Abstract in italiano

As of 2018, according to the UN, over 2 billion people were living in countries experiencing high water stress. Nearly half the global population is already living in potential water-scarce areas at least one month per year and this could increase to some 4.8–5.7 billion in 2050. On the one hand, there is a so called “triangle of thirst” that goes from Southern Spain, to Pakistan, to the Horn of Africa and back again, with around two billion people in a very water-scarce region. On the other hand, there are countries like Russia or Canada, where there is more water than they need in terms of the size of their population. This water resources disparity constitutes a problem already itself. The world is experiencing water scarcity, yet water (Figure 1) keeps being perceived as a non depleting resource.

Water scarcity describes a situation where there are insufficient water resources (Figure 2) to satisfy its long-term average requirements. It occurs when a country is faced with long-term water imbalances, meaning that there is low water availability (Figure 3) and a level of water demand that exceeds the natural system supply. At present, water scarcity is mainly assessed through the Water Exploitation Index (WEI) applied on different scales. The WEI is the average demand for freshwater divided by the long-term average freshwater resources. It illustrates to which extent the total water demand puts pressure on the available water resource in a given territory and highlights the territories that have high water demand compared to their resources.

Which are the “usual suspects”

The phenomenon has multiple causes. The most obvious one is climate change. In fact, water-related disasters such as floods and droughts have increased over the past 25 years. These events are only likely to continue with tough consequences on access to safe drinking water. This is because when disasters hit, they can destroy or contaminate entire water supplies. Moreover, resulting rising temperatures can significantly impact on the potability of water by leading to deadly pathogens in freshwater sources with hard consequences on the health of entire communities. And, similarly, rising sea levels can instead make fresh water saltier,depriving millions of people of drinkable water. Therefore, climate changes exacerbate water stress, especially in areas where resources are already low and creates the premises for increasing competition and even conflict over water resources.
In a world expected to increase by 2 billion people in the next 30 years, the situation is likely to get worse (Figure 4) As a matter of fact, a growing population translates into a subsequent rise of the demand and competition for water resources. This is an even more pressing issue given the fact that the demographic rise is coupled with an increasing urbanization. As a result, there is a considerable pressure on the need for water for domestic, industrial, agricultural and/or municipal use (Figure 5). Water is not only scarce because of its high usage, often it is also wasted in unsustainable industrial productions and inefficient agricultural practices like flood irrigation and water intensive wet cooling thermal power plants that use more water than necessary. Another example of this over-reliance on water is waste management. At present, about 80 percent of the world's wastewater is discharged back into nature without further treatment or reuse. Moreover, in many countries, it is cheaper to receive clean drinking water than to treat and dispose of wastewater. This logically encourages water waste.
As a matter of fact, the pricing of water has already been identified in general as a concern. Water is widely mis-priced. Many countries are reluctant to increase the price of water and, on the contrary, are prone to put in place “water subsidies”. Public water is often charged a fraction of its transportation and water infrastructure maintenance. Such subsidies often exceed the total public spending, leaving no resources for other kinds of investments. This misallocation has proved to be not beneficial. Usually it is aimed at helping the poorest population. However, since such subsidies are proportional to the water one uses, and since the poor often have limited or no access to water, subsidies in developing countries end up benefiting mostly upper-income groups. Therefore, they are largely inefficient. Water pricing reforms are needed in order to improve water access ratios and reduce its waste. The need for a change is also more evident in view of the fact that water scarcity is worsened by the general deplorable conditions of water infrastructures.

These infrastructures are crucial since water needs to be transported, treated and also discharged. However, current infrastructures around the world are old: most of the systems in some of the biggest cities were laid at the beginning of the 20th century and their maintenance or replacement work has often been neglected, because, they are very expensive to install and repair. Only in the USA, for example, 6 billion gallons of treated water are lost per day from leaky pipes alone. And this is also more worrisome, considering that “natural infrastructure” is not in better conditions. Healthy ecosystems act as natural infrastructures since they filter pollutants, they consist into a buffer against floods and storms, and regulate water supply. Preserving plants and trees is essential considering their role in replenishing groundwater. They are needed for rainfall to seep into the soil instead of sliding across dry land. In a world that has lost up to 22 percent of watersheds’ forests, water scarcity is bound to increase again. Furthermore, around 31% of the world’s available freshwater depends on groundwater. And the situation is not rosier for this source of water as well. Rather, according to the NASA satellite data 13 of the largest 37 aquifers in the world are considered significantly distressed. This is a consequence of growing agriculture needs for irrigation due to an ever growing world population  Therefore, water scarcity can quickly become a form of food shortage if not addressed.

Consequences of a thirsty world

There are immediate consequences to this situation. Access to clean water is crucial to lower inequalities. Not having access to water can exacerbate the realities of vulnerable subjects such as women, farmers and children. Women in poor communities are usually the ones in charge of fetching water. And for farmers their ability to meet ends entirely depends on the availability of irrigation water. In a country like India, for example, major droughts have led to farmers’ suicides and protests demanding for higher crop prices and loan waivers. If water is not available, food production is severely impacted and as a consequence poor children are not nourished properly, with long-lasting consequences for their development.
Furthermore, water scarcity directly impacts on food security (Figure 6). Currently about 70 percent of global water goes to agriculture. With a population growth and rise in household income, the demand for food is estimated to increase by 70–100 percent by 2050. Therefore, finding new sustainable ways of production and technologies will be the challenge for guaranteeing food supply. Its effects stretch also to the energy sector. Water scarcity severely impacts on energy production. Because of lack of water, power plants are forced to shift to dry cooling systems that are more expensive to build and less efficient than water-cooled systems. Moreover, due to low water flows or high water temperatures, power plants either have to shut down altogether or to reduce power generation. Also, as a consequence, often electricity production is significantly reduced. According to the International Energy Agency’s estimates, by 2035 the world’s energy consumption will increase by 35%, which in turn will increase water consumption by 85%.

This is a source of concern for the future of energy and highlights the risks of a water driven general economic slowdown as well. Sectors such as food and beverage, technology manufacturing and textiles, oil and gas sectors are severely impacted in their daily operations. For example, it takes more than 15,000 liters of water to get a single kilogram of beef if we calculate  irrigation of feeding crops, providing drinking water, and hosing down factory farms, transport trucks and abattoirs. Similarly water dependent is the textile industry: growing, washing and dyeing the cotton used to make a single pair of jeans requires 9,500 liters of water. Also the production of semiconductors requires two to four million gallons of Ultra pure water per day and it has been calculated that the oil and natural gas industry incurs in 15% water management costs for drilling and maintaining the oil and gas wells. These are concerns that need to be addressed.

The way forward

Notwithstanding the difficult challenges at play, there are solutions and some of them are already being put into place. For each one of the challenges outlined there is a solution and often solutions are intertwined as well. First of all, there are major initiatives such as Nationally Determined Contributions (NDC, post 2020 climate actions for reducing emissions based on the Paris agreement) and the Sustainable Development Goals promoted by the UN that aimed at reaching a more sustainable world (Figure 7 ). However, more specific forums for decision makers to exchange best practices on water management would only be beneficial. Furthermore, countries need to get a fair water price  and to back up this change with reforms and adequate policy reforms. Also, more money needs to go into research and innovation, to find better irrigation methods that waste less water and are more efficient and new water filtration methods. However, leaps forward in terms of policy and technologies must be accompanied by education efforts to change our lifestyles and make them more sustainable. The battle against thirst is on, and the way to a solution long.