Adapting to Climate Change: Urban Cities

Adapting to climate change is not only important in agricultural practices, but it is also important for urban cities to adapt as well. In this blog, I want to briefly introduce the different ways in which adaptive measures to climate change are adopted by comparing two case studies of two cities.

The first case study is Kampala city, this is the largest city in Uganda and it is expected to experience greater incidences of flooding as a result of climate change; flood-related problems such as pollution of water supplies, health risks and the spread of diseases are more likely to occur (Lwasa, 2010). Lwasa (2010) stresses the importance of identifying the impacts of climate change on urban populations, and subsequently determining the vulnerability of the urban population before attempting to apply adaptive measures. For example, in 2007, there were eight flood events and urban poor settlements such as Natete and Katwe were most vulnerable to these floods. This is because these settlements were informal and lacked the necessary infrastructure to withstand such floods. Hence, improving urban infrastructure, and addressing runoff and floods through building dams or planning crop cover to reduce storm flow are some adaptive measures that can be adopted. Other secondary impacts of the floods must not be ignored; worsening health conditions, economic damages and disrupted transport networks, and the overall lowering of the water table of Lake Victoria, can equally worsen livelihoods in many communities. Communities are willing to adapt but lack the means to do so, hence local and national governments must also be willing to take part in helping communities to adapt to climate change impacts. The Kampala City Council has an important role in governing the funds and allocation of resources, and the decision-making processes to adapting to climate change but cooperation with the community and their knowledge is also required to effectively increase the resilience of many communities to climate change impacts. Lwasa (2010) stresses the importance of understanding the context of urban cities and communities before choosing suitable adaptation strategies.

The second case study is Cape Town, South Africa, whereby water quantity, access and quality are the main problems that will occur because of climate change. Cape Town relies on surface and groundwater resources in the local area, however climate change scenarios such as an increase in average temperature by 1C by 2050 in Western Cape, or a general drying in most seasons in the south-eastern region of Western Cape can make these resources highly vulnerable (Ziervogal et al., 2010). Ziervogel et al. (2010) case study in Cape Town explains that while lower rainfall yields are a problem, the increasing demand for water due to population increases, poor wastewater management and underinvestment in infrastructure remains the largest problems and threats to water security in the city. To address these issues, climate change scenarios are incorporated into water management policies and planning, however, actors (communities, local governments, and national government actors) at all levels will need to agree that climate change adaptation is required and how it should be implemented. A combination of both supply and demand-side policies should be used; supply-side policies include building larger dams, improve water treatment processes, and exploiting other water resources, and demand-side policies include limiting water consumption and distribution. Ziervogel et al. (2010) noted that supply-side policies raised the cost of water and thus was too expensive for locals, and demand-side policies were more favourable and effective such that after the restrictions was imposed the demand for water reduced.

Adapting to climate change requires an understanding of the socio-economic background, and more specifically how climate change will have an impact on the urban city. The Kamapla case study saw the direct impacts of climate change on the city through floods and health-related impacts, which acted as a stronger incentive for adaptive measures. The Cape Town case study, however, experienced threats to their water supply through higher temperature and evapotranspiration rates, so it was more difficult to experience the impacts of climate change in the immediate term and this led to discussions about the priority of addressing and adapting to the impacts of climate change. This blog very briefly introduced how urban cities adapt to climate change through two examples but adaptation is much more complex than what was explained here, but I wanted to highlight the different factors and incentives that may govern the way an urban city would react to climate change. 

Adapting to Climate Change: Small-Scale Farmers

In my previous blog, I explored the impacts of climate change on agricultural farmers through the changes of rainfall and temperature across Africa. In the recent COP22 negotiations in Marrakech, agricultural adaptation to climate change was put at the forefront by 28 countries; Ban-Ki Moon explains that “Adaptation is not a luxury. It is a cautious investment in our future” (AAA, 2016a). A positive product of these negotiations saw the development of an initiative called the ‘Adaptation of African Agriculture (AAA) Initiative’ where the importance of climate change impacts on African agriculture is raised. This initiative focuses on implementing specific projects to improve Africa’s agriculture on all levels, ranging from soil management, agricultural water control, risk management and capacity building (AAA, 2016b). Perhaps, this negotiation can prove to be a pivotal point in elevating the concerns regarding agriculture and water availability. In this blog I want to explore the ways in which these farmers adapt to climate change, specifically exploring the small-scale farming techniques and adaptive measures to changing rainfall patterns and water availability for irrigation.

Rainwater Harvesting – Soil Moisture Conservation

This clip below provides a brief insight into the impacts of climate change and a farmers’ response to short rainfall, intense heat and the drying of soils through rainwater harvesting. 

