**1. Introduction**

Developing countries are in front of unprecedented changes, which will determine their paths in economic, environmental and social terms. Climate change, demographic explosion, new international strategies and economic development opportunities constitute some of the competitive drivers of their future pathways.

The Zambezi river basin (ZRB) is the fourth largest basin of Africa with an area of 1.32 million km2 shared by eight countries (Angola, Botswana, Malawi, Mozambique, Namibia, Tanzania, Zambia and Zimbabwe) and populated by almost 40 million inhabitants. Currently, the available resource meets the water requirements in the Zambezi basin as a whole. However, possible conflicts between

<sup>1</sup> Zambia, Angola, Zimbabwe, Mozambique, Malawi, Botswana, Tanzania, Namibia.

riparian countries in the ZRB can arise due to the asymmetry between resource availability and population density in addition to the fact that the riparian countries have different river basin shares and investment potential, thus determining a different capability to access and use the available resource.

The first section of this chapter will present the storyline and the assumptions of each of the three future scenarios derived by the integration of the representative concentration pathways (RCPs) into the shared socio-economic pathways (SSPs).

The second and third sections deal with the demographic explosion of the riparian countries as a whole and specifically within the Zambezi area and its implication in future water-energy-food consumption.

The last section presents the economic plans of each riparian country in alignment with their long-term Gross Domestic Value (GDP) growth estimations and how the GDP composition projections impact the water and energy requirements of each economic sector. Lastly, a comparative summary of all scenarios is presented leading to the main conclusions of this chapter.

## **2. Development of the SSPs**

This chapter presents socio-economic scenarios comprised of two core elements: a storyline and the table of descriptors. The scenarios refer to a qualitative narrative describing a potential future in combination with quantitative socio-economic elements and trends. The research adopts the SSPs developed by Kriegler [1]. All of them consider mitigation and adaptation policies regarding climate change in the context of different scenarios, and each scenario is depicted by a storyline of a different future, as explained further below. In order to capture the climate change impacts in the SSPs, RCP 4.5 is selected and integrated in the scenarios of interest (**Table 1**). The main assumption of RCP 4.5 is that the carbon dioxide concentration will reach 650 CO2 eq.; the radiative forcing is stabilised at approximately 4.5 W/m2 and both will be stabilised after [2].

As presented by [3], all pathways are followed by a number of assumptions enhancing their storyline. In brief, the SSP1 depicts the sustainability scenario, where the technological change is rapid with the development goals being achieved while a path of sustainability that moves towards a less intensive use of resources is followed including lower carbon energy sources and high productivity of land. On the other side, SSP5 represents a fossil-fuelled economy, where in the absence of climate policies, energy demand is high and most of this demand is met with carbon-based fuels. Investments in alternative energy technologies are low, and there are few readily available options for mitigation. However, economic development is relatively rapid and itself is driven by high investments in human capital. Improved human capital also produces a more equitable distribution of resources, stronger institutions, and slower population growth, leading to a less vulnerable world better able to adapt to climate impacts.

The SSP2 or the business-as-usual pathway follows a consistency with the experience of the last century pattern of action. In particular, it illustrates a world, where social, economic and technological trends do not shift remarkably from historical patterns. Socio-economic progress and per capita income growth proceeds unevenly, with some countries developing rapidly while others fall short of expectations. Although sustainable development goals are a priority for global and national institutions, slow progress is made in achieving them. Environmental systems degrade, although there are some advancements, and overall, the intensity of resource and energy use declines. Global population growth is moderate increasing steadily across the twenty-first century. Income inequality persists or improves only

**35**

changes remain.

ing sections.

