IMPACT OF CLIMATE CHANGE AND MONITORING ANALYSIS ON WATER RESOURCES IN SOUTHERN AFRICAN DEVELOPMENT...

IMPACT OF CLIMATE CHANGE AND

MONITORING ANALYSIS ON WATER RESOURCES

IN SOUTHERN AFRICAN DEVELOPMENT

COMMUNITY COUNTRIES (SADC): Critical review

Authors: JK Bwapwa, AT Jaiyeola

Mangosuthu University of Technology

Faculty of Engineering

Durban, Umlazi

South Africa

Paper submitted for presentation at the world weather open conference 2014, Montreal Canada

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ABSTRACT

The effects of global warming are starting to manifest themselves with increasing global surface

temperature and more voluminous rainfall being dumped in some parts of the world that have not

experienced them before. Climate change is wreaking havoc, but its impact is greater in some

parts than in others: arid and semi-arid regions become drier and hotter while cold regions often

become colder. Extreme weather is being felt everywhere, but the impact of climate change is

greater in countries where poverty and diseases remain prevalent. This is the case in the African

continent, particularly in the Southern African Development Community, where most of its

populations are engaged in agriculture that is sustained by water-fed rainfall. Although this

region has some of the longest and biggest river basins in the world, water scarcity, especially

safe water, is not unheard of. Climate change, therefore, poses a greater danger to this region

than any other. Many simulation models for climate change indicate that the region will be

subjected to increased temperature by the end of the century that will in turn impact hydrological

cycles that will potentially increase the risk of groundwater drought and decrease runoffs of its

river basins, upon which millions of people are dependent for their livelihood and sustenance. In

addition, the quality of the water, surface or ground, are expected to alter as a consequence of

decreased rainfall or scarcity of water. This will affect many in the region where only one state

has attained a 100 per cent access to safe water and the rest are still struggling to find means to

deliver safe water to their inhabitants. This scenario will undoubtedly make things almost beyond

bearable for the SADC countries. It is therefore, imperative that the policymakers of the region

act now to impose measures to mitigate the impact of climate change as well as prepare the

region to be adapted and resilient to its effects.

Keywords: : climate change, water scarcity, water resources, rainfall

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INTRODUCTION

Although there are sectors that persistently deny the advent of global warming primarily as a

result of anthropogenic activities, the consensus in the scientific world is that it does exist and

the resultant climate change is presently beginning to wreak havoc on the earth and its people.

With climate change, extreme conditions are looming; wet season becomes wetter and dry

season becomes even drier. The change in climate is, however, variable and dependent on the

region. Various simulation models for climate change have shown very negative prospects for

the continent of Africa, which is predicted to grow hotter even as present figures show that its

temperature has been increasing since the beginning of the last century. For this largely

impoverished continent, this is problematic largely because water resources is already considered

scarce as it is and most of the population is mostly dependent on agriculture that is chiefly rain-

fed. This is particularly true with the Southern African Development Community, a group of 14

countries located in the southernmost tip of the African continent where poverty remains the

greatest challenge to this day. If the prediction of these studies become true and many are

beginning to be felt across the region, it will worsen the incidences of diseases to which most of

the population are at risk to such as cholera and malaria because of the impact on water scarcity

to the quality of the water sources. Studies have also shown that quantity and quality of water

particularly in Africa has a connection as many diseases are vulnerable to water scarcity and

flooding. Anticipating the impact of the climate change in the region’s water resources is,

therefore, important so that the region can prepare and initiate mitigating solutions to the

problems that are expected to arise as a result of climate change’s impact.

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LITERATURE REVIEW

Many scientists concur that indeed global warming is happening on the basis of many

manifestations, among which is rising globe surface temperature. It is estimated that such

temperature has risen by about 0.74C° from 1906 to 2005 with the rapid increase occurring most

in last 50 years. In addition, increasing temperature can also be observed in global average air

and ocean systems and other phenomena as rising water level and widespread melting of snow

and ice. The hastening of global warming beginning sometime in the 20th

century was attributed

to greenhouse gases emission. A report released by the Intergovernmental Panel on Climate

Change indicated that global warming significantly impacts hydrological systems and cycles and

these are discernible in “changing precipitation patterns, intensity and extremes; widespread

melting of snow and ice; increasing atmospheric vapor; increasing evaporation; and changes in

soil moisture and runoff” (Manase, 2009).