Agriculture in many countries across Africa is highly dependent on rainwater and so climate change threatens a significant number of people’s livelihoods (Yosef & Asmamaw, 2015). Rainwater harvesting through storage in the soil profile is a form of in-situ water conservation whereby rainwater is held in the place that it falls. The amount of water stored in the soil is limited by the soil holding capacity and rate of infiltration, and in arid and semi-arid areas where coarse soils and high hydraulic conductivity, the amount of water stored in the soil is extremely limited and thus may not be a useful adaptive method (Yosef & Asmamaw, 2015). However, soil practices can be used to change the condition of the soil and thus improve the soil moisture retention. For example, in the drought affected areas of Ethiopia, stone bunds of 30cm wide and a height of 0.74m stone bunds are used to reduce runoff and soil erosion, and to increase soil moisture (Biazin et al., 2012). Other techniques such as terraces and trenches are also effective in increasing soil moisture and was widely adopted in traditional agricultural practices in many African countries. In Burkina Faso, the depth of soil pits was deepened and compost/manure was applied, this changed the composition of the soils, thus enabling the conservation of more water in the soil (Baizan et al., 2012). A study by Birru et al. (2012) found that farm yard manure and mulching significantly enhanced soil moisture retention. Soil moisture storage with mulch treatments of 6 ton ha^-1 of mulch retained 216.11mm of water, 39.15mm more water than soil without mulch treatment. 4 ton ha^-1 of straw mulch treatment retained 215.40mm of water, which is similar to the mulch treatment, thus showing that the straw mulch treatment has higher soil water retention capacities greater than mulch treatment.

Rainwater Harvesting – Macro-catchment

Larger rainwater harvesting techniques consists of collecting rainwater or runoff and diverting this water to a storage structure and target area through a macro-catchment system (Biazin et al., 2012). A study by Lebel et al. (2015) explains that rainwater harvesting techniques can prove to be a ‘valuable adaption strategy to climate change’, more specifically for maize crops because these techniques can address large issues concerning water deficits in the future. The study predicts that under RCP8.5 climate scenarios (highest greenhouse gas emissions during 2050s), maize yields have the potential to increase by 14-50% due to rainwater harvesting techniques meeting the demands required for productivity in Africa. Although, this study notes that in semi-arid and arid regions, rainwater harvesting techniques are unlikely to mitigate the impacts of intense temperatures and lack of rainfall, so other adaptive techniques are required.
An interesting study by Recha et al. (2015) suggested that the adoption of these rainwater harvesting techniques depended on the number of livelihood options available to small-scale farmers in Tharaka, Kenya. Farmers who depended on crops for their livelihoods was more likely to use rainwater harvesting techniques, but other attributes such as the cropland size during the MAM rainfall season, or the number of children per household also influenced the adoption of rainwater harvesting techniques. This shows that certain conditions would influence the choice of using these techniques by farmers, only if it would maximise their productivity and optimise the use of rainwater which would in turn improve their livelihoods.

Irrigation

Other adaptive strategies gaining momentum are irrigation schemes. Burney et al. (2013) argues that small scale distributed irrigation schemes, such as community level catchments, tubewells, sprinklers and drip lines, has five-times the cost-benefit than large centralised irrigation schemes such as dams. Yol et al. (2011) found that the internal rate of returns for large-scale irrigation schemes averages to 7% whereas small-scale irrigation schemes have a rate of 28%. This is because small-scale irrigation can benefit more from areas with high rainfall potentials, unlike large-scale irrigation which may have lower rainfall rates. Other benefits of small-scale irrigation include being able to adapt these schemes to local needs and thus maximise freshwater use for agriculture, whereby many small scale farmers can access this resource.

Concluding Thoughts

There are many adaptive strategies that small scale farmers can adopt to mitigate the impacts of climate change on their agriculturally based livelihoods, ranging from soil based moisture conservation (mulching, manure, terracing and trenches), macro-catchment rainwater harvesting and irrigation schemes. These techniques have been adopted in indigenous practices and have long been sustaining the African population. But given the onset of climate change and the devastating impacts that it is predicted to have over Africa, the COP22 negotiations can elevate the importance of adaptive strategies to a higher level, which may attract investment and development of these adaptive strategies and farmer’s adaptive capacities. 

Adapting to Climate Change: Groundwater

Climate change largely influences surface water sources through altered rainfall patterns, evaporation rates and changing temperatures, whereas groundwater resources are more resilient to climate change and thus offers a reliable supply of water (Calow et al., 2010). Groundwater resources can provide an important buffer to climate change because despite aquifers being highly unevenly distributed across Africa, the smallest or poorest aquifers can still contain enough water for pumping to local communities during dry rainfall seasons or long periods of drought (MacDonald, 2012). In this blog, I would like to explore how groundwater resources respond to climate change and thus the role of groundwater resources as an adaptive measure.

