Sustainability is very important in both earth system
sciences and global development. Water is a renewable source that transitions
between many phases of the water cycle, however this consistent supply of
freshwater can be interrupted if water is not consumed sustainably. Thus the
sustainable consumption is crucially important for supporting human life and
development.
A study by Wada & Bierkens (2014) explores global freshwater
use over a historical period and for future projections using the blue water
sustainability index. Results have shown that globally, there have been increases
in water consumption of non-sustainable surface and groundwater resources since
1960. In 1960, approximately 20% of human consumption of blue water came from
non-sustainable resources (surface and groundwater), however this value
increased by 50% by 2010 (Figure 1). The steepest increase of non-sustainable
water consumption occurred during the late 1990s and it has been associated
with changes in global temperatures where increased rates of evaporation resulted
in further demand for water (Wada & Bierkens, 2014).
Figure 1. Consumption
of blue water resources from non-sustainable resources e.g. non-renewable groundwater,
and over-abstraction of surface water levels. (Wada & Bierkens, 2014)
Not surprisingly, the increased reliance on non-sustainable resources would only cause increases in demand of water from other sources, namely groundwater. Studies (Doll et al., 2012; Wada et al., 2012) have shown that the reliance of groundwater, including non-renewable groundwater resources, are being heavily relied upon. This has been evident in areas such as India and Saudi Arabia (Wada et al., 2012). Increases in population has also been associated with increased consumption of groundwater in e.g. the US, and Mexico, however China’s population had little impact on surface and groundwater resources. Wada & Bierkens (2014) also projected the consumption of water from non-sustainable resources to increase by 40% by the end of the century.
Concluding thoughts
Globally, the consumption of freshwater has increased over
time and dangerously so has the consumption of freshwater from non-sustainable
sources. If freshwater is consumed beyond its sustainable limits, then it will
only help to exacerbate the world’s water security problems. This blog only
discusses simple linear trends of freshwater use over time, however, the
reasons to this increase in freshwater consumption, and the regional consequences
of unsustainable consumption has yet to be explored. Hence, the next few blogs
will discuss the causes for increased freshwater use and the regional
consequence of unsustainable consumption.
Why has the population growth in China had little impact on the surface and groundwater resources when in other countries it is a major factor?
ReplyDeleteThanks, that's a great question! The reason for the little impact of population growth on surface and groundwater resources is because, despite the growing population, China's irrigation practices is at its most optimal level for their current yields, and thus extra water extracted from surface and groundwater is not required in the meantime. Although, perhaps what we should be concerned about is that if China wishes to increase their agricultural yields when population size reaches a certain threshold where current agricultural practices is no longer sufficient in the near future, then more extraction from these freshwater resources is required, and this can have large impacts on surface and ground freshwater resources. I hope this answer your question! :)
Delete