Droughts in the Sudano-Sahelian Ecological Zone of Nigeria: Implications for Agriculture and Water Resources Development

This study evaluates the extent and degree of severity of droughts in the Sudano- Sahelian Ecological Zone of Nigeria using rainfall data spanning a period of 60 years 1949- 2008 for eight meteorological stations in the zone The Normalized Rainfall Index was used in depicting periods of different drought intensities in the region The results revealed that the zone was characterized by larger extent of severe drought since the beginning of 1968 through the early 1970s and then the 1980s in which the drought was so severe than any other decade in the study period The late 1990s and the 2000s on the other hand have been witnessing a decrease in the number of drought occurrences in the zone The mean absolute probability of mild moderate and severe droughts for the zone was 0 13 recurrence interval of 7 7 years 0 11 recurrence interval of 9 1 years and 0 08 recurrence interval of 12 5 years respectivel

A Review of Air Quality and Concentrations of Air Pollutants in Nigeria

This study generally classifies air pollutants on the basis of: primary or secondary, natural or anthropogenic, chemical composition, physical state, and the space scales of their effects. Air pollutants that affect air quality in Nigeria were discussed based on natural and anthropogenic sources. The natural sources include: sand dust, sea spray, volcanic activities, smoke and carbon monoxide from wildfires among others, while the anthropogenic sources include: vehicular emissions, mining activities, industries such as cement companies and quarry factories, agricultural practices and solid waste dumps among others. Some of the atmospheric pollutants that posed greatest threat to human health were equally examined. They include: Sulphur dioxide (SO2) which can react with water vapor (H2O) in the atmosphere to form sulphuric acid (H2SO4) and thus acid rain; particulate matter (PM) with less than 10 μm, particularly fine particles (PM2.5 ) and particles in the fine fraction that are smaller than 0.1 μm (ultrafine particles), can carry toxic chemicals which are linked to cancer; carbon monoxide (CO), even in very small concentrations, can prevent oxygen from being delivered through the body major organs; ozone which is a highly reactive gas causes oxidation of a number of macromolecules within a biological system and produces free radicals that can damage DNA molecules and cause carcinogenesis. Based on the aforementioned, this study recommends that priority should be given to the establishment of air monitoring stations in all urban centers of the country in order to provide accurate and continuous information on air quality. Keywords: anthropogenic pollutants, atmosphere, particulate matter, pollutio

IS THE CHANGING RAINFALL PATTERNS OF KANO STATE AND ITS ADVERSE IMPACTS AN INDICATION OF CLIMATE CHANGE?

Annual and monthly rainfall data for Kano from the period 1911 to 2010 (100 years) were used in this study to determine the changing patterns of rainfall and its adverse impacts on transport infrastructures. The Relative Seasonality Index of the rainfall series revealed that the rainfall is in 3 months or less. In order to identify trends, the rainfall series was divided into 10-year non-overlapping and 30-year overlapping sub-periods and the Cramer’s test was then used to compare the means of the sub-periods with the mean of the whole record period. The results of the 10-year nonoverlapping sub-period analysis revealed a recent increase in the annual rainfall series in the last two sub-periods (1991-2000 and 2001-2010). The results of the 30-year overlapping sub-periods analysis also revealed that the recent sub-period, 1981-2010, was significantly wetter than the long-term conditions. Findings revealed that the increase in annual rainfall amount in recent years is as a result of the increased in June, July and August rainfalls. This may be responsible for the frequent occurrences of floods in the months of July and August which is an indication of climate change. The 10-year running mean shows that the increasing yield of the annual rainfall started from the mid 1990s to the end of the study period. The major implication of this increased in amount and intensity of rainfall on transport infrastructures is that models built on the perceived decreasing rainfall, such as drainages, bridges, etc, have to be reviewed. It is recommended that planning and designing of transport infrastructures should take into account the recent increasing nature of rainfall

Impacts of climate change and adaptation strategies in rural communities of Kaduna State, Nigeria

This study focused on the impacts of climate change on the livelihoods of some selected rural communities of Kaduna state, and the adaptation strategies employed by the people to ameliorate the scourge of climate change. Data for this study were obtained from a direct field study based on the result of 426 questionnaires that were administered to household heads. Descriptive statistics was used to describe the socioeconomic characteristics of the respondents. A five point Likert scale was used to determine the impacts of climate change and adaptation strategies employed by the rural communities. Focus Group Discussions were also held in each Local Government Area in order to obtain in-depth information on the changing climate. The study identified decline in crop yields with a mean score (x̄) of 4.01, increased sickness (x̄ = 3.85), decrease in soil fertility (x̄ = 3.83), decline in forest resources (x̄ = 3.66) as the most significant impacts of climate change in the area; whereas use of fertilizer/animals dung (x̄ = 3.89), water harvesting (x̄ = 3.68), planting of economic trees and drought resistant crops (x̄ = 3.25) among others were the most significant and sustainable adaptation strategies adopted by the rural people. The study recommended that awareness programs on climate change challenges should be intensified, and probabilistic analysis of observed rainfall data in order to provide information about the beginning, the end and length of the rainy season, and the amount of available water during the season. Lastly, sustainable adaptation strategies employed by the rural people should be strengthened.Keywords: Adaptation, climate change, impacts, livelihood, resources, rural communitie

Rainfall variability and drought characteristics in two agro-climatic zones: An assessment of climate change challenges in Africa