Groundwater resources typically store a certain amount of water depending on the geology, geomorphology, and effective rainfall of the aquifer, which in turn influences the transmissivity, porosity, saturated thickness, and recharge rates of the aquifer (MacDonald et al., 2012). The largest aquifers in the African continent lies in the northern region, where countries like Libya, Algeria, and Egypt have the largest reserves of groundwater (Figure 1). Aquifers with lower storage capacities varies across the continent due to different rock formations; the lowest groundwater storages are underlain by Precambrian basement rocks (MacDonald et al., 2012). However, despite some areas having large or small storage capacities, the yield of the aquifer and borehole limit the productivity of these aquifers. The yield of a borehole or hand pump to the aquifer will limit how much water can be abstracted and used, therefore even though some countries have large aquifers, the productivity of these aquifers may be low where little water can be abstracted and used. Figure 2 shows the productivity of aquifers, and comparing this to figure 1 for example, shows that the aquifer underlying the South Sudan region has a relatively high groundwater storage of 25,000-50,000 mm, however it has a moderate productivity level of 1/5 ls^-1. 

Figure 1. Groundwater Storage (MacDonald et al., 2012)                         Figure 2. Aquifer Productivity (MacDonald et al., 2012)

Climate change rarely impacts the geology and geomorphology of groundwater resources; however, climate change directly influences groundwater resources through groundwater recharge processes (Taylor et al., 2012). The replenishment of groundwater resources relies upon recharge from either rainfall or the leakage from surface water resources. The IPCC’s fifth assessment report predicts that rainfall patterns are likely to become more highly variable, both spatially and temporally where droughts and intense rainfall periods are likely to occur (IPCC, 2014), and this in turn will likely influence groundwater recharge.

A study by Owor et al. (2009) attempted to determine a relationship between groundwater recharge and climate change using a rare set of data, which consists of daily rainfall and groundwater levels in the Upper Nile Basin of Uganda. The study related the magnitude of recharge events to the sum of daily and annual sum of daily rainfall exceeding a threshold of 10mm^-1, and they have found that groundwater recharge is better related to heavy rainfall periods, exceeding a threshold of 10mm^-1, compared to daily rainfall rates. Their conclusion of this analysis suggested that climate change may indeed have a positive influence on groundwater recharge because the predicted increased frequency in rainfall intensity can promote increases in groundwater recharge instead of restricting it. Similarly, another study by Mileham et al. (2009) found that groundwater recharge was higher when intense rainfall was accounted for when modelling the influence of climate change projections on groundwater recharge. A mean monthly delta factor of climate change was applied to the SMBM while using a historical rainfall distribution (period 1960-1990), groundwater recharge is projected to decrease by 55%, whereas runoff is predicted to increase by 86%. However, when this historical rainfall distribution is adjusted to account for the projected increase in intense rainfall patterns for a future period (2070-2100), groundwater recharge and runoff is predicted to increase by 53% and 137% respectively. Hence, this also shows that groundwater recharge is positively influenced by intense rainfall, and the distribution of daily rainfall is also an important factor when modelling groundwater recharge.

These studies have shown that the projected intense rainfall will likely improve groundwater recharge and thus the amount of groundwater stored. This in turn can prove to be a reliable source of freshwater, especially during periods of drought. An article by Oliver Balch (2016) agrees that the increased use of Africa’s aquifers can help to reduce water stress and insecurity. Initiatives by the International Water Management Institute and the Groundwater Solutions Initiative for Policy and Practice aims to enhance the use of groundwater resources for agricultural and domestic needs, to reach the UN Sustainable Development Goals in reducing water scarcity. However, the article stresses the importance of overexploitation and sustainable consumption of groundwater, noting that the Saiss aquifer water table has fallen by an annual average of 3meters over the past 20 years (Balch, 2016). It is important to recognise that despite groundwater being a reliable source and adaptive strategy to climate change, it is important that groundwater use is sustainable. A study by Knuppe (2011) conducted interviews with management experts in South Africa to determine the key challenges in the sustainable use and management of groundwater resources. Climate change will have uncertain consequences on groundwater resources but the stress and exploitation on this resource will increase due to the undervaluation of groundwater, the need for information at all levels in a community, the centralisation of power, governance and management, and the disregard for ecosystems and its services. A water planning expert, Callist Tindimugaya in the Balch article says that groundwater resources are an “invisible commons” because there is a lack of information amongst the people using this resource, and thus they do not comprehend how to use this resource sustainably. A lack of central planning and policies leads to inefficiencies, and ultimately poor management resulting in intensive and exploitative use of groundwater. Therefore, it is also important to consider the combination of socio-economic and physical context of using groundwater resources, especially when using groundwater as an adaptive strategy to climate change. 

Climate Change, Land Use and Agriculture

Agriculture is a very important aspect of many people’s livelihoods in Africa, and my previous blog explored the impacts of climate change on agriculture and the vulnerability of Africa’s population to these impacts. Addressing the impacts is definitely an important aspect to maintain people’s livelihoods, but now I am interested in exploring the future of Africa’s agricultural sector in terms of land use change. How does climate change influence the way land is used? What are the drivers for land use change and to what type of land use is being used? What are the implications on hydrological processes and water availability if land is increasingly being used for agriculture? These are some questions that I would like to explore.