*Integrating Water-Food-Energy Nexus with Climate Services: Modelling and Assessment…*

**Factor SSP1 SSP2 SSP5** Population growth Low Medium Low Urbanisation High Medium High Education level High Medium High Equity High Medium High Economic growth High Medium, uneven High

development

Globalisation Connected Semi-open globalised Strongly globalised

Low Continued

Institutions Effective Modest effective Effective Technology development Rapid Medium, uneven Rapid Energy sources Renewables Fossil fuels Fossil fuels Energy intensity Low Uneven High

Natural capital (policy focus) Very high Medium/low Medium

Social capital High Medium Very high Human capital Medium/high Medium Very high

Weak focus on sustainability

degradation

Low Medium High

Low Medium Low

High Medium High

Medium/high Medium Very high

Free markets, human capital

Highly engineered

slowly and challenges to diminishing vulnerability to societal and environmental

In this chapter, the SSP2 is explicitly presented through a number of socioeconomic indexes projected and analysed, while SSP1 and SSP5 will be discussed qualitatively at the end of each section in comparison with the baseline, i.e. the SSP2. To stay as close as possible to the storyline of the SSPs, the main trends and assumptions have been downscaled for each scenario in **Table 1**. For example, population growth in SSP2 is assumed to be moderated, while in the other two scenarios, it is assumed that the growth rate will be lower, indicating a gentler slope. More details regarding the downscaling of the SSPs are provided within the follow-

The ZRB is shared by eight riparian countries, each with a different area within

ZRB. The biggest part is occupied by Zambia followed by Angola, Zimbabwe and Mozambique (see **Figure 1**). In this section, an estimation of the population within ZRB is demonstrated as developed in [5], considering social factors such as

**3. Demographic projections within ZRB boundaries**

*DOI: http://dx.doi.org/10.5772/intechopen.90914*

Policy focus Sustainable

Environmental impacts (policy focus)

Challenge to mitigation (policy focus)

Challenge to adaptation (policy focus)

Manufactured capital

Financial capital (industry/

*Summary of the main trends in important factors in the SSP.*

(industry)

GDP)

**Table 1.**

*Integrating Water-Food-Energy Nexus with Climate Services: Modelling and Assessment… DOI: http://dx.doi.org/10.5772/intechopen.90914*


#### **Table 1.**

*Sustainability Concept in Developing Countries*

in future water-energy-food consumption.

leading to the main conclusions of this chapter.

forcing is stabilised at approximately 4.5 W/m2

world better able to adapt to climate impacts.

**2. Development of the SSPs**

(SSPs).

ferent capability to access and use the available resource.

riparian countries in the ZRB can arise due to the asymmetry between resource availability and population density in addition to the fact that the riparian countries have different river basin shares and investment potential, thus determining a dif-

The first section of this chapter will present the storyline and the assumptions of each of the three future scenarios derived by the integration of the representative concentration pathways (RCPs) into the shared socio-economic pathways

The second and third sections deal with the demographic explosion of the riparian countries as a whole and specifically within the Zambezi area and its implication

The last section presents the economic plans of each riparian country in alignment with their long-term Gross Domestic Value (GDP) growth estimations and how the GDP composition projections impact the water and energy requirements of each economic sector. Lastly, a comparative summary of all scenarios is presented

This chapter presents socio-economic scenarios comprised of two core elements: a storyline and the table of descriptors. The scenarios refer to a qualitative narrative describing a potential future in combination with quantitative socio-economic elements and trends. The research adopts the SSPs developed by Kriegler [1]. All of them consider mitigation and adaptation policies regarding climate change in the context of different scenarios, and each scenario is depicted by a storyline of a different future, as explained further below. In order to capture the climate change impacts in the SSPs, RCP 4.5 is selected and integrated in the scenarios of interest (**Table 1**). The main assumption of RCP 4.5 is that the carbon dioxide concentration will reach 650 CO2 eq.; the radiative

As presented by [3], all pathways are followed by a number of assumptions enhancing their storyline. In brief, the SSP1 depicts the sustainability scenario, where the technological change is rapid with the development goals being achieved while a path of sustainability that moves towards a less intensive use of resources is followed including lower carbon energy sources and high productivity of land. On the other side, SSP5 represents a fossil-fuelled economy, where in the absence of climate policies, energy demand is high and most of this demand is met with carbon-based fuels. Investments in alternative energy technologies are low, and there are few readily available options for mitigation. However, economic development is relatively rapid and itself is driven by high investments in human capital. Improved human capital also produces a more equitable distribution of resources, stronger institutions, and slower population growth, leading to a less vulnerable

