ABSTRACT

Climate variability is a major issue affecting the global agro-hydrological environment, as well as the human systems. The Koutaba Municipality, located in the West Region of Cameroon, is a significant agricultural area. The inhabitants of this region rely heavily on agriculture for their livelihoods. Climate variability has a profound effect on agricultural productivity. This study examines the impact of climate variability on hydrology, agricultural productivity and livelihoods of the population in the Koutaba Municipality. With a focus on agro-hydrological effects, the study analyzes the relationship between changes in rainfall patterns, agro-hydro-meteorological droughts, and floods and agricultural productivity.

The study used both quantitative and qualitative data to assess the impact of climate variability on crop yields, land use, and farmers’ incomes. Both primary and secondary data (questionnaires, interviews, observations and information from published sources) were collected and analyzed. Results revealed that there has been a decreasing rainfall trend from 1960-2021 and increasing temperatures with recurrent dry spells at the beginning of the growing season. The mean annual rainfall stands at 160.2 mm, with a mean annual temperature of 23.32^oC, a mean Standardized Precipitation Index (SPI) of 0.2 (moderately wet), and rainfall coefficient of variation (CV) of 11.86% (reliable). T

he magnitude of climate variability stands at (26.7%) (moderate) this high magnitude is driven by anthropogenic activities (39.2%) and natural factors (32.5%) on the other hand which account for high magnitudes. This has led to farmers adapting to support their livelihoods against climate variability such as the use of fertilizers (50%), and irrigation during the dry season (55.83%), and some have resulted in alternative non-farm income activities (65.0%). From the Product Moment Correlation analysis, human drivers of climate change have proven to be the major cause of climate variability as human activities contribute the highest to the amount of local greenhouse gases in the atmosphere as well as natural drivers though to a limited extent. Climate variability has a significant negative impact on agricultural productivity and livelihoods in Koutaba, particularly among small-scale farmers. The study concludes that adaptation measures at the local, national, and international levels are essential to address the challenges posed by climate variability and support sustainable agricultural development and livelihoods in Koutaba.

CHAPTER ONE

GENERAL INTRODUCTION

1.1 The Research Context

In recent years, and particularly since the outcome of the second and third assessment reports of the Intergovernmental Panel on Climate Change (IPCC, 2001), it has become clear that global climate variability and change is a scientific reality. An increasing awareness that global climate change will affect water resources has also clearly emerged and this has been reflected in a rapidly growing body of scientific literature (Da Cunha et al., 2005). Climate variability results in significant impacts on water availability and safety (Tume, 2023). Every year, millions of people are affected by droughts and floods (Ludwig et al., 2009). It can also be noticed that these climate differences are also instigated by man in an attempt to make life better for them. According to the IPCC (2021), human influence has warmed the climate at a rate that has been unprecedented in at least the last 2000 years and has continuously been provoked by emissions from human activities which threatens and increases rates of global warming by day, evident by temperature changes from individual components of human influence: emissions of greenhouse gases, aerosols and their precursors; land-use changes (land-use reflectance and irrigation) and aviation contrails.

This study falls within section 3.6 of Cameroon’s National Development Strategy (NDS-30), where authorities plan to: strengthen actions relating to sustainable management of natural resources (soil, flora, fauna, water); and take adequate measures to adapt to and mitigate the effects of climate change. In addition, to address the noticeable consequences of climate change, the Government is committed to ensuring that climate change concerns are taken into account in sectorial strategies and policies, both in formulation and implementation; building the capacity of institutions responsible for climate surveillance to operationalize the system for monitoring, preventing and responding to the effects of climate change; develop and implement a national waste management strategy while promoting corporate social responsibility. At the global level, this study falls within the context of some United Nations Sustainable Development Goals, especially, SDG-2 (zero hunger), SDG-6 (clean water and sanitation), as well as SDG-13 (climate action).