Land use change and climate change are both factors that contributes to global environmental change, however, both of these factors affect each other (Dale, 1997). Firstly, land use change and patterns influences climate change due to changes in the atmospheric flux of CO2 and secondly, land use can be altered by climate change due to unfavourable conditions for certain human uses and activities. Hence, land use can be seen as a causal factor to climate change, but it can also be seen as an adaptive measure to climate change (Dale, 1997).

The World Bank estimates that as of 2013, approximately 43.86% of land in Sub-Saharan Africa is used for agricultural purposes. Agricultural transformation in Africa has an important role for economic transformation and in recent years Africa has seen large increases in investment by governments in this sector. Africa Agriculture Status Report (2016) explains that Africa’s agricultural sector is driving changes in Africa’s economic prosperity, and hence these socio-economic drivers will continue intensify the changes in land use for agricultural purposes. I will not go into detail about the history and development of Africa’s agricultural sector in this blog, but instead, I would like to highlight another an alternative driver of land use change in Africa. 

Ahmed et al. (2016) highlights the importance of climate change as another important factor in shaping agricultural land use. As previously mentioned, Dale (1997) explains that there is a dual relationship between land use change and climate change, and Ahmed et al. (2016) models both socio-economic and climate change factors as the drivers of Africa’s agricultural future. The study found that a reduction in crop yields caused by climate change, alongside an increasing demand for food in the future will inevitably result in an increase in land used for agriculture in West Africa to meet these demands. The eastern region of West Africa will experience a decline in both forests and grassland covers to cropland covers, whereas the western region will experience a larger decline in forest cover overall. The study projected that for Nigeria, average cropland cover will increase from 39.4 to 84.5% as a result of climate change, and an increase in crop cover of 37.3-40.9% is likely to occur along the Gulf of Guinea. These results show that under a purely climate change scenario, land use change will move from natural vegetation to crop cover, however, these results were determined without accounting for the adaptive capacities of farmers and communities. This study does mention these limitations and it was useful in attempting to show how much land will change as a result of climate change, but we cannot simply ignore the combination of other socio-economic factors and adaptive strategies of farmers to climate change scenarios, which this study concludes as the largest factor in driving land use change.

Changing land from one land cover to another is likely to have large implications on water resources, and especially in arid and semi-arid regions of Sub-Saharan Africa. Evaporation and runoff components of a catchment are usually influenced the most by land-use change, which in turn influences runoff and recharge rates into aquifers. A case study in southwest Niger shows that the water table has been increasing for many decades, despite there being a decline of 23% of the monsoonal rainfall seasons (Favreau et al., 2009). This was because land clearing of natural savannah to be used for millet crops had significantly increased surface runoff; the study modelled runoff and concluded that runoff had increased by threefold the normal rate, irrespective of climate conditions. Higher rates of runoff leads to higher recharge rates, the study found that recharge rates increased to 7mm/area after land was cleared compared to a rate of 2mm/area before land was cleared for crops. Not only does land use change influence rates of recharge and runoff, it also affects the quality of groundwater resources whereby there was a rising trend in nitrate concentrations by 4% (Favreau et al., 2009). Hence, when decisions are made to convert natural land to agricultural land crops, the impacts of this change needs to be carefully considered, especially because of the impacts of water resources and if these impacts will infringe upon the sustainability of that resource.

Concluding thoughts:

Land use change, climate change and water resources has more complicated drivers, interactions and consequences than has been explored in this blog. In this blog, I wanted to focus on the climate perspective of land use change and the consequences of this change, but despite making attempts to just focus on this perspective, I could not ignore the socio-economic drivers that influences land use change. Indeed, when analysing the drivers and consequences of land use change, one should look at both the human and climate factors of this change. Undoubtedly, land use change will have consequences on water resources such as groundwater levels and the quality of water resources and so farmers will need to carefully consider why they are changing land-use for agricultural purposes and if it will outweigh the consequences of water resources. 

Climate Change Impacts on Agriculture

In my previous blogs, I have discussed the impacts of climate change on rainfall patterns. In this blog, I want to explore how these changes in rainfall patterns will affect Africa’s agricultural sector and the economic and social consequences of changing agricultural yields and productivity.

