**3. Impact of climate hazards on agricultural sector in Rwanda**

Climate change has the potential to threaten agriculture through its effects on soil properties and processes [10]. Thus, the soil degradation implies decline in the quality and capacity of soil to perform its function. Qafoku [11] reveals that climate change, i.e., high atmospheric carbon dioxide concentration (≥400 ppm), along with increasing air temperature (2–4°C or greater) that persist for an extend period of time, significantly affect soil proprieties and fertility, thus agriculture sector fails in providing food quantity and quality. Furthermore, Islam and Wong [12] points out that, changes in the carbon dioxide concentration in soil affects the organic matter content of soil and soil quality, resulting in soil degradation. In return, Soil degradation reduces the output of agriculture and the efficiency of inputs.

It is crucial to consider the the impact of changing climate on soil in Rwanda, in order to cope with it. According to Famine Early Warning Systems Network [13] Rwanda is ecologically diverse with highland mountain forests, savannah grasslands, and lowlands. The western part of the country is characterized by highland mountain landscapes and gentle slopes leading toward the lowland areas in the east.

Rwanda is divided into twelve zones excluding Kigali city which is considered as an urban area and they offer a form of economic geography adapted to food security analysis. These livelihood zones are defined on the basis of local economies and livelihood opportunities, National Institute of Statistics of Rwanda [14], and are regularly used to analyze food security in Rwanda [13].

According to the 2018 analysis of food security and vulnerability in Rwanda conducted by NISR, the three eastern livelihood zones, namely, Bugesera Cassava Zone; Eastern Agro-Pastoral zone and Eastern Semi-Arid Agro-Pastoral zone are areas prone to drought conditions which prevent farmers from performing well in their farming activities. Besides, there is East Congo-Nile highlands subsistence farming zone that is at risk of prolonged dry spells as well as severe flooding. This zone is located in a high altitude mountainous area of Rwanda Southern Province. As the Eastern Semi-Arid zone, East Congo-Nile Highlands zone suffer from poor roads conditions and steep terrain which impede access to markets during the rainy seasons, the period when landslides occur more frequently. These conditions prevent farmers from selling their products.

Moreover, Ministry of Foreign affairs [15] notes that the mountainous west of the country constitutes a subject to erosion, part of central north and south experience severe floods, and the east and south suffer from droughts and desertification.

The consequences are not only seen on production but also on the demand of labour. Especially, poor households are at risk of food insecurity since they rely on their own production which is done in small plots of land, in-kind payment and market purchase mainly through agricultural activities/labour to meet most of their annual food needs.

#### **3.1 Vulnerability of agricultural sector in Rwanda**

The vulnerability of the agriculture sector in Rwanda is found in the characteristics of the country's topography. The western part of the country is dominated by highland mountain landscapes and gentle slopes while the eastern is consisted of lowland areas. These conditions make the whole country's arable land susceptible to severe landslides, erosion and floods. Another challenge is the demography of the country, which constitutes one of the most densely populated in the region. In addition, there is limitation in ability to cultivate with climate smart related options coupled with small size plot hold by farmers.

According to REMA [5], agriculture is highly sensitive to climate change and extreme weather conditions such as droughts, floods and severe storms. This is so in Rwanda, since all farming activities are dominantly rain-fed. In line with the observation of REMA [5] several factors account for the direct connection between climate change and agriculture productivity. These include average temperature increase, changes in rainfall amount and patterns; rising atmospheric concentrations of CO2; pollution levels such as tropospheric ozone; climatic variability and increase in frequency and intensity of extreme events such as droughts, floods, intense and destructive rains, as well as other related events such as landslides.

As observed by Mutabazi [16] rainfall behavior shows that the rainy seasons in Rwanda are becoming shorter with higher intensities. As a result, there are events such as floods and landslides in areas experiencing heavy rains; and drought in dry areas. This tendency leads to decrease in agricultural production. For instance, heavy rains that have been observed in the northern and the western provinces coupled with a loss of ecosystems services due to the deforestation have resulted in soil erosion, rock falls, landslides and floods which destroy crops. On the other hand, the eastern province has been experiencing rainfall deficits over the decade of 2000–2010, leading to droughts.

The impact of climate change on agriculture and allied sectors in Rwanda is presented in **Figure 1**.

As REMA [5] observes, there are some climatic conditions which have increased crop growth vulnerability. First of all, the shifts in rainy seasons (September– December) and (March–May) and short or prolonged dry seasons in some regions distort growing seasons. This usually confuses farmers on critical decisions such as planting dates, which affects the timing of field preparation and planting in turn. These also affect crop growth, cause intensification of crop diseases and pests and result in lower crop yields. For instance, the shift in rainfall patterns leads to reduction in the amounts of rain water harvested therefore affecting both hillside and valley irrigation projects, through either decreased water levels in ponds/dams or high amount of water destroying dam/pond embankments and causing erosion and silting. Sometimes, the high amount of rainfall destroys the quality of the soil and affects the growth of crops.

