Climate change and it’s relationships to technology, energy and food are often discussed in the media, whereas freshwater, also a critical resource for humanity, tends to be overlooked. It is even more overlooked in terms of other species – lakes and other surface waters provide homes for hundreds of thousands of species. A recent article reviews freshwater and its linkages to food and energy, and describes the complex trade of “blue water” and “green water.”
By Frank Götmark
Broad review articles in science are often valuable. Paulo D’Odorico and his co-authors published one such article in 2018, “The global food-energy-water nexus”, describing global freshwater availability and its relation to food and energy production . Many people, though far from all, take freshwater as a “given”. However, it is an important part of our lives that may limit us as a species, especially in the future. Overconsumption of freshwater also threatens other species: lakes, rivers and wetlands are the most threatened habitats on earth, with the highest proportion of red-listed species of all habitat types [2,3].
There is much water on Earth, but the production of freshwater from saline and brackish water requires at least 10-12 times more energy than freshwater treatment, according to the review. Desalinated water is basically only used for drinking, in a few countries such as Saudi Arabia and Israel that can afford to produce it. The authors divide freshwater into “blue water,” i.e. surface waters and groundwater aquifers, and “green water” which is soil moisture in the ground, to be used by green plants, fungi and other organisms.
People associate freshwater with drinking, washing, shower-baths and water for gardens, but agriculture is the biggest user, accounting for 86% of total human water consumption . The majority of freshwater that we don’t see is in our food, consumed far away from the production sites. To produce food, countries (especially the US, India and China) often use blue water for irrigation; 20% of global agricultural land is irrigated, but such land has higher yields and sustains about 40% of global crop production. Green water is required for agriculture, too. Limits to both water types can be seen when rivers run dry, immense lakes like the Aral Sea and Lake Chad disappear, salt water encroaches into coastal lands (such as the Nile delta and the Gaza Strip) to replace the fresh water pumped out, and in periodical regional droughts and crop failures. The “Green Revolution” seems to be history: agricultural yields are stagnating . Limited freshwater availability is one cause. Major food crises occurred in 2008 and 2011. Between 2005 and 2008, food prices increased by 83%, which pushed about 40 million people into hunger. As I write this, the media is reporting a severe water scarcity in India, affecting about 100 million people .
Freshwater we don’t see is also in the energy we use, far away from the production sites. D’Odorico and his co-authors describe in detail this “hidden” freshwater use. Oil extraction, coal mining and biofuel production all require immense amounts of freshwater. The unconventional fossil fuels, such as shale oil, gas and oil sands, are especially water-demanding. In the case of biofuels (maize, sugarcane, palm oil), production competes with food crops and green water, commodities that are greatly needed locally and nationally.
The overconsumption of freshwater is further clarified when the authors describe global trade. A “virtual water” transfer of blue and green water through trade of energy, food, and other commodities such as timber, means that countries with a chronic scarcity of water will import products that they cannot produce themselves. Increasing trade allows the continued harvest and extraction of natural resources – at the cost of species extinction and increasing emissions of greenhouse gases. Virtual water trade of agricultural commodities more than doubled between 1986 and 2010, and plant material dominated this trade by volume. At the global level, about 24% of the water used for food production is now traded. The authors remark that “the globalization of water for food and energy security remain overall poorly understood, and it is unclear whether trade will generally act as a buffer against, or an intensifier of vulnerability for nations relying on food imports.”
As long as humanity can secure food and other commodities for most nations through cheap energy and trade, the global population may continue to increase – by about 3.5 billion people to 2100, according to the UN’s 2019 population projections’ medium variant. However, the UN projections assume continuously falling fertility rates. With slower declines, several more billions may be added. In this context, D’Odorico and his co-authors compare a nation which is self-sufficient in terms of water, food and other resources, with an ecological footprint wholly contained within its borders, and a nation where significant international trade creates both internal and external footprints, in this way:
In a) above, a country uses resources (water, food, etc) that occur within its border only; in b) a country uses resources within as well as outside its border – through trade. One may object that a) can no longer exist because people want or need so much from the “outside.” But self-sufficiency of nations was much discussed not long ago (in the 1960’s and 1970’s). For instance, the ecologists Anne and Magnar Norderhaug (1974) calculated that Norway essentially could achieve self-sufficiency at a level of 60% of its population at the time and level of technology and resource use . Despite a small population in 1974, without imports it would have been limited by little productive agricultural land. Although it may be a bitter cure, national policies that emphasize self-sufficiency are likely to stabilize populations sooner than policies that rely more on trade.