A huge concern of climate change impacts in Africa especially is centred on food security. Food security is understood as the physical and economic access to safe and sufficient food to meet dietary needs (FAO, 2006) and climate change threatens to worsen food security conditions. Africa’s economy and people relies largely on agricultural products for their economy or sustenance and the prospects of climate change altering rainfall patterns poses a large threat to Africa’s agriculture because crop production relies hugely on rainfall to water their crops. Many large organisations such as the Food and Agriculture Organisation of the United Nations, the World Bank or the International Food Policy Research Institute (IFPRI), have all predicted that the prospects of Africa’s agricultural sector are bleak. For example, the FAO reports that rural development is expected to be hit hardest due to financial downturns and food crisis associated with loss in agricultural productivity. The FAO predicts that agricultural yields will reduce by up to 50%, and therefore, crop revenue will decline by as much as 90% by 2100 (FAO, 2009). The World Bank estimates that sensitive crops to high temperatures such as maize and wheat would be highly effected and thus crop yields will diminish. Furthermore, arable land would decrease by 40–80% (WorldBank, 2012). Similarly, IFPRI (2013) predicts that crops such as wheat will diminish in productivity, although increases in rainfall in certain areas are likely to experience slightly increased rain-fed maize and rice crops. Overall, these predictions share a common trend whereby crop productivity and yields are expected to decrease, and in conjunction with Africa’s population estimated to increase to 2 billion people within the next few decades (AfricaRenewal, 2014) will only worsen the food crisis and security in Africa. However, I should caution that the impacts of climate change on agriculture will vary across Africa just like how the impacts of climate change on rainfall patterns also vary across the African continent.

These predictions from the FAO or the WB are continent wide predictions which ignores regional scale differences, although, IFPRI estimates that Southern Africa is expected to be one of the worst hit by climate change due to rising temperatures and declining rainfall levels (2013). Countries like Malawi for example are predicted to see declines in average yields in maize productivity by 7–14% by 2050 due to an overall decline in rainfall (Msowoya et al., 2016). Countries in Eastern Africa are experiencing the same decline in crop productivity but in a different manner aside from an overall decline in rainfall. Instead, the Manyoni district in Tanzania are experiencing lower crop productivity due to unpredictable rainfall whereby delays or earlier onsets of the rainy season leads to poor germination of seeds and thus total crop failure (Lema & Majule, 2009). Moreover, problems such as increases in the number of pests and diseases contributes to declining crop productivity.

The consequences of declining crop productivity affect the social and economic conditions of countries in Africa. In Sub-Saharan Africa, agriculture accounts for up to 50% of GDP in most countries, however agricultural practices are small scale, has low inputs with limited use of fertilisers and high dependence on rainfall (Asafu-Adjaye, 2014).
Msowoya et al. (2016) study has identified a strong correlation between Malawi’s maize productivity and the national GDP. From 2000 and 2005, low rainfall levels reduced overall maize productivity and in 2005, maize production was 40% below the national average. This decline in productivity was followed by a large decrease in the national GDP production potential from maize. Given that Malawai’s food production is highly dependent on rainfall, and maize is a core crop in agriculture, the impacts of climate change has large ramifications on the socio-economic standing of Malawi. Lower productivity will inevitably increase the prices of crops and this can worsen conditions for poor groups of people who may no longer be able to afford to pay for crops. An overall decrease in crop productivity places stress of socio-economic development in areas that need it, and it also places stress in urban areas for alternative to agriculture employment opportunities.

Interestingly however, most agricultural output in Sub-Saharan Africa and the associated economic value is influenced not only by rainfall conditions, but technological and market conditions in Africa. The opportunities in agricultural output that fertilisers can provide are not seen due to the lack of using fertilisers because of its high prices (Asafu-Adjaye, 2014). Furthermore, farmers who does not have access to larger markets to sell their goods to, or the technology and means to store their goods effectively eliminates the potential of achieving high transaction costs due to the need to sell their products immediately. Rural markets are less likely to benefit from trading with larger markets due to segregation and isolation.

Concluding thoughts

The direct impacts of climate change such as the lack of rainfall as well as the temporally and spatially variable rainfall patterns has huge consequences on agricultural output, which is an overall declining trend across Africa. This can worsen economic and social conditions whereby the national economic output can decline; individual farmers have lower levels of income thus affecting social conditions such as the ability to pay for electricity or school and daily necessities. Moreover, lower agricultural output can result in the migration of people from rural farming lands to urban areas in search of other jobs, further complicate living conditions in these areas. There is no doubt that climate change has the potential to affect agriculture, but it is also important to recognise that human structures and policies can play a large part in an agricultural economy, and the vulnerability of small scale and large scale farmers. 

Climate Change and Rainfall: Part II

My previous blog explored the impacts of climate change in rainfall in terms of droughts, and more specifically in West Africa and the Sahelian region. This blog continues to explore the impacts of climate change in Africa but in terms of floods. The first thing that comes to my mind when I associate climate change with rainfall in Africa are the ideas of drought and famine, thus ideas concerning extreme rainfall and increased flood extent, I find, is very intriguing. In this blog, I want to look at floods associated with climate change and the impacts.