Climate variability includes all the variations in the climate that last longer than individual weather events, climate and agriculture are highly interlinked, and one affects the other in many ways. According to the report of the Intergovernmental Panel on Climate Change, 2021, the frequency and intensity of heavy precipitation events have increased since the 1950s over most land areas for which observational data are sufficient for trend analysis, and human-induced climate change is likely the main driver. Human-induced climate change has contributed to increases in agricultural and ecological droughts in some regions due to increased land evapotranspiration. Climate variability and associated extreme events are causing significant damage to life, property, natural resources and the economy by affecting climate-sensitive sectors such as agriculture (Fanka, 2020).

The United Nations Environmental Program 2020 report, mentioned that climate change is increasing the frequency and intensity of extreme weather events such as heat waves, droughts, floods, and tropical cyclones, aggravating water management problems, reducing agricultural production and food security, increasing health risks, damaging critical infrastructure and interrupting the provision of basic services such as water and sanitation, education, energy and transport. Looking at the statistics provided by the report, global emissions of CO₂ have increased by 50% since 1990, oceans have also warmed, the amounts of snow and ice have diminished and sea levels have risen. From 1901 to 2010, the global average sea level rose by 19cm as oceans expanded. The emissions have also significantly grown quickly from 2000 to 2010 than in previous decades. Climate change is already affecting every inhabited region across the globe, with human influence contributing to many observed changes in weather and climate extremes (IPCC, 2021).

The IPCC technical paper on climate change and water indicates that freshwater resources are vulnerable and have the potential to be strongly impacted by climate change, with wide-ranging consequences for human societies and ecosystems based on observational records and climate projection, (UNFCCC, 2011). Climate change is projected to reduce renewable surface water and groundwater resources significantly in most dry subtropical regions. This will intensify competition for water among agriculture, ecosystems, settlements, industry, and energy production, affecting regional water, energy, and food security. In contrast, water resources are projected to increase at high latitudes. Proportional changes are typically one to three times greater for runoff than for precipitation. The effects on water resources and irrigation requirements of changes in vegetation due to increasing GHG concentrations and climate change remain uncertain (Arnel et al., 2014).

Climate variability is likely to increase the frequency of meteorological droughts (less rainfall) and agricultural droughts (less soil moisture) in presently dry regions by the end of the 21^st Century. This is likely to increase the frequency of short hydrological droughts (less surface water and groundwater) in these regions (medium evidence, medium agreement. Projected changes in the frequency of droughts longer than 12 months are more uncertain because these depend on accumulated precipitation over long periods. There is no evidence that surface water and groundwater drought frequency has changed over the last few decades, although the impacts of drought have increased mostly due to increased water demand. Climate change is projected to reduce raw water quality, posing risks to drinking water quality even with conventional treatment. The sources of the risks are increased temperature, increases in sediment, nutrient and pollutant loadings due to heavy rainfall, reduced dilution of pollutants during droughts, and disruption of treatment facilities during floods (IPCC 2014).

It is anticipated that climate change will have both global and local effects on the Earth’s surface. One of these effects will be a decrease in the availability of fresh water, leading to an increase in water demand (Kusangaya et al., 2014; Lespinas et al., 2014). Access to clean drinking water, sanitation, and water for irrigation is already a significant issue in the developing world, particularly in the vast semi-arid regions of Central Asia and Africa. It is expected to worsen as population growth and climate change exacerbate existing inadequate delivery systems and dysfunctional management institutions (Stakhiv and Pietrowsky, 2013).

With the increasing effects of climate variability such as increases in surface temperatures, changes in the amount of precipitation, changes in the frequency and intensity of extreme events, changes in the humidity of the atmosphere and shrinkages in sea levels and streams, this has made the management of water resources to be a very important issue (Borgomeo, 2015). It is this regard that led to the establishment of the IPCC in 1988 under the meteorological organization and the United Nations Environment Program to understand nature and the effects of climate change and to determine mitigation and adaptation strategies for climate change (Borgomeo, 2015). This institution has led to the establishment of many water management institutions in different parts of the World Cameroon is part of them with the West Region of the country not exempted from effectively managing water resources in the areas and putting forth strategies to cope with the increasing effects of climate change and to propose measures that can help reduce the causes of climate variability.

