As seen in previous blogs, freshwater resources and people
will be highly affected by climate change.
As temperatures increase, there will be an increase in
evapotranspiration, leading to a high loss of surface water resources,
especially in dry areas. People in
semi-arid and arid countries in Sub-Saharan Africa are highly susceptible to
changing patterns of freshwater availability.
However, groundwater may be the solution to all climate change problems,
as it is highly available in aquifers.
This blog aims to assess groundwater as a barrier against climate change
impacts, such as droughts.
Groundwater in Sub-Saharan Africa is estimated to occupy a
volume of approximately 0.66 million
km3 of freshwater. North Africa contains a large amount of Sub-Saharan’s
groundwater storage, as Libya, Egypt, Sudan, Algeria and Chad contain the
largest aquifers of the region (MacDonald et al 2012). Furthermore, the Saharan region consists of
large areas where groundwater recharge occurred almost 5000 years ago, even
though no recharge occurs at present (MacDonald et al 2012). Hence, although
Sub-Saharan Africa is relatively dry, there are large underground resources (Figure
1). Thus, as precipitation
events will occur less frequently and intensification of extreme events such as
droughts will occur, there will be an increase of groundwater reliance. These resources could be exploited for the
provision of the domestic and agricultural water needs of people.
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| Figure 1: Groundwater storage for Sub-Saharan Africa Source: MacDonald et al 2012 |
Groundwater could be a great solution, especially since the
Millennium Development Goals (MDG), which consisted of the provision of clean
and safe water for people to alleviate diseases. This would also eliminate poverty as there
would be enough water available for food production. According to the data of 2012, 300 million
people in Africa had no access to safe drinking water and a high proportion of
the population was considered poor (MacDonald et al 2012). Hence, highlighting the
importance of groundwater as a resource of exploitation.
Problems
Nonetheless, if groundwater is exploited without adequate
sustainability measures taken, the source will slowly diminish to an extent
where people will be unable to use it.
As groundwater recharge will not occur as frequently and there will be
an increase in demand of groundwater leading to diminishing groundwater
resources (Carter and Parker 2009). As
it is expected that population will increase by more than half a billion, by 2050
this suggests that more people will need access to water resources (Taylor et al 2009). Hence, with an increase in
demand for food production and sanitary health, groundwater demand will increase
substantially, especially in urbanised areas (Taylor et al 2009). This may lead to overexploitation of
groundwater resources, questioning for how long groundwater will be available
if no substantial groundwater recharge occurs.
However, this may be highly variable, as there is not a lot of observed
data sets of groundwater resources.
Therefore, there is high uncertainty of how groundwater recharge may be
impacted by climate change impacts (Taylor et al 2009).
Another, issue may be that some of the groundwater is very
deep and thus it is hard to pump out and it is away from remote areas, hence
leading to high costs (Figure 2) (MacDonald et al 2012). There may be a barrier in the ability of
pumping groundwater from deep aquifers, as a high proportion of the population
lives in deprived conditions and do not have the economic ability to invest in
mechanical pumps of high power.
Moreover, many governments may not be able to provide large power pumps
across the whole country to distribute the water (MacDonald et al 2012). Thus unfortunately some areas will be unable
to exploit groundwater resources to the desired degree. Controversially, Taylor et al 2009 argue that
groundwater infrastructure is relatively cheap compared to surface water
infrastructure and maintenance of groundwater resources are cheaper, hence
questioning to what degree this will limit the ability of people to abstract
groundwater from deep aquifers.
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| Figure 2: Aquifer productivity for Africa. The inset shows an approximate depth to
groundwater (Bonsor and MacDonald 2011) Source: MacDonald et al 2012 |
Lastly, many aquifers may be transbourdary, meaning they are
beneath more than one country. Hence,
this creates hydropolitical issues (Taylor et al 2009). As there is an increase in groundwater
demand, due to increased climatic changes, there may be an issue of who uses
the water and who gets a substantial degree of the groundwater source. For instance increased groundwater
abstraction in one nation may not allow rivers to be regenerated due to
baseflow hence affecting a transboundary river. This may lead to many
disagreements between nations and even wars.
Conclusion
With increasing climate change impacts this increases
groundwater reliance. Groundwater use
combined with a technological advancement, is highly essential for the
prosperity of the people. However, if
groundwater is overexploited it is questionable to what degree groundwater will
be available and for how long. Although
groundwater may be a solution to climate change for a certain period of time,
this does not mean groundwater will always be available to people. Hence emphasising the importance of trying to
monitor groundwater abstraction through government regulations to mitigate
climate change impacts.