Like most of Africa, water is a primary concern in the Southern Africa Development Community

(SADC hereafter). Composed of the countries of Angola, Botswana, DR Congo, Lesotho,

Madagascar, Malawi, Mauritius, Mozambique, Namibia, Seychelles, South Africa, Swaziland,

Tanzania, Zambia and Zimbabwe (SADC: Member States 2013), the SADC has “unevenly

distributed water resources compared to population and settlement patterns coupled with a

variable and changing patterns” (SADC: Natural Resources 2012). About 70% of the population

in this region is dependent on agriculture, which in turn is being supported mainly by rain water,

which thus implies the region’s close link with climate. With climate change, extreme weather

conditions are expected and many climate change models reveal a likelihood of severe droughts

and floods. This does not bode well for SADC countries, which is a dry region with only a mean

annual rainfall that is only half of the world’s average (Colvin et al 2009). In addition, the region

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is known to have experienced critical low levels of water in lake storage and major dams during

droughts. Studies have indicated that the most significant impact of global warming in the SADC

region will likely be reduction in soil moisture and in runoff, which in turn will affect the

region’s economy, particularly in countries whose reservoir storage are vulnerable to changes in

runoffs and droughts (Manase, 2009). The predicted intense droughts as a consequence to

climate change in SADC will bring about water scarcity to the region. As of present, the SADC

countries have different rates of access to improved drinking water sources. The figures vary

from a high of 100% in Mauritius to a low of 42% in Mozambique (Tucker 2010). Water

scarcity, which is predicted to result from climate change can diminish the quality of water

because of higher concentration of salt and chemical contaminants as well as bring about higher

risks for water-borne diseases, such as cholera, and vector-borne diseases, such as malaria

(McMichael 2009).

A. GROUNDWATER RESOURCES

The geologic structure and the climate in the SADC largely affect its groundwater resources.

Studies have shown that more than half of the region is covered with crystalline rocks with

aquifer systems that hamper the free extraction of underground water. Only a few aquifer

systems in the region exist that can are a major supply of groundwater because of the high

salinity in the region (Mukheibir 2005). In addition, its semi-arid and arid climates allow only a

low recharge rate of groundwater and thus, in this region water is a valuable commodity. This is

especially true in the countries of Angola, Botswana, Namibia, western South Africa and western

Zimbabwe. In the eastern and northern parts of the region, which are characteristically tropical

and humid, groundwater resources are comparatively abundant. Domestic water supplies are

sourced primarily from groundwater resources in the region. Botswana, Namibia, and Zimbabwe

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are the SADC countries chiefly relying on groundwater resources while DR Congo, Lesotho and

Seychelles are the least dependent on these sources (Braune and Xu 2008). In general, around

70% of the people in region depend on groundwater as their only source of water (IGRAC 2013).

Various climate change simulations and modeling in the SADC region have indicated hotter

climate, less rainfall and severe droughts. Prolonged droughts significantly groundwater supply

and jeopardizes the health and well-being of those dependent on it with those living in the rural

areas viewed as the most likely to bear the most harm because of their “unilateral and life-

depending reliance on groundwater and groundwater- fed systems for all uses” (Villholth et al

2013, p. 1). Climate change is thus, expected to bring groundwater drought (GWD thereafter) to

the SADC region. GWD is initiated by absence of rainfall, which brings about a series of phases

ultimately culminating in GWD: diminished water recharge; lessened groundwater storage, and;

decreased discharge. The impact becomes progressive as bigger and larger aquifers become

affected by the deceasing water storage until a full-blown GWD emerges. The most critical

symptom of GWD is the decrease of phreatic groundwater levels (Villholth et al 2013). The

phreatic level refers to the groundwater surface in the soil layers that is unconfined and is near

the surface primarily in the topographic depressions where evaporation is enhanced (Kafri and

Yecheill 2010). This depletion in the phreatic level creates an obstacle to access to groundwater

even in shallow wells and springs. In a study conducted by Villholth et al (2013) integrating the

potential aggravating factor of climate, the GWD risk of the SADC was mapped and assessed.

