industrial use and less dam-clogging sediment.

Water scarcity is not only about water, just as hunger is not only about food. Green water credits are a solution that takes a systems perspective to approach water, hunger, climate, and poverty together.

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Comments

Very interesting post. Keep 'em coming, David and Chad!


Posted by: Ryan on 26 May 06

Excellent post, guys. These posts from David & Chad have been really interesting. Please keep them coming!

This idea is really worth exploring: how do we improve water flows, while simultaneously improving the resilience of people and ecosystems.

I wonder: would increasing proper vegetation cover and organic matter in soils be the key for this?

Also, what about ways of restoring nutrients (especially nitrogen) to the soil at the same time? Legumes, anyone?


Posted by: Andrew J. on 27 May 06



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