For instance, REMA [5] highlights the floods observed in the Northwest and in the marshes of the River Valleys of Nyabugogo and Akanyaru in Rwanda resulted in loss of food production, property destruction which usually leave the farmers homeless and without food. Besides, they lead to serious soil erosion and destruction of irrigation infrastructure both on the hill slopes and down the valleys.

*Droughts and Floodings Implications in Agriculture Sector in Rwanda: Consequences of Global... DOI: http://dx.doi.org/10.5772/intechopen.98922*

#### **Figure 1.**

*Climate change effects and related impacts in the agricultural and allied sectors. Source: Adapted from [5].*

Another major factor of vulnerability that REMA [17] showed is the prolonged and cyclical droughts. This drought is encountered in the Southeast of the country resulting from decreasing annual rainfall amounts (from 1000 mm to 700 mm) which leads to food insecurity and displacement of communities. Moreover, this calls for relief supplies and resettlement which would have budgetary implications. On the other hand, REMA reported that since 2011, the intense rains in the Northwest and the droughts and erratic rainfall in the districts of Bugesera, Nyanza, Gisagara, Huye, Rusizi-Nyamasheke have affected over 60–90% households. These climate hazards do not only affect food production, but also results in food and nutrition insecurity.

#### **3.2 Droughts**

As a result of global warming, Rwanda's drought vulnerability is observed to be high. Mutabazi [16] notes that drought; irregular rains and dry spells were the most commonly reported shocks for households. For instance, drought made the Southeast region vulnerable where decrease in annual rainfall as well as prolonged and cyclical droughts led to food insecurity.

Drought mostly affects the agro-bioclimatic regions of the East and Southeast of the country and sometimes some zones of the Central plateau. For example, Bugesera used to receive rainfall amounts between 700 and 800 mm/year before the 1990s but in the 2000s; it only receives 300 mm/year which is more that 70% of water deficit. As a result, the production of cereals and leguminous plants such as

maize and beans has become almost impossible in this region. Another consequence of drought is the proliferation of parasites like caterpillars on sweet potatoes and predators of beans [18]. These parasites prevent crops from growing normally leading to low production which increases the risk of food insecurity in the country.

For example, NISR [14] shows that severe drought in the main growing seasons (A and B see **Figure 1**) impact between 28,500 and 157,700 people in all seven districts of the Eastern Province (Kayonza, Gatsibo, Kirehe, Nyagatare, Rwamagana, Ngoma and Bugesera). Moreover, the analysis highlights that about 62,000 MT and 157,700 MT of major crops are vulnerable to severe drought in season A and season B, respectively. Among these major crops such as banana, cassava, and Irish potato are the most vulnerable.

#### **3.3 Flooding**

The Global Facility for Disaster Reduction and Recovery (GFDRR) associated with the World Bank [19] state that floods are most frequent disasters in Africa. This may be a result of number of transboundary river systems located in Africa in addition to 160 major fresh water lakes and several small rivers, consequently this situation leads to frequent seasonal floods. Moreover, the report further notes that the impacts of natural disasters such as floods and landslides among others are further exacerbated by the weak flood protection, insufficient urban drainage systems, and increased run off caused by land degradation and poorly planned development.

Concerning landslides, Kervyn *et al.,* [20] highlights that landslides constitute a major hazard in many mountainous and hilly regions. Obura [21] weigh in by advancing the view that in countries with hilly terrain and high levels of rainfall, landslides risk is high due to widely prevalent soil erosion, deforestation and unsustainable land management which constitute the main causes of landslides in Africa. Rwanda is a good example in these case. Rwanda is in the African Great lakes region and is highly elevated; its geography is dominated by mountains in the west and savanna to the east, with numerous lakes throughout the country, where does the nickname "country of a thousand hills' come from.

Ministry of Environment [6] describes the relief of profile of Rwanda as follow: Rwanda is hilly and mountainous with an altitude varying between 900 m and 4507 m above sea level. The components of that relief are: Congo Nile Ridge Overlaying Lake Kivu with an altitude between 2500 m and 3000 m, it is dominated in the Northwest by the volcanic ranges consisting of five volcanic massifs of which the highest is Karisimbi itch 4507 m. The central plateau presents a relief of hills with an altitude ranging between 1500 m and 2000 m. The lowlands of the East are dominated by a depression characterized by hills with a more or less round top and 1000 to 1500 m in altitude. And the lowlands of the South-West in the Bugarama plain with an altitude of 900 m are part of the tectonic depression of the African Rift Valley [6].

According to MINITERE [18], in Rwanda, the most frequent direct risks to which agriculture is exposed are related to flooding and landslides. Erosion affects at least 50% of all farmers with a 30% decline in farm productivity while deterioration of soil is detrimental to Rwanda's food security for over 90% of the people who depend solely on agriculture in the country [16]. Soil erosion contributes to the decrease of agricultural productivity, causing therefore food insecurity problems. Floods, landslides and collapses are acute in regions with high altitude. These are dominantly in the west, southwest and north and central regions of the country.

*Droughts and Floodings Implications in Agriculture Sector in Rwanda: Consequences of Global... DOI: http://dx.doi.org/10.5772/intechopen.98922*