Climate change presented a significantly negative impact on such risk placing a potential 39

million people in jeopardy as a result. Figure 1 shows that relative risks of each and every

country within SADC with Namibia,

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Figure 1 : GWD Comparative Risk in SADC

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Botswana and parts of Zimbabwe and South Africa, mostly lying in the arid zones, likely to

sustain high to very high risks of GWD while the DR of Congo and the outlying states near the

outermost borders adjacent to the bodies of waters least likely to be susceptible to GWD.

Botswana, Namibia and South Africa have large multi-layered unconfined aquifers lying above

confined aquifers.

OVERVIEW AND ANALYSIS ON SELECTED SURFACE WATER

RESOURCES

Any changes in the local rivers, particularly from overland flow, will significantly affect many

people in the SADC. The region has about 12 major river basins identified by de Witt and

Stankiewicz (2006). A decrease in precipitation, which is one of the consequences of climate

change, will have the greatest impact on the unstable region and the researchers predicted that a

decrease in perennial drainage will affect 25% of the entire Africa by the end of the present

century (de Witt and Stankiewitz 2006). There are 15 major river basins in the region, which

provide water supply to its members. The following discussion will center on some of the

biggest basins of SADC, which affects the largest groups of people.

1. The Okavango River Basin: Angola, Namibia and Botswana

The Okavango River Basin - ‘one of the least developed basins in Africa’ and also touted to be

‘one of the last pristine river systems in Africa’ (cited in Andersson 2006, p. 3) – is a water

system shared by three SADC countries, namely: Angola, Namibia and Botswana. It covers a

hydrologically active area of 323,192 km2 that begins in the central Angola and is known as the

Kubango rising at an elevation of 170 meters in Angola’s highland plateau. The Culto-Cubangco

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province in Angola generates the most stream flow of the River, thereafter flowing in the

margins of Namibia and Angola before finally settling in the Okavango Delta in Botswana.

There are about 600,000 people who are dependent on the Okavango River system with three

major urban centers consisting of Menongue in Angola, Rundu in Namibia and Maun in

Botswana (OKACOM 2014). Murray-Hudson et al (2006) used a mathematical model to assess

the potential result that climate change will bring to the delta. They concluded that a significant

drying of the Delta may ensue with a combined climate change and human abstraction. The

drying up of the Delta in turn will result in changes in its ecosystem such as decreasing space for

swamp, vegetation and grassland.

2. Zambezi River: Angola, Botswana, Malawi, Mozambique, Namibia,

Tanzania, Zambia, Zimbabwe

The Zambezi River is the fourth largest river in Africa flowing 2,574 kilometers from its source

in Zambia through Angola and along the borders of Namibia, Botswana and Zimbabwe and other

SADC countries finally filtering into Mozambique and into the Indian Ocean. About 32 million

people rely on the river primarily for agriculture and also fishing. It is also a source of drinking

water, transportation route, hydroelectric power and tourism. A drought in the river could mean

outbreaks of water-borne and vector-borne diseases (Zambezi River Initiative 2010). In 2001, the

IPCC predicted the River to bear the most impact of climate change among 11 major African

river basins (Beilfuss 2012). As a consequence of climate change, the temperature in the

Zambezi River is expected to increase every ten years by as much as 0.03° to 0.06° C. This will

mean a corresponding increase in rates of evaporation and transpiration to a system already

suffering a 1,360 mm evapotranspiration because of its semi-arid condition with potential

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evaporation going above rainfall. A 10%-25% increase in rates of evaporation and transpiration

for the next 100 years is expected for this River as a result of climate change (Beilfuss 2012).

Climate change is also predicted to decrease rainfall in the Zambezi River Basin in the next

years. This means more intense droughts in the countries of Botswana and Zambia where the

River runs as well as drier weather in Zambia and Malawi and less precipitation in Mozambique

and Zimbabwe (Beilfuss 2012). A decrease in rainfall and increase in evapotranspiration

necessarily results, as far as the Zambezi River is concerned, with decreased runoff and a

significant reduction in streamflow, by as much as 26%-40%, according to the IPCC. Overall,

this implies a decrease in surface water supply in a region classified as an unstable rainfall region

(Beilfuss 2012). The impact of this on SADC countries that are dependent on it for water supply

is grave. Malawi, for example, has a labor population mostly in the agricultural sector, i.e. 85%.

