Groundwater: The Solution to Climate Change?

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.

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.

Figure 2: Aquifer productivity for Africa. The inset shows an approximate depth to groundwater (Bonsor and MacDonald 2011)
Source: MacDonald et al 2012

Additionally, a problem may arise, if there is an increase in technological advancement and there are relatively no regulations.  People, may pump too much water and overexploit groundwater resources as they become wealthier (Carter and Parker 2009).  If groundwater recharge is lower than groundwater abstraction, this will lead to groundwater level declining and decreasing groundwater availability.   Carter and Parker argue that groundwater recharge best occurs in medium intensity rainfall.  Therefore, intensification in precipitation events may not provide the aspired groundwater recharge, leading to diminishing groundwater availability.

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.