Even though
most of us know that water is an integral part of food production, many of us
are not aware of the relationship between water scarcity and food security. Why
is water so fundamental? Before proceeding onto later blog posts, I would like
to remove the many misconceptions about water and food that we may have.
Initially, before
starting my geography degree at university, I would stare into the depths of
the ocean whenever I visited the beach and I would ponder why countries could
not access this water for drinking and why so many areas had water shortages.
After all, our earth’s hydrosphere contains 1386 million cubic kilometres of
water; it is the most widespread substance on our planet (Shiklomanov 1998). Most importantly however, only 2.5% of this is
freshwater and 97.5% is saline (ibid).
To make matters worse, from the little freshwater available, 68.7% of it is
locked up as ice in the Arctic and Antarctic regions (ibid). The distribution, state and salinity of the water are all
factors shaping who has access to water.
Exponential
population growth has been significant in shaping the demand for water throughout
our world. As the world’s population grew between 1970 and 1994, it was
estimated that the potential water available per person per year fell from 12.9
down to 7.6 thousand cubic metres (ibid). This statistic is all the
more relevant for my blog’s focus on Africa, as the continent experienced the
greatest reduction in population water supply throughout this time (ibid).
Water Scarcity
I hope the
above information sheds some light onto the weight and relevance of the word ‘scarce’
when we are talking about water scarcity and why such an indicator is
necessary. Water scarcity can be broadly defined as the ‘shortage in the
availability of renewable freshwater relative to demand’ (Damkjaer and Taylor 2017: 513). However, there have been attempts at designing a more robust
metric. The Water Stress Index (WSI) developed in the 1970s and 80s defined
water scarcity as ‘the number of people that compete to be sustained by a
single flow unit of water’ (ibid:
514). The Water Stress Index proposed by Falkenmark in 1989 evaluated the
thresholds at which different levels of scarcity occurred (Brown and Matlock 2011).
Table 1: The Water Stress
Index (Brown and Matlock 2011).
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Table 1
outlines these thresholds; a country which is only able to supply under 500m3
of water per person per year is said to be experiencing ‘absolute scarcity’. It
has been a popular indicator and has been widely used because it is easy to
calculate and interpret (Herath
et. al. 2010; Gleick et al. 2002).
Figure 1: A map of water
scarcity in Africa in 2014, using the Water Stress Index (Damkjaer and Taylor 2017).
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Let’s take a
moment to observe Africa as a whole. Figure 1 highlights an interesting distribution
of freshwater, whereby countries towards the north and south are experiencing
greater water scarcity such as South Africa, Libya and Algeria. However, when compared
to other indexes of water scarcity, whether this data is meaningful falls under
question (Damkjaer and Taylor 2017). This is because the Water Stress Index
proposed by Falkenmark has a number of major limitations; the values are skewed
due to spatial and temporal factors.
Limitations:
- The values are national annual averages which means that unique data at regional levels on a smaller scale has been ignored (Brown and Matlock 2011).
- The annual average will ignore any seasonal variation which is significant due to the dry and wet seasons caused by the ITCZ in the area.
- The thresholds themselves are too simple as they ignore cultural and lifestyle differences, which will mean demand will vary from country to country (Rijsberman 2006).
- Leading from the above limitation, these thresholds are static and do not represent the changing dynamics and demands of the future, as our technology advances (Brown and Matlock 2011).
- Artificial water supplies from desalination plants are overlooked (Damkjaer and Taylor 2017).
An indicator
which attempts to resolve these limitations, by taking artificial sources into
consideration for example, is physical and economic water scarcity (Damkjaer and Taylor 2017). Adaptive capacity, a concept which will be explored in greater
depth in my next blog post, is what determines whether a country is
economically scare or physically scarce. There are many other metrics to be
aware of, some of which are holistic:
- Social Water Stress Index
- Agricultural Water Poverty Index
- Basic Human Needs Index
- Water Poverty Index
- Watershed Sustainability Index
- Canadian Water Sustainability Index
Another widely
held misconception is that most of our water is used for the purpose of
drinking. In fact, as discussed in the video, agriculture is the biggest
consumer of water which accounts for 70% of all withdrawals (FAO 2011). Even
though a lack of access to clean drinking water is a major problem in Africa,
on average a person is only required to drink 2-4 litres a day. This is compared
to the 2,000 to 5,000 litres of water required to produce a person’s daily food
intake (ibid).
This blog post is necessary in order to put my future blog posts into context. Hopefully I’ve given you much food for thought, no pun intended.
This blog post is necessary in order to put my future blog posts into context. Hopefully I’ve given you much food for thought, no pun intended.
List of
references
Brown, A.
and M. D. Matlock (2011) ‘A review of water scarcity indices and methodologies’,
White paper, 106, 19.
Damkjaer, S.
and R. G. Taylor (2017) ‘The measurement of water scarcity: defining a
meaningful indicator’, Ambio, 46,
513-531.
FAO (2011) Water
at a Glance: The relationship between water, agriculture, food security and
poverty.
Gleick, P. H.
Chalecki and A. Wong (2002) ‘Measuring Water Well Being: Water Indicators and
Indices’, in P. H. Gleick, W. C. G. Burns, E. L. Chalecki, M. Cohen, K. K. Cushing,
A. S. Mann, R. Reyes, G. H. Wolff and A. K. Wong (eds.), The world's water, 2002-2003: the biennial report on freshwater
resources, London: Island Press, 87-112.
Herath, I.
K., B. Clothier, and D. Horne (2010) Indices of the status of freshwater resources
for impact analyses, in: Proceedings of the 19th World Congress of Soil
Science, Soil Solutions for a Changing World, Brisbane, Australia, 1–6.
Rijsberman,
F. R. (2006) ‘Water scarcity: Fact or Fiction?’, Agricultural Water Management, 80, 5-22.
Shiklomanov,
I. A. (1998) World water resources. A new appraisal and assessment for the
21st century, Milton Keynes: UNESCO.
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