This paper aims at examining drought characteristics as an evidence of climate change in two agro-climatic zones of Nigeria and farmers' perceptions of impacts and adaptation strategies. The results show high spatial and temporal rainfall variability for the stations, in consequence, there are several anomalies in rainfall in recent years but much more in the locations around the Guinea savanna. The inter-station and seasonality statistics reveal less variable and wetter early growing seasons and late growing seasons in the Rainforest zone, and more variable and drier growing seasons in other stations. The probability (p) of dry spells exceeding 3, 5 and 10 consecutive days is very high with 0.62≤p≥0.8 in all the stations, though, the p-values for 10day spells drop below 0.6 in Ibadan and Osogbo. The results further show that rainfall is much more reliable from the month of May until July with the coefficient of variance for rainy days 0.30), though CV-RD appears higher in the month of August for all the stations. It is apparent that farmers' perceptions of drought fundamentally mirror climatic patterns from historical weather data. The study concludes that the adaptation facilities and equipment, hybrids of crops and animals are to be provided at a subsidized price by the government, for farmers to cope with the current condition of climate change

Hydrogeomorphic Characteristics of Urban Flood Triggers in Gombe Town, Nigeria as Monitored in 2014

Urban flooding has become a monumental yearly disaster in many of the world’s cities and Gombe town in particular. This paper focused on some hydro-geomorphological characteristics that influence flooding in Gombe town. Statistical methods and geographic information techniques were used for the assessment. The result revealed that the highest API of 166.62 mm occurred on the 5/9/2014. The rainfall amount was 92.5mm for a duration 48 minutes, average rainfall intensity was 115.63, stage height (1.42m), average flow velocity (0.98m/s), and instantaneous discharge of 9.47m3 /s. This corresponds with the flood disaster that occurred in Gombe town on the same date (5/9/2014). On the other hand, the least API of 18.12 mm occurred on the 18/6/2014. The rainfall amount was 1.2mm for 62 minutes, average rainfall intensity was 1.16, stage height (0.30m), average flow velocity (0.24m/s), and instantaneous discharge of 0.49m3 /s. findings also showed that very steep slope covered 2.4537km2 (1.78%), steep slope covered 3.60235km2 (2.61%), moderate slope (0.735574km2 or 0.53%), gentle slope (131.106km2 or 94.89%) and flat areas (0.259854km2 or 0.19%). The study recommended flood resilience technology, provision of adequate urban drainages and proper storm water management.Keywords: Drainage density, flow accumulation, rainfall, urban floodin

Meteorological Drought and Temperature in Sudano-Sahelian Region of Nigeria under Increasing Global Warming

This study examinesmeteorological drought and temperature in the Sudano-Sahelian region of Nigeria under increasing global warming. Rainfall data of 60 years (1961 to 2020) and temperature of 40 years (1981–2020) for nine stations were used to quantify drought occurrences as well as the pattern of temperature. The Bhalme and Mooley Drought Index (BMDI) and Student’s t-test were used to indicate if changes have occurred in the amount of rainfall and temperature (increase or decrease) over space and time in the study region. The BMDI was used because it is simple and able to depict historically documented droughts better than other indices. The student’s t-test was used to determine if the sub-period means of the series have altered significantly over time. Results show that the spatial and temporal occurrence and duration varied from one sub-area to another. Also, its intensity was mainly from mild to moderate. Results also show a consistent alternation between drought and wet years over the study period. The trend of temperature shows a tendency towards decreasing temperature during the period of study although it was not significant. The study concludes that the study region experiences climate variability that may well be part of global climate change

La gestion durable des eaux pluviales urbaines par la gestion de l\u27espace et la subsidiarité. Le cas d\u27Addis Abeba (Ethiopie)

La ville d\u27Addis Abéba se trouve de plus en plus confrontée aux problèmes de gestion des eaux pluviales avec des conséquences parfois dramatiques sur les citadins et leur patrimoine ainsi que sur l\u27environnement. Bien que la préoccupation s\u27exprime au travers des déclarations d\u27intention et de multiples projets d\u27urgence, le problème n\u27a pas eu l\u27occasion d\u27être abordé d\u27une manière intégrée, ni dans le cadre d\u27un document prévisionnel ni dans le cadre d\u27un travail de recherche. Nous constatons également une inadéquation entre l\u27effort mobilisé et l\u27amélioration souhaitée. Pour mieux comprendre les causes du dysfonctionnement du système existant de la gestion des eaux pluviales urbaines (SGEPU) et explorer les potentialités (socio-économiques, organisationnelles, etc.), l\u27analyse a d\u27abord porté sur la gestion de l\u27espace urbain en vue d\u27une gestion durable des eaux pluviales. Ainsi, les différentes typologies urbaines ont été définies (dense structurée, dense non structurée, moins dense, etc.). Pour chacune d\u27entre elles les problèmes types et leurs causes ont été identifiés. Les facteurs extrinsèques du dysfonctionnement ont été également mis en évidence à l\u27aide d\u27une analyse systémique. Après avoir saisi le contexte général, une analyse détaillée du SGEPU est menée pour aborder les diverses dimensions du système : phénomènes à gérer, état du réseau et des cours d\u27eau, impacts et enjeux, vécu et perçu de la population, organisation, performance et pérennité des divers acteurs, politique adoptée, pratiques populaires, etc. Cette analyse fournit, entre autres, une connaissance typologique de l\u27état de l\u27équipement et de son fonctionnement ainsi que le souhait de la population en termes d\u27organisation et de contribution. Parmi les éléments de réponse proposés, un outil organisationnel est élaboré pour cadrer et rendre durable (en pérennité et en pertinence) le drainage urbain notamment au niveau local (quartier). Des éléments de réponse généraux portant sur les mesures techniques et urbanistiques sont également abordés. Ceux-ci focalisent notamment sur une conception intégrée des ouvrages d\u27assainissement et des cours d\u27eau dans l\u27espace urbain