What should sustainability professionals know before applying their carbon backgrounds to learn about water sustainability?

After oxygen, water is arguably the most fundamental substance for human life. Unfortunately, population expansion, industrial growth, and climate change among other factors are exerting pressure on this crucial resource. Per United Nations estimates, half the world’s population will be living in water stressed areas by 2030. Often misunderstood is that many of those areas are situated in densely populated Europe, Southeast Asia and the US. Other studies project water shortages in the United States around the Great Plains, the Southwest and much of the country’s coast over the rest of the 21st century.

Water scarcity is rapidly becoming the top concern across Europe, Asia and the US. Coupled with the historical lack of needed investment in infrastructure, scarcity has pushed water prices to rise. Water bills have increased by over 30% in the past 10 years and are expected to continue to rise. For an increasing number of organizations, water sustainability is not just a matter of good environmental stewardship. It is also an essential path to increased resilience, efficiency and cost savings.

Those working on these efforts must develop an understanding of water sustainability. Sustainability professionals without water background can build their water knowledge through an analogy to a more developed field: greenhouse gas (GHG) accounting.

Dimensionality

GHG accounting is relatively direct. Seven GHGs are commonly tracked: methane, sulfur hexafluoride, carbon dioxide, perfluorocarbons, nitrogen trifluoride, nitrous oxide, and hydrofluorocarbons. But all gases are grouped together under a single unit: carbon dioxide equivalents. GHGs can be considered a one-dimensional concern.

By contrast, water sustainability is often multi-dimensional. Depending on the region, the entity and other situational specifics, water concerns can include:

While different concerns may be important for different organizations, the most commonly of interest for customer-facing companies are scarcity and quality. Water scarcity deals with how much water is used or consumed. Water quality deals with the purity of water used and how that purity changes during use.

In short, GHG efforts relate to a single tracking unit while water efforts can relate to several factors, but especially to water scarcity and water quality.

Essentiality

An organization’s GHG emissions are generally other activities’ byproducts or the result of natural processes. For example, GHGs are formed by combusting fossil fuels in energy generation. The combustion’s purpose is generating heat energy not the creation of GHGs. GHGs are a result of the process, but the GHGs would not be missed if the heat could be generated without GHGs. This holds true for most processes that create GHGs.

By contrast, water use can be a byproduct, but water use is also often the activity’s purpose. For example, water is used on farms for irrigation. The goal of this process is for plants to consume water. While the amount of water used for irrigation can be reduced, water is necessary for irrigation. Additionally, in this example water cannot be reclaimed or reused. In other processes, water can be recycled so overall use is reduced. Many processes require some amount of water. In processes for which water quality is a factor, efficient reuse can be further limited.

To put it more plainly: For many GHG reduction efforts, GHG emissions can be reduced to zero; For most water reduction efforts, the amount of water consumed must be higher than zero.

Regionality

In GHG accounting, organizations can consider GHG reduction efforts globally. Locations may have different laws about GHG emissions, but once released, GHGs exist in the atmosphere. After following local laws, organizations can choose where within their operations to reduce emissions. GHG emissions are a global concern.

On the other hand, organizations must consider water sustainability regionally. Each region has its own water supply. Regional water supply is based on natural processes (rainfall, snow melts, groundwater recharge, etc.), and geography (both natural and artificial). Water is dependent on natural systems in a way comparable to renewable energy, especially solar and wind.

However, water and renewable energy have two key differences. Water is 1) easier to store, but 2) harder to transport over large distances. While current battery limitations restrict renewable energy storage, municipalities control availability of water by storing in reservoirs and actively managing groundwater levels. Conversely, modern grids allow electricity to travel long distances between where it is produced and where it is consumed. Long range water transportation is much more limited due to energy, infrastructure, and legal requirements. This means that each region must actively manage its own water resource.

For good stewardship and effective resilience, water sustainability plans must be deeply tied to each region of operations – net sustainability across regions is not applicable. Further, an organization working in two regions can have water quality concerns in one region, but water scarcity concerns in another. Organizational efforts to address these issues must consider the region’s specific challenges.

Temporality

Related to the Regionality point above, water depends upon natural cycles. Water’s availability changes both in regular cadences (rainy seasons, hot weather in the summer, etc.) and in chaotic periods within those cycles (unexpected droughts, hurricanes, etc.). Water’s value increases when water supplies are scarce and decreases when it is abundant. And though water’s value fluctuates, the cost varies less with these cycles.

Typically, emitters of GHGs (fossil fuels, refrigerants, animals, etc.) are more controllable. They can, to a larger degree, be released from temporal fluctuations (outside of the normal carbon cycle).

Water sustainability plans are often driven by cyclic and other more unpredictable variations in water supply and quality within each region of operations.

Constancy

Finally, a positive point of comparison between GHG accounting and water sustainability. Burning fossil fuels is the most common source of GHGs. This is a one-time activity that chemically changes the fuel and results in GHG creation. While there is currently a wide field of study related to capturing and reusing GHGs, GHG emissions can be generally considered a one-time event.

By contrast, water typically stays the same chemically before and after its use. Water’s location and/or its quality is instead what changes. (Unless you’re breaking the molecule apart, H2O remains H2O even if contaminated, incorporated into a cell structure, etc.) This has implications for water sustainability strategies, especially for processes that only affect water quality.

In summary, professionals with expertise in GHG accounting can use that area as a basis to develop water sustainability knowledge. However, GHG accounting principles cannot be indiscriminately applied to water sustainability. Instead, any sustainability program expanding from a GHG focus to include water sustainability topics should consider the key distinctions between those areas.