The SSP2 or the business-as-usual pathway follows a consistency with the experience of the last century pattern of action. In particular, it illustrates a world, where social, economic and technological trends do not shift remarkably from historical patterns. Socio-economic progress and per capita income growth proceeds unevenly, with some countries developing rapidly while others fall short of expectations. Although sustainable development goals are a priority for global and national institutions, slow progress is made in achieving them. Environmental systems degrade, although there are some advancements, and overall, the intensity of resource and energy use declines. Global population growth is moderate increasing steadily across the twenty-first century. Income inequality persists or improves only

and both will be stabilised after [2].

**34**

*Summary of the main trends in important factors in the SSP.*

slowly and challenges to diminishing vulnerability to societal and environmental changes remain.

In this chapter, the SSP2 is explicitly presented through a number of socioeconomic indexes projected and analysed, while SSP1 and SSP5 will be discussed qualitatively at the end of each section in comparison with the baseline, i.e. the SSP2. To stay as close as possible to the storyline of the SSPs, the main trends and assumptions have been downscaled for each scenario in **Table 1**. For example, population growth in SSP2 is assumed to be moderated, while in the other two scenarios, it is assumed that the growth rate will be lower, indicating a gentler slope. More details regarding the downscaling of the SSPs are provided within the following sections.

#### **3. Demographic projections within ZRB boundaries**

The ZRB is shared by eight riparian countries, each with a different area within ZRB. The biggest part is occupied by Zambia followed by Angola, Zimbabwe and Mozambique (see **Figure 1**). In this section, an estimation of the population within ZRB is demonstrated as developed in [5], considering social factors such as

**Figure 1.** *Zambezi river basin (source: [4]).*

mortality, fertility, international migration and urbanisation for the period from 2018 to 2060. The analysis below is based on the SSP2 scenario, which illustrates the middle of the road scenario, assuming that population fertility and the urbanisation level are both medium levels. SSP1 and SSP5 are examined as a comparison to the SSP2 at the end of the section.

#### **3.1 Population growth per country**

Population growth by country is estimated and presented in **Figure 2**. In order to calculate those trends, a simple model with one lag considering the values of the previous year and the annual population growth rates per country is run. A comprehensive and transparent selection of the growth rates was an important stage of this exercise, due to its impact on the future trends. After comparing a number of resources, population growth rates provided by [6] seem to have the most transparent and analytical approach. A crucial benefit of this report is not only the 100-year

**37**

**Figure 3.**

*Population growth by major urban centre.*

*Integrating Water-Food-Energy Nexus with Climate Services: Modelling and Assessment…*

forward looking but also the time slice of the predictions to 5-year periods, which enables projections to be comparatively more accurate. In order to be in alignment with SSP2 pathway, a population growth rate with constant mortality, normal international migration and median fertility assumptions is selected among the 10

In Tanzania, population is proceeding apace in the next 40 years and it is expected to more than double, reaching almost 150 million people, which is of exceptional importance. However, such an enormous population increase would be accompanied by high concentration in major urban cities. Although only one urban city of Tanzania (as urban centres are considered cities with a population greater than 100,000 inhabitants), Katumba, located at the borders of Malawi, is identified within ZRB area, intra-urban agglomeration effects may be noticed increasing so the intensions over the water use of the river. Moreover, Malawi and Zambia, which together have as many inhabitants within ZRB as the rest of the countries jointly, seem to follow similar growth trends starting from 20 million to 18.6 million correspondingly and exceeding 43 million people each by 2060. Hence, the increased needs for water from half of the ZRB population are increasing, but not rapidly in the following 30 years enabling so, factors such as innovation and precautions to

Major urban centres are outlined by large populations, intensive economic activity and infrastructural development, which inevitably impose a significant strain on natural resources and especially water. Out of the 56 major urban centres with population greater than 100,000 identified for all riparian countries, 19 are geographically located within the boundaries of the ZRB. This chapter presents the population increase of these 19 major cities and the transition of smaller cities into

The estimation of the demographic development for each riparian city is based on the data derived by [7] regarding their population levels in 2018 and by annual population and urbanisation growth rates provided by [6, 8]. **Figure 3** illustrates the population projections by major cities within ZRB, with Lusaka (Zambia) and Harare (Zimbabwe) reaching 3.2 million and 2.6 million people by 2060. The most

major urban centres within ZRB boundaries during the period of interest.

