We are no strangers to the term "carbon footprint", which is now universally recognised and frequently used in discussions on sustainability. However, another less-discussed aspect of humanity's impact on the environment is its water footprint. A water footprint measures the amount of water used to produce each of the goods and services an individual uses. This can be used to measure a process, such as growing crops, or a product, such as a phone. It also gives us an idea of how much water each country consumes, and for what purpose.
What is the "Water Footprint" concept?
The water footprint is a concept that was introduced in 2002, to measure water usage. It is made up of three elements:
1)
Green Water consists of the rainfall on land that is stored in the soil and evaporated, transpired or incorporated by plants.
2)
Blue Water refers to fresh surface water and groundwater. This consists of lakes, rivers and aquifers.
3) Lastly,
Grey Water is the volume of freshwater required to assimilate pollutants in order to meet specific water quality standards.
The water footprint model helps us identify the human impact on freshwater systems. By understanding how our behaviour affects the environment, we will be better-equipped to address issues such as water shortages and water pollution. It also allows us to observe consumption patterns and how they can be tweaked to ensure greater sustainability.
For example, one of the main arguments against the consumption of beef, is that it uses approximately 15,000 litres of water for merely one kilogram of meat. Most of this water goes into watering the feed and grass required to grow cattle. The inefficacy of water usage in producing meat becomes overwhelmingly obvious when compared to the average of 322 litres for one kilogram of vegetables, or 4,055 litres for a kilogram of pulses. Reducing meat consumption or switching to a vegetarian diet could lessen an individual's water footprint by up to 35%.
On a bigger scale, when we compare the water footprint of different countries, we also get an interesting idea of how consumption patterns affect water usage. The United Kingdom (UK), for example, has an average water footprint of 2,757 litres per person per day, compared to 3,861 in France. One of the simple reasons for this is that the French drink more wine, which has a higher water footprint than beer, the preferred choice of beverage of the British.
How useful is the Water Footprint model?
The water footprint model firstly allows countries to use water sustainably according to their needs. As Dr Joost Buurman, Senior Research Fellow at the Institute of Water Policy, Lee Kuan Yew School of Public Policy, explains, "In an area with lots of rainfall, the green water usage in crops would automatically be higher, while in dry areas crops would require more irrigation, and hence blue water."
In theory, this works well if blue water is sourced sustainably. However, if it is not, then it can cause much bigger problems. Dr Buurman cites the Aral Sea as an example of unsustainable water use. Once the fourth-largest freshwater lake in the world, inefficient blue and grey water use for cotton production led to the shrinkage of this water body down to a tenth of its former size. This has led to the decimation of the fishing industry, and consequently a huge adverse effect on the local economy. This cautionary tale reminds us inefficient water usage can seriously threaten water security.
In general, we should be aiming to use less resources per person in order to achieve sustainability. More people are beginning to understand this, as can be seen from changing consumption patterns. Meat alternatives such as Beyond Meat and Impossible Foods are becoming increasingly popular as more people attempt to adopt a more plant-based diet.
However, as Dr Buurman explains, when it comes to water consumption, it is not as simple as merely reducing how much we utilise. One also needs to think about equitable water usage, or how water resources can be distributed fairly. Dr Buurman states the importance of considering the local context, as "it does not make sense to use expensive technology to use less water in places where abundant water is available and sustainable extraction is possible."
Heineken, for example, has a 2030 water vision in support of the United Nations Sustainable Development Goals. The company has recognised that it is important to have a highly contextual approach to the specific area the water resource is located in.
Instead of merely reducing water usage, Heineken has chosen to focus on the reuse and recovery of water, and to work collaboratively with other users of the watershed so that its health is protected and surrounding communities can continue to thrive. Some of its collaborations include investing in rainwater harvesting projects in Malaysia, and the installation of "biopori" holes in Indonesia, which slow rainwater runoff and preserve water.
Policy Considerations
A study done by the Netherlands Environmental Assessment Agency highlights the limitations of the water footprint model, as from a policy perspective its components are inconsistent and cannot be compared against each other. For example, green water represents water uptake by crops, which in reality may not be so different from the uptake by natural vegetation, while blue water represents direct human intervention in the water cycle. This would make the model unable to reflect actual environmental impact.
However, the water footprint model could still be a useful tool for policymaking if, as mentioned, one also considers the local context and issues such as water scarcity and pollution. Much like carbon footprint policies, a system of water footprint caps per water body could possibly be introduced. To ensure an equitable distribution of water, certain minimum amounts could be allocated to allow for local basic needs in production. The remaining food imports could then be obtained from sustainable sources.
Dr Buurman also suggests solutions to increase water efficiency such as the usage of drip-irrigation technology in agriculture, which is a system that can save water and nutrients by allowing water to drip slowly in close proximity to plant roots. Other options also include water taxes, extraction permits, and monitoring pollution standards. He does point out, however, that this might affect production, and hence has an economic cost.
On a global level, there could be a concerted effort to rearrange worldwide production and trade patterns to reduce pressure on water resources. Efforts could also be ramped up to educate the public on how to choose products with smaller water footprints. Companies could also potentially use the water footprint model to trace areas in their supply chains that need to be improved.
Ultimately, Dr Buurman says that "Water footprints are good in raising awareness among business and individuals about how our consumption patterns may cause unsustainable water use globally." To change global patterns of water consumption, reducing unsustainable water use should first be achieved at a local level, by considering circumstances unique to each region.
(Photo credit: PS Photography)