A new study published in Science (I link it here) sheds light on a water crisis of unimaginable proportions. According to researchers, 4,4 billion people (more than half the world's population) do not have access to safe water resources. A number that doubles previous estimates and raises disturbing questions about global drinking water management.
An alarming discrepancy in estimates
The study, conducted by an international team of researchers, calls into question previous UN estimates. While the Joint Monitoring Program for Water, Sanitation and Hygiene (JMP) of WHO and UNICEF had estimated in 2020 that 2,2 billion people did not have access to safe drinking water, this new research nearly doubles that number.
Esther Greenwood, a researcher at the Swiss Federal Institute of Aquatic Science and Technology and co-author of the study, doesn't mince words:
There is an urgent need for the situation to change.
Water resources: safe or not? Methodologies compared
The discrepancy between the two estimates raises questions about the methodology used to assess access to safe water resources. The JMP it based its estimates on aggregate data from national censuses, reports from regulatory agencies and service providers, as well as household surveys.
The new study, however, used a different approach. The researchers analyzed survey responses of 64.723 households in 27 low- and middle-income countries between 2016 and 2020. They then trained a machine learning algorithm, including global geospatial data such as regional average temperature, hydrology, topography and population density.
Criteria for safe drinking water
Both studies used criteria established by the 2015 UN Sustainable Development Goals to define safely managed drinking water sources. These must be:
- Constantly available
- Accessible where a person lives
- Free from contamination
However, while the JMP looked at at least two of the three criteria in a given location and used the lowest value to represent the overall quality of drinking water in that area, the study published in Science categorized a household as water-deprived safe to drink if it did not meet even one of the three criteria.
It makes more sense, if you consider the data in hand about half of the 4,4 billion people without access to safe water resources are using sources contaminated by the pathogenic bacterium Escherichia coli. This data highlights the importance of paying more attention to water quality, as highlighted by Chengcheng Zhai, data scientist at the University of Notre Dame.
Because in this story "data" is everything
A major obstacle in assessing access to safe water resources is the lack of comprehensive water quality data. Greenwood points out that there is currently data on water quality for only about half of the global population. This lack of information makes it difficult to calculate the exact scope of the problem.
As he states Robert Bain, statistician at the UNICEF Regional Office for the Middle East and North Africa:
Whatever number you are working with (two billion or four billion) the world still has a long way to go.
The study highlights the need to intensify efforts to improve access to safe water resources, especially in regions such as South Asia and sub-Saharan Africa, where almost half of the 4,4 billion people without access are concentrated.
Water resources: towards a more accurate understanding
While the debate over the accuracy of different estimates continues, it is clear that further efforts are needed to improve the collection and analysis of water quality data globally. Only with a more accurate and complete understanding of the situation will it be possible to develop effective strategies to address this global water crisis.
The research published in Science not only highlights the severity of the problem, but also highlights the urgency of concrete actions to guarantee the fundamental human right to safe drinking water. With 2030 fast approaching, achieving the UN's Sustainable Development Goal of ensuring universal access to safe drinking water increasingly looks like a formidable, but absolutely necessary, challenge to address.