Self-sufficiency relates to protectionism, an idea that many politicians and neo-liberal economists dislike. Colin Hines  turns it into something positive, “Progressive Protectionism,” which he describes as a shift away from open markets to allow countries to take back control of the scale of capital, goods, services and people entering and leaving them. Hines suggests this is not possible for a single country, but could work for alliances of countries, like the EU. He concludes: “Any one country proposing controls on its own would immediately be punished by the markets. However, a regional grouping of powerful states such as the EU or North America would be a secure and lucrative enough market.”
Early in their text, D’Odorico and co-authors describe the problems with water and resource use caused by increasing numbers of people. They rightly point out that “demographers typically do not account for the effect of resource limitation” when they run population projections. Here they also cite Warren (2015) who suggests, pessimistically but perhaps realistically, that the size of the future human population will be determined by food availability (which depends on the availability of freshwater). Warren assumes, like Malthus more than 200 years ago, increasing mortality in the human population as food becomes scarcer, just like in wild animals. Today we may assume that climate change will be a limiting factor through food and water availability for human population– a factor left out from population projections.
With this background, one would have liked to see at least a brief overview on how to reduce population growth, and the advantages of declining populations. Instead, after 35 pages, the authors write: “When a society has limited access to a vital resource such as water, it can either decide to use it more efficiently by reducing waste or other losses, and/or try to import water from somewhere else.” Like many articles which describe that further population growth is problematic, this review fails to acknowledge how future population growth can be minimized. Family planning programs, and changes in social norms that influence fertility rates, should have been described. In their Abstract and conclusion, the authors emphasize a circular economy (reusing the resources in products to create new products), but the circular economy’s requirement for a stable population is not discussed.
Still, the review contains a plethora of interesting information and references. For instance, the Figure 23 shows population change up to 2070 with trade for three net exporter and four net importer countries, compared to self-sufficiency. In the immediate future we will certainly have population growth, and the authors point to innovations that could improve water and food security. When it comes to feeding a larger future population, there is much more to consider, and we will come back and discuss that in a coming TOP blog.
Click here to get the review by D’Odorico et al. for free – though remember, the energy needed for the internet also requires freshwater.
I thank Malte Andersson and Jane O’Sullivan for comments and suggestions that improved the text, and Paulo D’Odorico for kindly sending us Figures from the article.
References and notes
 D’Odorico, P., Davis, K. F., Rosa, L., Carr, J.A., Chiarelli, D., Dell’Angelo, J., et al. (2018). The global food-energy-water nexus. Reviews of Geophysics, 56, 456–531. https://doi.org/10.1029/2017RG000591 (Open access)
 McRae, L. et al. (2017) The Diversity-Weighted Living Planet Index: Controlling for Taxonomic Bias in a Global Biodiversity Indicator. PLoS ONE 12(1): e0169156. doi:10.1371/journal.pone.0169156 (Open access)
 WWF (2018) Living Planet Report – 2018: Aiming Higher. Grooten, M. and Almond, R.E.A. (Eds), WWF, Gland, Switzerland (Open access)
 See Ray & Foley (2013), and articles by Ray et al. – see references in .
 Aljazeera (2019), June 20. “India is running out of water, fast”. https://www.aljazeera.com/news/2019/06/india-running-water-fast-190620085139572.html  Norderhaug, A. & M. (1974). Norge og overbefolkningen. Cappelen. (Only available in Norwegian.)
 Hines, C. (2017) Progressive Protectionism: taking back control. Park House Press. Kindle Edition (ebook)
Do you want to learn more about the solutions for overpopulation and actions towards sustainability? What actions we need to take on individual, community, national and global level? Check out the Overpopulation Project’s list of solutions!