The dominant projections of climate change impacts on rainfall in terms of extreme rainfall and flooding events is that rainfall is more likely to become highly variable in East Africa, extreme rainfall events will become more frequent and thus result in more flooding (IPCC, 2007). Studies such as Webster et al. (1999) and Hastenrath et al. (2007) have found that in fact, East Africa has experienced both extreme rainfall as well as a lack of rainfall in the region. This anomalous extreme rainfall results in more flood events, and the frequency of flood events has increased in recent years. Shongwe et al. (2009) analysis of the International Emergency Disaster Database shows that almost 7 events per year of reported disasters, which was related to increased flooding, had occurred from 2000 to 2006. The impacts of these disasters affects economic development, poverty reduction and the well-being of an average of two million people per year (Shongwe et al., 2011). Shongwe et al. (2011) notes that the predicted impacts of global climate models are already occurring now, much sooner than anticipated. And so, the impacts of flood risk need to be analysed, and management of flooding regimes must be properly accounted for. Just because there is an expected increase in East Africa does not mean that this is necessarily a good thing.

The coastal city of Mombasa is located in Kenya and currently experiences frequent floods on a near-annual basis, however the October 2006 flood was one flood that Mombasa did not usually experience. This flood was induced by extreme rainfall which saw the destruction of important infrastructure, such as collapsed and flooded roads which can be seen in the image below, and more than 60,000 people was affected by the flood (Awuor et al., 2008). The impacts of this large flooding event worsened the social and economic conditions of the city due to the major economic losses associated with infrastructure damages, as well as the damages to fishing vessels. A large majority of Kenya’s coastal population is concentrated in Mombasa – this increased the risk of the spread of cholera (Awuor et al., 2008). The city was notified of a cholera alert whereby thirteen cases were found positive for cholera and an addition of two deaths by the 11 November 2006 (OCHA, 2006). Moreover, between 15^th and 17^th October, high rainfall levels of 110mm resulted in landslides which saw the death of five children.
The impacts of flooding are very severe in the short run in that homes are almost instantaneously destroyed, many people are displaced and the death rates of populations are widespread and the causes of these deaths range from drowning, debris or from water-borne diseases like cholera. These impacts only proves to show that flood management in vulnerable places is integral in a warming world.

 Image 1 (Left) and 2 (Right) 

There is no doubt that the increases of the number of floods in magnitude and frequency are causing huge damages to infrastructure, economic performance and livelihoods. However, some argue that the damage and extent of flood events is more than just the increased intensity and magnitude of floods as a result of climate change in recent years. Studies such as Baldassarre et al. (2010) concluded that at continental and site specific scales across Africa, the impact of climate change in this observed increase in flood damages is negligible. Instead, Baldassarre et al. (2010) attribute the increased damages of floods to higher rates of urbanisation in the last decade. They found that an increase in urban population by magnitude of 1 also saw the increase of fatalities caused by floods by a magnitude of 1. Many studies (Hardoy et al., 2001; Douglas et al., 2008; Jonkman, 2005) concluded that the increased potential of flood risk with severe and irreversible consequences is a result of intensive, rapid and unplanned urbanisation in the number of people living in floodplain areas (Balassarre et al., 2010). For example, the growth of the capital city of Lusaka in Zambia is prone to flooding, thus this growing city is expected to have higher risks to flooding (Nchito, 2007).

Concluding Thoughts:

It is very important to not take these projections of increased flood frequency and magnitude lightly, given that they are currently happening now and not in some far distant future. Proper flood management is required to minimise the impacts of these floods induced by climate change. However, as many studies found, it is difficult to isolate and differentiate the increased flood damages as a result of climate change only. Other human factors showed to account for a large part of this increasing damage, even in a globally warming world. Even though climate change may induce frequent floods, climate change should not be seen as the only cause of the increased impacts of floods in many African towns and cities. Overall, compared to droughts, the impacts of floods on many people can be minimised with the proper management of drainage systems and the construction of towns in a rapidly urbanisation, as well as working in tandem with monitoring rainfall patterns and thus predicting then floods are likely to occur as a result of intense rainfall periods. 

Climate Change and Rainfall: Part I

Rainfall is extremely important in Africa because most of people’s livelihoods are based on agriculture (Thorton et al., 2008). Agriculture is mainly rain-fed and hence, is highly sensitive to extreme weather conditions such as droughts, floods, intense rainfall and high temperatures (Molua, 2002).
As mentioned in the previous blog, many reports and models (IFAD, 2009; IPCC, 2007) explain that climate change is expected to have an adverse effect on rainfall patterns, and the largest impact being in Africa due to their high dependence on agriculture, harsh environments and weather conditions, and low adaptability (Dinar et al. 2008). Rainfall is expected to decrease in northern, southern and west Africa, due to increasing temperatures and evapotranspiration (IPCC, 2008). East African rainfall is expected to increase and become more variability and intense rainfall events are likely to be more frequent. Also, central Africa is expected to have more variable extreme weather events. These models and predictions are only estimations of what is ‘likely’ to happen so there are high levels of uncertainty, especially of how the impacts of climate change operate on a regional and local scale. Thus, this blog will look at the regions that are expected to experience decreases in rainfall variability and droughts.


