5 Climate Change Impact on Hydrological Regimes …
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(Timmermann et al. 1999; Manatsa et al. 2011) resulting in more floods and droughts.
Climate change is being attributed to the intensification of the El Niño-Southern
Oscillations (e.g. McMichael et al. 2006; Collins et al. 2010; Manatsa and Behera
2013). The frequency of droughts is projected to increase and will most likely lead to
an increase in the frequency of extreme low flows and low storage episodes (Desanker
and Magadza 2001). Extreme low flows and low storage episodes inevitably affect
aquatic ecosystems, water supply, irrigation, leisure and hydro power generation.
Given that our understanding of climate change, which points towards an
increasing frequency, timing and intensity of extreme hydrological events, whose
impacts are also expected to be widespread (Easterling et al. 2000; Groisman et al.
2005; Osbahr et al. 2008; Yanda 2010; Yamba et al. 2011; Goodess 2013) as exemplified by the recent (2019) impacts of cyclones Idai and Kenneth. Knowledge about the
characteristics of extreme hydrological events is valuable for planning and designing
infrastructure. Both urban and rural areas contain many types of hydraulic engineering structures (such as dams, levees, water distribution networks, water collection networks, sewage collection networks, storm water management, etc.) which
need to be designed to accommodate peak flows of a certain magnitude in order to
function safely at a given level of risk (Schulze et al. 2014). Should the structures fail,
especially where human settlement is dense, there are potential societal, economic
and environmental consequences. Table 6 summaries the estimated costs associated
with cyclonic activity in Southern Africa.
6.3 Vulnerability to Climate Change
The combination of high climate variability and limited livelihoods options due to
high levels of poverty affecting a large proportion of the population contributes
to vulnerability to climate change. High climate variability that results in frequent
regional exposure to floods and droughts contribute significantly to the vulnerability
to current and future climate shocks to a population with limited resilience to these
shocks. Large proportions in rural and urban areas do not have access to adequate
access to water and sanitation. When extreme weather events such as floods and
drought occur, they exacerbate an existing problem. Climate change will worsen these
problems. Although efforts are being made to improve water resources management
in southern Africa, the existing systems such dams developed for satisfying domestic,
industrial and municipal uses are still not able to satisfy the demand in most parts of
southern Africa. This is due to inadequate development of infrastructure and human
capacity for managing these systems. Climate change will exacerbate these problems.
A large proportion of the southern African population has very limited livelihood
options due to poverty and limited resource base. When floods and droughts occur
they are not able to adopt options that cushion them from these shocks. If the existing
poverty levels are not eliminated, climate change will worsen these problems. Environmental degradation in the form of soil erosion, deforestation and water pollution
121
(Timmermann et al. 1999; Manatsa et al. 2011) resulting in more floods and droughts.
Climate change is being attributed to the intensification of the El Niño-Southern
Oscillations (e.g. McMichael et al. 2006; Collins et al. 2010; Manatsa and Behera
2013). The frequency of droughts is projected to increase and will most likely lead to
an increase in the frequency of extreme low flows and low storage episodes (Desanker
and Magadza 2001). Extreme low flows and low storage episodes inevitably affect
aquatic ecosystems, water supply, irrigation, leisure and hydro power generation.
Given that our understanding of climate change, which points towards an
increasing frequency, timing and intensity of extreme hydrological events, whose
impacts are also expected to be widespread (Easterling et al. 2000; Groisman et al.
2005; Osbahr et al. 2008; Yanda 2010; Yamba et al. 2011; Goodess 2013) as exemplified by the recent (2019) impacts of cyclones Idai and Kenneth. Knowledge about the
characteristics of extreme hydrological events is valuable for planning and designing
infrastructure. Both urban and rural areas contain many types of hydraulic engineering structures (such as dams, levees, water distribution networks, water collection networks, sewage collection networks, storm water management, etc.) which
need to be designed to accommodate peak flows of a certain magnitude in order to
function safely at a given level of risk (Schulze et al. 2014). Should the structures fail,
especially where human settlement is dense, there are potential societal, economic
and environmental consequences. Table 6 summaries the estimated costs associated
with cyclonic activity in Southern Africa.
6.3 Vulnerability to Climate Change
The combination of high climate variability and limited livelihoods options due to
high levels of poverty affecting a large proportion of the population contributes
to vulnerability to climate change. High climate variability that results in frequent
regional exposure to floods and droughts contribute significantly to the vulnerability
to current and future climate shocks to a population with limited resilience to these
shocks. Large proportions in rural and urban areas do not have access to adequate
access to water and sanitation. When extreme weather events such as floods and
drought occur, they exacerbate an existing problem. Climate change will worsen these
problems. Although efforts are being made to improve water resources management
in southern Africa, the existing systems such dams developed for satisfying domestic,
industrial and municipal uses are still not able to satisfy the demand in most parts of
southern Africa. This is due to inadequate development of infrastructure and human
capacity for managing these systems. Climate change will exacerbate these problems.
A large proportion of the southern African population has very limited livelihood
options due to poverty and limited resource base. When floods and droughts occur
they are not able to adopt options that cushion them from these shocks. If the existing
poverty levels are not eliminated, climate change will worsen these problems. Environmental degradation in the form of soil erosion, deforestation and water pollution