2. A Critical Look at Measuring Water Scarcity

Following last week's post on adopting a more critical lens, I thought it prudent to examine how exactly we measure water scarcity, as well as investigate the political implications of relying on various indicators such as the Water Stress Index (WSI). 

Everywhere we look, there is much talk of a water crisis. One statistic that gets thrown around a lot is the line "water scarcity affects 1 in 3 Africans" (WHO 2021), but what exactly does this mean? 

According to the WSI, otherwise known as the Falkenmark Indicator, water scarcity is determined by the volume of renewable freshwater available to each person living within a given spatial domain per year (Falkenmark 1989). A country is said to be facing water stress if the volume of renewable water in a country is below 1700m3/person/year, while a volume below 1000m3 would indicate water scarcity (Falkenmark et al. 1989). Failing to meet these thresholds would therefore suggest that a country is struggling to sustain a healthy and active life for its citizens. Borne out of a need to investigate the links between water scarcity and famines in the Sudano-Sahel in the 1980s, the straightforward and easily interpretable WSI is now the most widely-adopted metric for measuring water scarcity (Damkjaer and Taylor 2017). 

Despite its merits, the WSI is unfortunately also riddled with substantial flaws that render it a misrepresentation of water scarcity. One major limitation is that it operates on the assumption of universality, imposing the same numerical thresholds on countries that in fact have different water demands (White 2014). Globally, roughly 70% of all freshwater withdrawals is used for agriculture and 20% goes to industry; yet the WSI ignores these major uses and assumes that the 10% going to households represents the full picture (Calzadilla et al. 2009). Furthermore, using the WSI also suggests universality within nations themselves, masking local inequalities and thus slighting the political geographies of uneven access to water. 

Figure 1: Map of water scarcity in African nations, as defined by the WSI (Damkjaer and Taylor 2017)

Another shortfall is that the WSI equates access to safe drinking water to freshwater availability, failing to acknowledge the myriad other factors like management practices and quality of infrastructure (Liu et al. 2017). This gap explains the observed lack of correlation between the WSI and actual access to safe drinking water. To illustrate, Figure 1 shows that Morocco and Egypt are facing water stress or scarcity, and yet over 90% of their populations have access to safe drinking water (Damkjaer and Taylor 2017). This effectively demonstrates how metrics such as the WSI fail to account for the political nature of water scarcity, instead presenting it as an issue of physical availability. 

Evidently, the WSI is inherently limited, and other metrics have their fair share of problems too. These metrics play a crucial role in informing policies that govern water resources - they have the power to represent and misrepresent realities and it is hence crucial that they are critically examined, instead of being taken at face-value.

The next time you see a headline screaming "45% of Africa is under water stress", remember to think twice about what it really means!