Recent studies have observed the current trends in rainfall patterns over different regions of Africa, and most studies have found that while increases in rainfall availability have occurred in some areas, decreases in rainfall is somewhat more notable (Kotir, 2011).
Southern Africa experienced a declining trend of rainfall has occurred over the last 25 years and one of the worst droughts in Southern Africa occurred in the 1991/1992 season, where water systems and dams have failed, and emergency boreholes was set up to provide some amount of water supply (Magadza, 1994). Joubert et al. (1996) have found that the number of droughts are expected to decrease in the sub-continent of southern Africa, however when droughts do occur they’re expected to be more severe.
In West Africa, Agumagu (2016) have found that the Sahel region of West Africa experienced long term declines in precipitation during the first and last half of the 20th century. The low precipitation levels in the northern region of the Sahel is linked to climatic changes. Hulme et al. (2001) found declines of about 20–40% of rainfall in the same region of West Africa, and declines in other parts of Africa is widely variable from 5–49% since the 1960s. Overall declines in precipitation can be seen in figure 1.

Figure 1. Indices of Sahel rainfall variability. (Giannini et al., 2008)

The result of declining rainfall in the Sahel have led to many droughts, e.g. Giannini et al’s (2003) study linked the droughts to the warming of tropical oceans, and hence attributed the late 20th century drought to global warming. Biasutti & Giannini (2006) ocean-atmosphere model (CMIP3 in IPCC AR4) and Rostayn & Lohmann’s (2002) study showed that anthropogenic activities, and thus climate change, had influenced rainfall and drought conditions in Africa by modelling and linking greenhouse gases and anthropogenic sulphate aerosols to a reduction of tropical rainfall and subsequently the drying of the Sahel. However, these studies can insofar attribute the role of industrialisation and aerosol emissions on changing rainfall patterns in Africa (Giannini et al., 2008). This is because these models tend influence of other climate processes such as ENSO on African rainfall, and land-atmosphere processes or the role of biomass in temperature and rainfall controls (Hulme et al. 2001).

An interesting study by Mertz et al. (2009) attempted to analyse rural farmers’ perception of climate change in the Sahel region, and results largely show contrasting perceptions to the IPCC portrayal of the impacts of drought. The IPCC attributed negative impacts of droughts to crop failure because of low rainfall levels. Interestingly however, the main ‘negative’ impacts of droughts that was mentioned the most was excessive rainfall and strong winds, being mentioned 14 and 30 times respectively, compared to a lack of rainfall that was mentioned only eight times (Mertz et al., 2009). Clearly this shows that despite mainstream views of agriculture being affected the most due to low rainfall, other problems are more important to small scale farmers who live in Africa and experiences these conditions daily. Hence, we can interpret that farmers are more resilient to less rainfall, due to adaptive measures such as planting new cops and varieties (e.g. vegetables) or replacing horses with cattle which is cheaper to feed and the use of manure to counter agricultural problems. But these rural farmers are less resilient to e.g. strong winds that causes damage to their millets, roofs and houses which also effects their livelihoods, not just a lack of rainfall.

Concluding Thoughts:

Projections of changes in rainfall variability by reports such as the IPCC AR4 across Africa have shown to be evident in many studies whereby droughts in the Sahel or southern Africa are becoming more frequent or limited in frequency yet severe in severity. Although the results of these studies, and especially those that use models should be carefully considered because these results may exclude certain processes and relationships that is very important in rainfall processes over Africa and so one should question if the links of declining rainfall to climate change are robust. This blog focused mainly on droughts in the Sahel region of west Africa because I found the responses of farmers to the droughts in Sahel to be very interesting and it made me change my views of the needs of farmers, and not just their ‘adaptability’ to climate change. Conventional ideas of reduced agricultural yields appeared to be the most devastating impact on farmers and thus their livelihoods, and I usually submit myself to accepting this common ‘impact’ of climate change on small scale farmers. However, the contrasting opinions of these rural farmers greatly informed me of the different needs that these farmers have and not just their agricultural yields, such as their homes and infrastructure; these farmers already appear to be well equipped to droughts. 

Variability in Africa's Physical Environment and Climate Change Impacts

Diverse Africa 

Aside from Africa’s pretty green scenery and a wide array of exotic animals, Africa is highly diverse and variable across space and time in a number of physical attributes such as biomes, precipitation patterns, topography and groundwater resources. The Hadley Cell of the atmospheric circulation over Africa results in a desert type biome in the north and south, and a tropical biome in the centre of Africa (Figure 1) due to high pressures at higher latitudes of 30°N and 30°S, and low pressure near the equator which facilitates high levels of rainfall in the tropics (Figure 2). African climate is largely determined by the interaction of three large-scale climate systems, the ITCZ, El Nino-Southern Oscillation and annual variability of Monsoon systems (Conway, 2009). The ITCZ has an extremely important role in distributing rainfall temporally and spatially over Africa. Elevation levels vary across the continent where there is low elevation in the north-east and high elevation in the south-west (Figure 3). Groundwater resources are underlain by different geological rock types and thus affecting different productivity levels (Figure 4). It is the complexity of Africa’s physical environment that should be carefully considered when discussing the impacts of climate change. 

