Three’s a Crowd? A Global Look at Water, Food and Climate


12 July 2011 | Fernando Miralles-Wilhelm

Greetings my dear readers, I hope you are doing well wherever you are. I am on vacation at this time, but I am one of those people that cannot separate from work for too long, so here goes another blog post so we can chat through this medium. I’ll go a bit deeper into details of my personal life, that although may not be of interest to anyone but myself (ouch!), it has always been the main source of ideas for me as a researcher and practitioner.

I married into a “cattle family”, where my wife’s father was a cattle farmer, and her two brother’s have kept on with the family tradition. Moreover, probably every male cousin of my wife (the many she has) are in the family business. When we go to visit the family in Venezuela, my brothers in law enjoy taking the “gringo” to the ranch for an outing (they say it’s good to get me away from my computer). Being a total “urbanite”, this has always been something I look forward to, because there is always something new for me to learn.

Something that caught my attention time and again during these trips out to the country was the vast amounts of water used in meat production at their farm, as well as that used for irrigation in other farms in the surroundings. This part of Venezuela (south of Lake Maracaibo) has extremely productive soils and farming is a formidable source of economic activity.

As a hydrologist dabbling in climate change, I have become convinced that adaptation to climate change has a lot to do with water and how we use it. Primarily because water is not only part of climate itself, but also part of pretty much any human activity in this planet. Think about it: our industries, our energy, and yes, our food security, are intimately tied to water. So, water is a natural “bridge” to understand how changes in climate can affect our different activities, and more importantly, water needs to be a part of any workable adaptation strategy to cope with climate change.

This is why I read with great interest a recently published research paper on the “global virtual water” trade network.

In this paper, the authors analyze the trade of food among 166 nations, and quantify the size (footprint) of the “virtual water” around the world, this is, the amount of water that is used to produce the food that is traded between these nations. This virtual water trade network is useful because it gives us an idea of the amounts of water that are really used by each nation when considering their food supply; it also provides a means to understand where that water is coming from.

One of the interesting results of the investigation, and one that is perhaps not too surprising is that “This analysis provides evidence for the existence of the weighted rich club phenomenon, where a tightly clustered group of countries trade the majority of the resources among themselves… major exporters preferentially trade large volumes of virtual water with one another.” For me, the interesting part of this analysis is that the authors have actually crunched the numbers of volumes of water that flow through different parts of the network, so we can make concrete comparisons and now there is a baseline to study the exchange process in more detail.

Although the concept of virtual water is nothing new, what this investigation does is that it allows us to look at the trade network of water, and how much water moves where for the purpose of trading food. I have discussed this paper with the authors, and they have told me that they are now working on analyzing the change of this network over time (for last 30 years) and how the volume of traded water in the network (the size of the arrows in the map) changes with different climate, policy and population scenarios.

I have invited them to give us a talk at the IADB, and when this happens, we’ll webcast it for anyone of our readers who is interested. This certainly looks like an important tool we could have to improve our understanding of the impacts of global change in our region, and arriving at workable adaptation strategy to reduce our vulnerabilities.

You can find a full copy of the paper here.

A version of this post in Spanish can be found here.


The blog was originally posted on IDB: Let's Talk Climate Change. To read the original blog, click here.