Effects of urbanization and nonrenewable energy on carbon emission in Africa

This study investigates the impact of urbanization and nonrenewable energy consumption on carbon emissions. The context of the analysis is 54 African Union countries from 1996 to 2019. For estimation, we use panel quantile regression (PQR) and fully modified ordinary least squares (FMOLS). Our regression results demonstrate that there is a positive correlation between urbanization and CO₂ emission. Further, our empirical results confirmed that nonrenewable energy consumption increases environmental pollution in African Union countries. The outcomes demonstrate the EKC hypothesis because at the initial stage of development, when economic growth increases, environmental pollution increases; after a threshold point, environmental pollution decreases as economic growth increases. It can find an inverted U-shaped relationship between economic growth and CO₂ emission. The findings also show that urbanization should be planned; otherwise, it can lead to environmental degradation in the long run. Africa continent takes strict action and builds a blueprint for efficient and effective energy production and consumption. The only solution to achieve green growth in Africa is to shift from fossil fuel energy supply to renewable energy supply.

     

Comparative analysis of the growth impact of pollution and energy use in selected West African nations

We adopt the FMOLS and Granger causality technique to analyse the effect of energy use and carbon emissions on output growth in selected West African economies, which includes Nigeria, Gambia and Ghana, from 1970 to 2019. Findings confirm that energy use enhances growth in the three selected West African economies. But in terms of significance, energy consumption is significant in Nigeria and Gambia at a 1% level of significance while it is insignificant for the Gambia. CO₂ emission positively and significantly propels economic growth for the three selected West African economies. For Nigeria, causality evidence shows no direct influence among the variables. For Ghana, we find a bi-causal association between output growth and carbon emissions and a unidirectional causality from pollution to energy consumption. For Gambia, economic growth causes CO₂ emissions. We recommend that the West African government reinforce their stand on a sustainable growth path through energy conservation.

     

A methodology for the quantification of the net African dust load in air quality monitoring networks

This paper proposes and validates a methodology for the quantification of the daily African PM load during dust outbreaks in southern Europe. The daily net dust load in PM10 attributable to an African episode in a given region can be obtained by subtracting the daily regional background (RB) level from the PM10 concentration value at an RB station. As demonstrated in this paper, the daily RB level can be obtained by applying a monthly moving 30th percentile to the PM10 time series at an RB station after a prior extraction of the data of the days with African dust transport. The daily PM10 RB levels obtained can be subtracted from the daily PM10 levels recorded at the same RB site only on days when the occurrence of African dust outbreaks was demonstrated, the difference being the daily net African dust load. It is thus possible to quantify the African dust contribution during an African PM event in southern Europe without the need for PM speciation.The validation of this methodology was performed by comparing the estimated net dust load during African dust outbreaks at three RB stations and the crustal load determined by chemical speciation of PM10 filters. The correlation (r²>0.6) and the equivalence (correlation lines’ slopes ∼1) were significant in the three cases.     

COVID-19: From health crises to food security anxiety and policy implications

Like the rest of the world, African countries are reeling from the health, economic and social effects of COVID-19. The continent’s governments have responded by imposing rigorous lockdowns to limit the spread of the virus. The various lockdown measures are undermining food security, because stay at home orders have among others, threatened food production for a continent that relies heavily on agriculture as the bedrock of the economy. This article draws on quantitative data collected by the GeoPoll, and, from these data, assesses the effect of concern about the local spread and economic impact of COVID-19 on food worries. Qualitative data comprising 12 countries south of the Sahara reveal that lockdowns have created anxiety over food security as a health, economic and human rights/well-being issue. By applying a probit model, we find that concern about the local spread of COVID-19 and economic impact of the virus increases the probability of food worries. Governments have responded with various efforts to support the neediest. By evaluating the various policies rolled out we advocate for a feminist economics approach that necessitates greater use of data analytics to predict the likely impacts of intended regulatory relief responses during the recovery process and post-COVID-19.     

Balancing Water Resources Development and Environmental Sustainability in Africa: A Review of Recent Research Findings and Applications

Sustainable development in Africa is dependent on increasing use of the continent’s water resources without significantly degrading ecosystem services that are also fundamental to human wellbeing. This is particularly challenging in Africa because of high spatial and temporal variability in the availability of water resources and limited amounts of total water availability across expansive semi-arid portions of the continent. The challenge is compounded by ambitious targets for increased water use and a rush of international funding to finance development activities. Balancing development with environmental sustainability requires (i) understanding the boundary conditions imposed by the continent’s climate and hydrology today and into the future, (ii) estimating the magnitude and spatial distribution of water use needed to meet development goals, and (iii) understanding the environmental water requirements of affected ecosystems, their current status and potential consequences of increased water use. This article reviews recent advancements in each of these topics and highlights innovative approaches and tools available to support sustainable development. While much remains to be learned, scientific understanding and technology should not be viewed as impediments to sustainable development on the continent.     

