The 2009 released paper of R.C. Carter & A. Parker "Climate change, population trends and groundwater in Africa" relates to the issues of Climate Change Impacts on water resources in Africa in correspondence with an immensely growing population and their demand for water resources.
Even though Climate Change will affect Africa as well as other countries on the globe with rising temperatures, changes in rainfall &evaporation rates and shifts in annual rainfall distribution pattern, the impact of a massive growing population with a trend toward urbanization might have an even higher and more obvious effect on renewable groundwater resources and recharge.
Changes
in rainfall pattern
Even
small changes in mean annual rainfall and its temporal and spatial distribution
can influence the entire water balance and groundwater recharge. The annual
rainfall already varies between the years, months and regions (as shown in the diagram
below). Shifts in start and end dates of rain periods, longer dry period
durations as well as an increased amounts of extreme events can affect
agriculture and groundwater tables.
Not
every rainfall is referred to as Hydrologically effective (HER). Only rainfall
that produces direct runoff (intense rainfall) and groundwater recharge
(rainfall exceeding evapotranspiration & high soil water content) is
referred to as HER, though, limited to certain time periods.
Recharge
values peak from long-term medium-intense rainfall rather than short-term
high-intensity rainfall. The biggest shifts in rainfall change is predicted for
the driest regions in Africa.
 |
| Annual rainfall 1948–2001, Niger (mm) (solid line indicates MAR for the period) |
Effects
of growing population and urbanization on groundwater
The
rising population and their shift towards urban and rural areas also leads to a
change in land use, land cover and water resources. An expanding population
itself will have a higher demand for groundwater resources but combined with an
increasing urban population their domestic, industrial and hydro-electrical
demand will rise immensely due to the change in water use patterns. Per capita
consumption will rise with their new ´live style´ as well as a shift in
agricultural water use towards large-scale irrigation unattached to rainfall
pattern in order to meet the rising need of food.
Changes
in land use from deep-rooted natural vegetation to annual short-rooted crop
will lead to a change in groundwater recharge due to changed soil capacity in
the root zone and evaporation.
 |
| A single-layer conceptual model of groundwater recharge (Eilers et al., 2007). |
Therefore it is certain that the Climate Change will effect Africa in many different ways but the growing population and their increasing demand for resources is as much of a threat as rising temperatures.
