Climate variability and its implication for water resources and livelihoods in Uganda

Abstract

This thesis examines the climatic trends of rainfall and temperature in Uganda using historical data. And because climate is an important aspect in water resources management and livelihoods formation, an attempt to explain how the interaction impacts on the two is made in the context of climate variability and change. The assumption is that climate change/variability has had an effect on water resources management and the way individual, households and society at large form livelihoods in Uganda. The rationale for the investigation is the number of climate and livelihood related studies that have been undertaken for Uganda over recent years, which have not focused specifically on the water resources management and livelihood formation. The study is grounded by reviewing the theoretical perspectives of climate science which underpin the concepts of climate change, climate variability and impacts on livelihoods in the world, tropics, Africa, east Africa and Uganda in that order. A cross sectional research design based on selected case studies from sub-counties located in the main sub-basins across the country is used. Both qualitative and quantitative data analysis techniques are applied independently or in combination on climatic data from Uganda‟s Department of Meteorology, data generated from field interviews and landsat images. The data sets are analysed using MS EXCEL, SPSS, MATLAB, ANCLIM, TREND TOOL, GIS and ENVI 4.8 to establish climatic trends and deduce evidence of change and variability. The impact on livelihood formation is investigated through the assets available to the households using the DFID framework. The study therefore has investigated the characteristics of climate in Uganda especially by following up on the responses that arose from the field study. Through their own observations, respondents noticed changes in temperature and rainfall. Temperature variables like diurnal temperature range, maximum and minimum temperatures and rainfall (monthly, seasonal, annual) have been investigated, to establish whether these observations were impacting on livelihood formations and water resources which are central in the wellbeing of individual households. Results show decadal variability of rainfall with marked seasonal cycles, temporal variability of drought patterns is detected; variations in annual rainfall are low with no significant trends observed in the main drainage sub-basins. Significant trends occur in October, November, December and January. A noticeable decrease in the annual total rainfall was observed mostly in north-western and south-western sub-basins. Rainfall trend in the second normal of June-July-August (JJA) is decreasing in all the main drainage sub-basins; highest rainfall was recorded in April, while January, June and July have the lowest rainfall. Spatial analysis results show that stations close to Lake Victoria recorded high amounts of rainfall. Average annual coefficient of variability was 19% signifying low variability. Rainfall distribution is bi-modal with maximums experienced in March- April- May and September- October- November seasons of the year. PCI values show a moderate to seasonal rainfall distribution. FNW Nsubuga – University of Pretoria Page 11 Spectral analyses of the time components reveal the existence of a major period around 3, 6 and 10 years. Intra-annual temperature show reduced variability over recent decades, which is not statistically significant. Maximum temperatures are more variable compared to minimum temperatures in Uganda. An increasing trend in hot days, hot nights, warm nights and warm spells are also detected. At seven of the stations, annual temperature range and diurnal temperature range trends are negative. The finding that intra-annual and intra-monthly variance is declining suggests that fewer anomalously extreme temperature episodes occur. The gap between maximum and minimum extremes is reducing, which supports the observation that minimum temperatures are on the increase. At a micro-level analysis using Namulonge as a case study, total rainfall in March-May season decreased, while maximum temperatures increased between April and September, with statistically significant trends at 5% confidence level. The Mann-Kendall test revealed that the number of wet days reduced significantly. Temperatures are warmer and rainfall higher in the first climate normal compared to the recent 30 years. Direct rainfall, which is the most important source of water for water resources, recently, is experiencing variability, which is threatening the distribution of water resources in Uganda. The characteristics, availability, demand and importance of present day water resources in Uganda as well as the various issues, and challenges pertaining to management of water resources of the country are established. The present analysis reveals that surface-water area fluctuation is linked to rainfall variability. In particular, Lake Kyoga basin lakes experienced an increase in surface-water area in 2010 compared to 1986. This work has important implications to water resources management and people whose livelihoods depend on natural resources especially in this era of climate change. Evidence from the field survey validates what data analysis reveals from historical data. Respondents from the field study are aware of climate change, had noticed some changes in climatic variables and were adapting by changing lifestyle and diversifying to activities that are less prone to weather. Livelihoods in Uganda have evolved based on the availability of opportunity afforded by the natural resources base including water resources.