Impact of the tropical storm Delta on the gross alpha,gross beta, 90Sr, 210Pb, 7Be, 40K and 137Cs activities measured in atmospheric aerosol and water samples collected in Tenerife (Canary Islands)

On 28 and 29 November 2005, the tropical storm Delta struck the Canary Islands (Spain) and the western shores of Morocco. Gravimetric and radiometric measurements carried out in atmospheric aerosol and water samples, collected after the storm, showed increased levels of total suspended particles (TSP) in the atmosphere and gross alpha, gross beta as well as ⁹⁰Sr activities in both the atmosphere and drinking water. These variations were most likely produced by local re-suspension of soil material. However, ²¹⁰Pb and ⁷Be activities, measured in atmospheric aerosols, did not increase until a week after the storm had passed. ⁴⁰K and ¹³⁷Cs activities, also measured in atmospheric aerosols, did not vary significantly with respect to previous weeks indicating that the slightly higher levels of TSP, measured during the week when the storm occurred, were not produced by the long-range transport of re-suspended aerosols from the African continent, as it has been observed in other occasions at this site. Gross alpha, gross beta, ⁴⁰K and ⁹⁰Sr levels in drinking water samples increased after the storm over their average values by approximately 245%, 245%, 130% and 440%, respectively. These results indicate how important the local re-suspension and later deposition/scavenging of aerosols may be on the water supply in Tenerife.     

Assessing decadal changes in rainwater alkalinity at a rural Mediterranean site in the Montseny Mountains (NE Spain)

Annual volume-weighted mean (VWM) concentrations in rainwater collected at La Castanya (LC, Montseny Mountains, NE Spain) were analysed from 1983 to 2000 to study the temporal trends in precipitation chemistry, and the causes behind the changes. A significant positive correlation was found between annual rainwater SO₄²⁻ concentrations at LC and Spanish SO₂ emissions (r=0.73, P=0.0008) both decreasing remarkably during this period. Rainwater alkalinity increased during the period, shifting from negative values at the beginning (VWM in the 5 initial years=−2.7 μeq l⁻¹) to alkaline values in recent years (VWM in the 5 final years=18.0 μeq l⁻¹). Stepwise regression analysis indicated that 88% of the variation of alkalinity could be accounted for by the variability of non-marine Ca²⁺ and non-marine SO₄²⁻, with a more prominent dependence on Ca²⁺.Rains of African provenance were highly enriched in alkalinity and Ca²⁺, but no significant increases in their occurrence were found for the study period. Because of the reported higher dust updraft in northern Africa during years of high North Atlantic Oscillation (NAO) index, we also explored the relationship between rainwater variables associated with an African provenance and NAO. Annual precipitation was inversely related to NAO (r=−0.61, P=0.007). The annual wet deposition of African dust-related elements showed no correlation with NAO, probably because wet deposition of these elements depends on two factors (precipitation and dust updraft) which have opposite behaviour with respect to NAO. We hypothesise that dry deposition of African dust during dry spells (not sampled in this study) might be higher during high NAO-index years.     

The effects of air pollution on human mortality: does gender difference matter in African countries?

The relationship between environmental factors and human health has long been a concern among academic researchers. We use two indicators of environmental pollution, namely particulate matter (PM₁₀) and carbon dioxide (CO₂) to examine the effects of poor air quality on human mortality. This study explores an issue that has largely been ignored, particularly in the African literature, where the effect of air pollution on human mortality could be influenced by gender specification. We analyse a panel data from 35 African countries and our result suggests that the elevated levels of PM₁₀ and CO₂ have a significant effect on the increasing mortality rates in infants, under-five children and adults. Although the effect of poor air quality on adults is found to differ between genders, such difference is not statistically significant. We conclude that the air pollution effects, on average, are similar between genders in the African countries.     

Airborne desert dust and aeromicrobiology over the Turkish Mediterranean coastline

Between 18 March and 27 October 2002, 220 air samples were collected on 209 of 224 calendar days, on top of a coastal atmospheric research tower in Erdemli, Turkey. The volume of air filtered for each sample was 340 liters. Two hundred fifty-seven bacterial and 2598 fungal colony forming units (CFU) were enumerated from the samples using a low-nutrient agar. Ground-based dust measurements demonstrated that the region is routinely impacted by dust generated regionally and from North Africa and that the highest combined percent recovery of total CFU and African dust deposition occurred in the month of April (93.4% of CFU recovery and 91.1% of dust deposition occurred during African dust days versus no African dust present, for that month). A statistically significant correlation was observed (peak regional African dust months of March, April and May; r_s=0.576, P=0.000) between an increase in the prevalence of microorganisms recovered from atmospheric samples on dust days (regional and African as determined by ground-based dust measurements), versus that observed on non-dust days. Given the prevalence of atmospherically suspended desert dust and microorganisms observed in this study, and that culture-based studies typically only recover a small fraction (<1.0%) of the actual microbial population in any given environment, dust-borne microorganisms and other associated constituents (organic detritus, toxins, etc.) may play a significant role in the regional human and ecosystem health.     