Of the total annual crop losses in world agriculture, a large percentage is due to direct weather effects such as drought, flash floods, untimely rains, frost, hail, and storms. Losses in harvest and storage, as well as those due to parasites, insects, and plant diseases, are highly influenced by the weather (Mavi, 1994). The agricultural industry is the most sensitive to variability in weather and climate. The average yearly temperature in Cameroon has risen by 0.7oC since 1960, with an average increase of 0.15^oC per decade (McSweeney et al., 2006). The rate of increase is highest at 0.19^oC per decade across the entire country. However, in the Northern part of Cameroon, the warming is most significant in December, January, February, September, October, and November, occurring at rates of 0.2 to 0.4 per decade. Meanwhile, the average annual rainfall has decreased by approximately 2.9mm per month since 1960 (McSweeney et al., 2006).

Koutaba which is found in Cameroon in the West Region, also suffers a great challenge in terms of water shortages as is the case in other parts of Cameroon. The main source of potable water for the local population is from wells which are often not harnessed and or protected. These wells are affected by seasonal changes because during the dry season, most of these wells dry up reducing the available supply of water to the locality meanwhile during the rainy seasons, the volume of water is said to increase as nearby areas are sometimes flooded. These variations in the flow of water have led to water management challenges, which therefore call for sustainable management of the water resources.

1.2 Statement of the Research Problem

Climate variability, including changes in temperature and precipitation patterns, has led to considerable agro-hydrological changes that impact the livelihoods of millions of people in the world. Agriculture plays a significant role in sustaining human livelihoods. However, climate variability has affected agriculture in many ways, particularly in Cameroon and the western region of Koutaba Municipality. The interrelationship between agriculture, hydrology, and climate is well documented, and changes in one component can have profound effects on the others. These effects are particularly felt in the agricultural sector, which is susceptible to even small changes in hydrology.

Water resources are directly related to the long-term climatic variations. Wells, streams and springs which are the main sources of water in Koutaba show signs of drying up in periods of extreme temperature conditions (dry season). There have been disruptions in the local hydrological cycle in the study area which is attributed directly and indirectly to human activities that alter the composition of the global atmosphere which is in addition to natural climate variability observed over comparable time. The increasing need for water resources and other resources directly linked to water such as agriculture which involves the cultivation of crops such as water (needs % water), tomatoes, rice, beans, pear, cocoyam, vegetables, and sweet potatoes which are the most cultivated within the Koutaba Municipality. Rearing of animals such as cattle, sheep and goats is also done within this community; poultry is also a dominant form of agriculture within this geographical area. This on a large scale, calls for more water use by farmers and livelihoods that are directly linked to water. However, the needs are not being fulfilled due to increasing water scarcity and farmers have been affected. Some of the factors that have contributed to water scarcity include: an increase in population and the water demand has drastically increased. Deforestation, which is often caused by human activities such as logging and farming, has contributed to climate variability. Trees absorb carbon dioxide, and when they are cut down, this carbon is released into the atmosphere. Deforestation also reduces the amount of shade and evapotranspiration, which can lead to changes in the local climate. It is a well-known fact that anthropogenic factors play a significant role in climate variability. Human activities, especially the emission of GHG, have led to a rise in global temperatures, which is one of the primary causes of climate change. As such, it is important to reduce GHG emissions and adopt sustainable agricultural practices to mitigate the effects of climate variability and ensure food and water security for future generations.