                   Figure  1. Biomes of Africa (UNEP)    Figure 2. Precipitation patterns of Africa (UNEP)

                        Figure 3. Elevation of Africa      Figure 4. Geology of Africa (MacDonald, et al., 2012)

What is climate change?

The IPCC explains that climate change is a result of anthropogenic influences on natural climate systems and thus forcing them to change (IPCC, 2014). A major cause for climate change is due to increases in anthropogenic carbon dioxide emissions during the industrial era of the mid-20^th century and since then the subsequent economic and population growth (IPCC, 2014). Brian Kahn (2016) reports that September 2016 is a milestone in the world’s climate whereby carbon dioxide levels have surpassed the ‘symbolic’ mark of 400 ppm. The IPCC’s Fifth Assessment Report explains that we can expect more variable rainfall patterns and temperatures across Africa (Niang et al., 2014), and thus surpassing the 400ppm mark can only make these patterns more variable than ever. In a world where governments and international organisations have finally come together to tackle climate change, it just clearly shows that our current methods appear ineffective and more work is required when facing this challenge. 

Brief Overview of the Impacts of Climate Change on Africa

• Increased frequency in extreme rainfall (New et al., 2006) – IPCC (2014) for example, explains that southern Africa is experiencing increases in extreme rainfall and New et al. (2006) has shown statistically significant relationships between extreme precipitation and total precipitation whereby increases in extreme precipitation and decreases in total precipitation show that average intense rainfall is concentrated on extreme rainfall days in southern and western Africa.
• Increased frequency and intensity of droughts and floods in some regions – It is more likely that the southern and northern most parts of Africa will become hotter and drier where temperatures are projected to increase by 4°C and rainfall levels are expected to fall by 10-20% (IPCC, 2007). The IPCC AR5 suggests that temperature across Africa is likely to rise more quickly than other land areas and this is most pronounced in arid areas.
• A decrease in perennial stream or river drainage density (de Wit & Stankiewicz, 2006) – Regions receiving more than an average of 1000mm of rainfall per year and experiencing a 10% in precipitation will see a decrease in drainage by at least 17% (Figure 5). Areas with 500mm of rainfall would see a drop of 50% in surface drainage with a 10% decrease in precipitation (de Wit & Stankiewicz, 2006). Central and eastern Africa is expected to see increases in precipitation whereas precipitation in northern and southern most areas Africa is expected to decrease. 

Figure 5. Drainage density and rainfall (de Witz & Stankiewicz, 2006)

• A reduction in agricultural crop yields – General consensus of climate change impacts on agriculture shows that rain-fed crop yields are expected to fall by up to 50% by 2020 in many African countries where small scale farmers are expected to be most affected (IPCC, 2014). Roudier et al. (2011) predicts that Sudano-Sahelian countries in north-western Africa is likely to be more affected (median yield loss of –18%) than Guinean countries in south-western Africa (–13%). However, Roudier et al. (2011) also found that higher carbon fertilisation processes have the potential to improve yields for C3 (e.g. soybean) and C4 (e.g. staple crops like maize) crops. In East Africa, Thorton et al. (2009) predicted that maize yields and bean yields are likely to increase in the east African highlands such as the Kenyan and Ethiopian highlands. 

The impacts of climate change are world-wide but the same cannot be said for Africa; it is unlikely that there will be a wide African-scale effect of climate change. Instead it is more likely that climate change effects will vary within different locations of Africa due to its large landmass and heterogeneous physical and environmental features (Collier et al., 2008).

Concluding thoughts:

Africa consists of highly diverse and variable physical attributes, such as rainfall patterns, temperature, land surface geology, and elevation. Thus we should not assume that the impacts of climate change in Africa is simply homogenous on a wide continental scale, instead the impacts of climate change are regionally localised to the environmental conditions of that area. Impacts on the hydrological cycle include extreme rainfall patterns, overall decreased rainfall levels, flooding, and droughts are likely to occur unevenly across Africa.

Although the use of the term impact should be carefully considered – the impact of climate change on the hydrological climate is negative, however climate change impacts also appear positive in other areas such as carbon fertilisation processes.
Thus this blog will continue to explore the impacts of climate change on water resources and systems in Africa, and thus the impacts on people’s well-being and livelihood in Africa. 

Environmental Change and Water in Africa: An Introduction

I will be focusing on the influence of environmental change, namely climate change, on water resources and availability in Africa. Water is an incredibly important resource that is used in a variety of ways ranging from having a shower to washing your car, making and dyeing the colour of your clothes in industries and large scale agricultural practises to feed the people of the world. 

Water resources in Africa is highly variable across space and time, and so the reality of climate change will significantly influence the hydrological cycle. Impacts include changes in rainfall frequency and distribution, water supply and quality. 

Thus this blog will explore how the influence of climate change on water resources impacts people, agriculture, industries and economies through the discussion of academic articles, new articles and videos.