Its agricultural sector is a prominent part of its economy contributing 35% to its GDP and 83%

of its foreign-exchange while supporting 80% of its population, most of which live in the rural

areas (Economic Commission for Africa 2012). On the other hand, Namibia, Botswana and

Zimbabwe are prone to droughts and therefore, may be more sensitive to climate change that the

more humid areas of Zambia and Tanzania (Leichenko and O’Brien 2001)

3. Limpopo River Basin: Botswana, Mozambique, SA, Zimbabwe

The Limpopo River Basin is shared by the SADC countries of Botswana, Mozambique, South

Africa and Zimbabwe spread out for a total area of 416,296 square kilometers, but 45% of it is

found in South Africa. The entire Basin involves a population of about 14 million people, living

in both rural and urban conditions. It has an uneven climate that is tropical rainy in some parts,

i.e. Mozambique’s coastal plain, tropical dry savannah and tropical dry desert, i.e. inland

Zimbabwe. Similarly, rainfall is uneven from place to place, with low rainfall characterizing the

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hot, dry areas of the west and center side and high rainfall in the eastern part, and from year to

year. A hydrological model simulating climate change conditions revealed that the highest

rainfall decrease is likely to occur in Botswana and the least is South Africa. Overall, there were

significant reductions in annual rainfall and water availability for all riparian countries and for all

climate change scenarios employed by the authors (Zhu 2010). These results can have a greater

impact on those who are primarily engaged in agriculture than those who are not and those who

have less access to safe and quality water. In this case, South Africa and Mauritius, which has

only less than 20 per cent of its people engaged in agriculture as opposed to the 80% in

Tanzania, Mozambique and Malawi, will not bear the same impact as the latter (Economic

Commission for Africa 2012). However, as earlier cited Mauritius has the lowest rate of access

to quality care and decreased rainfall and severe droughts in its area are likely to make this rate

even lower.

ANALYSIS AND DISCUSSIONS

The various studies and the simulation modeling used to predict the impact of climate change on

the water supply, both surface and ground, of the SADC showed a very dim prognosis of the

future of these countries. This is compounded by the fact that poverty and a number of diseases

continue to be the challenges that these countries are facing in the 21st century. As can be seen

from figures, many of these countries do not have 100 per cent access to safe and quality water

and are dependent on rain-fed water for agriculture, the sector upon which majority of their

population belong. The population will even be more at risk for diseases because of water

scarcity as well as the declining safety of the water quality, which is expected to be more salty

and more toxic because of contaminants. The most vulnerable areas to climate change are those

that are located in the semi-arid and arid zones because of the risk of groundwater drought and

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decreased river runoffs that will be precipitated by diminished rainfall. Botswana, Namibia and

Zimbabwe are particularly at risk for GWD while Botswana and Zambia most susceptible to

decreased river runoffs. There is therefore, so much that is at stake when the impact of climate

change makes itself manifest in full force on the countries of the SADC.

CONCLUSIONS AND RECOMMENDATIONS

As can be gleaned from the preceding discussion, the SADC countries will be significantly

impacted by climate change because of expected decline in rainfall that can significantly impact

on the recharge, storage and discharge of groundwater resources and river runoffs, especially in

the downstream of the river basins. Considering that the regions is still in the process of

combating poverty and eradicating diseases that afflict many in the poorer sectors of society,

such a scenario will undoubtedly exacerbate the region’s condition. It is therefore, imperative

that the region acts now to bring about mitigating measures to anticipate the predicted scenario

that will ensue because of climate change. One of these mitigating measures is to integrate into

poverty reductions plans of the region climate change impact so that the projects being put in

place are all geared not only to maximize economic aspects, but also anticipate changes brought

about by climate change. In the Zambezi region, for example, where hydropower structures are

being built, integrating climate change scenarios should guide the policymakers to adopt design

that will abate rather than aggravate the effects of climate change. Aside from mitigation

measures, the SADC policymakers should also plan for measures that will help the region adapt

to the kind of changes that will be brought about by climate change to make the region resilient

to whatever changes the future holds.

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IMPACT OF CLIMATE CHANGE AND MONITORING ANALYSIS ON WATER RESOURCES IN SOUTHERN AFRICAN DEVELOPMENT...

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