*DOI: http://dx.doi.org/10.5772/intechopen.90914*

indices provided in [6].

play a considerable role.

**3.2 Population growth per major urban centre**

**Figure 2.** *Population growth by country.*

*Integrating Water-Food-Energy Nexus with Climate Services: Modelling and Assessment… DOI: http://dx.doi.org/10.5772/intechopen.90914*

forward looking but also the time slice of the predictions to 5-year periods, which enables projections to be comparatively more accurate. In order to be in alignment with SSP2 pathway, a population growth rate with constant mortality, normal international migration and median fertility assumptions is selected among the 10 indices provided in [6].

In Tanzania, population is proceeding apace in the next 40 years and it is expected to more than double, reaching almost 150 million people, which is of exceptional importance. However, such an enormous population increase would be accompanied by high concentration in major urban cities. Although only one urban city of Tanzania (as urban centres are considered cities with a population greater than 100,000 inhabitants), Katumba, located at the borders of Malawi, is identified within ZRB area, intra-urban agglomeration effects may be noticed increasing so the intensions over the water use of the river. Moreover, Malawi and Zambia, which together have as many inhabitants within ZRB as the rest of the countries jointly, seem to follow similar growth trends starting from 20 million to 18.6 million correspondingly and exceeding 43 million people each by 2060. Hence, the increased needs for water from half of the ZRB population are increasing, but not rapidly in the following 30 years enabling so, factors such as innovation and precautions to play a considerable role.

#### **3.2 Population growth per major urban centre**

Major urban centres are outlined by large populations, intensive economic activity and infrastructural development, which inevitably impose a significant strain on natural resources and especially water. Out of the 56 major urban centres with population greater than 100,000 identified for all riparian countries, 19 are geographically located within the boundaries of the ZRB. This chapter presents the population increase of these 19 major cities and the transition of smaller cities into major urban centres within ZRB boundaries during the period of interest.

The estimation of the demographic development for each riparian city is based on the data derived by [7] regarding their population levels in 2018 and by annual population and urbanisation growth rates provided by [6, 8]. **Figure 3** illustrates the population projections by major cities within ZRB, with Lusaka (Zambia) and Harare (Zimbabwe) reaching 3.2 million and 2.6 million people by 2060. The most

**Figure 3.** *Population growth by major urban centre.*

*Sustainability Concept in Developing Countries*

SSP2 at the end of the section.

*Zambezi river basin (source: [4]).*

**Figure 1.**

**3.1 Population growth per country**

mortality, fertility, international migration and urbanisation for the period from 2018 to 2060. The analysis below is based on the SSP2 scenario, which illustrates the middle of the road scenario, assuming that population fertility and the urbanisation level are both medium levels. SSP1 and SSP5 are examined as a comparison to the

Population growth by country is estimated and presented in **Figure 2**. In order to calculate those trends, a simple model with one lag considering the values of the previous year and the annual population growth rates per country is run. A comprehensive and transparent selection of the growth rates was an important stage of this exercise, due to its impact on the future trends. After comparing a number of resources, population growth rates provided by [6] seem to have the most transparent and analytical approach. A crucial benefit of this report is not only the 100-year

**36**

**Figure 2.**

*Population growth by country.*

populated riparian cities are located in Zambia, Zimbabwe and Malawi, with cities located in Mozambique and Tanzania following less vigorous growth. However, 12 non-major urban areas today will become significantly inhabited in the next 40 years attracting investments and necessary infrastructure in order to host the rising population. This transition will also be accompanied by additional pressure on water-energy-food supplies, the demand of which in urban areas tends to be significantly higher. Angola, Botswana and Namibia are not represented in the graph, since none of their major or potentially major cities is placed within ZRB area.