In addition to land resources, agriculture is a major user of water. Over 200 million ha of arable land is under irrigation, utilizing 2.500 billion m3 of water annually, representing 75 % of freshwater resources withdrawn from aquifers, lakes and rivers by human activity. Irrigation sustains a large portion of the total food supply about 40 % in the case of cereals. Finally, significant quantities of chemical inputs are applied to achieve high yields in intensive production systems including about 100 million tons of nitrogen used annually, leading to significant regional pollution. As a result of these large-scale activities, agriculture is a significant contributor to land degradation and, in particular, a major emitter of greenhouse gases. It emits into the atmosphere 13-15 billion tons of CO₂ per year, about a third of the total from human activities. Overall, agriculture is responsible for 25 % of carbon dioxide (largely from deforestation), 50 % of methane (rice and enteric fermentation), and more than 75 % of N₂O (largely from fertilizer application) emitted annually by human activities. If emissions of greenhouse gases, including those from agriculture, are not controlled in the coming decades, continued growth of their atmospheric concentrations is projected to result in severe climate change throughout the 21^st Century. If “dangerous anthropogenic interference” with the climate system is to be avoided in coming decades and warming is to be limited to “acceptable” temperature increases, then stabilization of atmospheric concentrations must be achieved.

This alteration directly affects agro-hydrological resources in the Koutaba Municipality affecting livelihoods. In the study area, warmer periods (dry season) lead to the drying up of water bodies and increased wilting of some crops which are more dependent on water. Animals which also need water for their daily living are affected leading to transhumance, and at some point, create farmer-grazer conflicts which further makes the climate variability issue complex. During the wet seasons, the rains much, leading to floods that destroy crops and also pollute sources of water therefore threatening a basic need for clean water and sanitation. The continuous alteration in climates has affected the production of food and brought in water and food insecurities. Climate change due to an “enhanced greenhouse effect” has the potential to change precipitation form, amount, timing, distribution, intensity and duration, and extremes.

The multiple effects of climate variability in the study area have also resulted in significant sinking in livelihoods. This effect has led to out-migrations as a result of poor yields and to an extent deaths (through suicide). This study seeks to find out the effects of climate variability on agricultural productivity, and how the impact has led to the alteration of the hydrological cycle and changes in water availability and recorded a toll or effects on the livelihood of people who are directly dependent on water resources (farmer). Floods which occurred in 2018 in Koutaba brought on by climate variability fostered by human activities made it harder to produce food. As a result, the price of food increases, and access becomes more and more limited, putting many at higher risk of hunger. Undernutrition is the largest health impact of climate change in the 21^st Century.

1.3 Research Questions

The main research question of the study is, what is the agro hydrological effect of climate variability on livelihoods in the Koutaba and how has this affected the livelihoods in Koutaba? Based on this question, the following specific research questions were formulated:

1. What is the magnitude of climatic variability in the Koutaba?
2. What are the agro-hydrological effects of climate variability in the Koutaba and how have livelihoods been affected by it?
3. How do the inhabitants adapt to the effects of climate variability on agro-hydrological resources in Koutaba?

1.4 Research Objectives

The main objective of the study is to examine the agro-hydrological effects of climate variability on livelihoods and how inhabitants are adapting to the effects of climate variations on agro-hydrological resources in Koutaba. Based on this objective, the following specific objectives were formulated:

1. To assess the magnitude of climate variability in Koutaba.
2. To examine the effects of climate variability on agro-hydrological resources in the Koutaba and how livelihoods have been affected.
3. To evaluate the adaptive strategies of inhabitants put in place to cope with the effects of climate variability on livelihoods.

1.5 Research Hypotheses

The main hypothesis for this study is, that climate variability is a threat to the management of agro-hydrological resources in Koutaba and is guided by the following specific hypotheses:

• Climate variability in Koutaba is driven more by anthropogenic than natural factors
• Climate variability has a negative relationship with agro-hydrological resources in Koutaba.
• The adaptation strategies put in place to cope with the effects of climate variability on livelihoods are not efficient in reducing the impact of climate variability on agro-hydrological resources.