The negative impacts of human activities in the eastern African region: an international waters perspective

The complex interactions between human activities and the environment at the interface of land and water is analyzed with a focus on the Somali Current (East Africa), and Indian Ocean Island States, subregions of the Global International Waters Assessment (GIWA). These 2 subregions contain some of the world's richest ecosystems, including the high biodiversity forests of Madagascar and the diverse coastal habitats of the eastern African coast. These ecosystems support local communities and national and regional economies. Current and future degradation of these systems, from water basins to continental shelves, affects the livelihoods and sustainability of the countries in the region, and long-term efforts to reduce poverty. The assessments determined that pollution and climate change are the primary environmental and social concerns in the Islands of the Indian Ocean, while freshwater shortage and unsustainable exploitation of fisheries and other living resources are the primary environmental and social concerns in East Africa. The GIWA approach, through assessing root causes of environmental concerns, enables the development of policy approaches for mitigating environmental degradation. This paper explores policy frameworks for mitigating the impacts, and reducing the drivers, of 3 environmental concerns--freshwater shortage; solid waste pollution; and climate change--addressing social and institutional causes and effects, and linking the subregions to broad international frameworks. The common theme in all 3 case studies is the need to develop integrated ecosystem and international waters policies, and mechanisms to manage conflicting interests and to limit threats to natural processes.     

Atmospheric polycyclic aromatic hydrocarbons in remote European and Atlantic sites located above the boundary mixing layer

Background, aim and scope  

Ambient air concentrations of polycyclic aromatic hydrocarbons (PAH) were determined at five elevated mountain sites on the European continent and the Atlantic Ocean. All sites can be considered remote background areas since they are situated above the timberline and they lack local emission sources of these compounds.     

Significant geographic gradients in particulate sulfate over Japan determined from multiple-site measurements and a chemical transport model: Impacts of transboundary pollution from the Asian continent

We found a significant geographic gradient (longitudinal and latitudinal) in the sulfate (SO₄^2?) concentrations measured at multiple sites over the East Asian Pacific Rim region. Furthermore, the observed gradient was well reproduced by a regional chemical transport model. The observed and modeled SO₄^2? concentrations were higher at the sites closer to the Asian continent. The concentrations of SO₄^2? from China as calculated by the model also showed the fundamental features of the longitudinal/latitudinal gradient. The proportional contribution of Chinese SO₄^2? to the total in Japan throughout the year was above 50–70% in the control case, using data for Chinese sulfur dioxide (SO₂) emission from the Regional Emission Inventory in Asia (40–60% in the low Chinese emissions case, using Chinese SO₂ emissions data from the State Environmental Protection Administration of China), with a winter maximum of approximately 65–80%, although the actual concentrations of SO₄^2? from China were highest in summer. The multiple-site measurements and the model analysis strongly suggest that the SO₄^2? concentrations in Japan were influenced by the outflow from the Asian continent, and this influence was greatest in the areas closer to the Asian continent. In contrast, we found no longitudinal/latitudinal gradient in SO₂ concentrations; instead SO₂ concentrations were significantly correlated with local SO₂ emissions. Our results show that large amounts of particulate sulfate are transported over long distances from the East Asian Pacific Rim region, and consequently the SO₄^2? concentrations in Japan are controlled by the transboundary outflow from the Asian continent.     

Organochlorine contaminants in cormorant, darter, egret, and ibis eggs from South Africa

During the last 15 years, no research has been published on the levels of pesticides in bird eggs from South Africa, despite the high levels found previously. We analysed eggs from African darter, cattle egret, reed cormorant, African sacred ibis, as well as single eggs from some other species, and found HCB, DDTs, HCHs, chlordanes and PCBs at detectable levels. The presence of mirex in all species was unexpected, since this compound was never registered in South Africa. It also seemed as if terrestrial feeding birds had higher DDE:PCB ratios when compared with aquatic feeding birds. Except for chlordane, the African darter eggs had the highest levels of all other compounds (mean 370 and 300 ng g(-1) ww Sigma pesticides and Sigma PCBs, respectively). Multivariate analysis clearly distinguished the aquatic and terrestrially feeding birds on pollution profile. The African darter (aquatic feeding) and the cattle egret (terrestrial feeding) would be good indicator candidates. Eggshell thinning was detected in the African darter, and was associated with most of the compounds, including DDE and PCBs. We raise a concern that generally longer living birds in warmer climates, laying fewer eggs per clutch, might be at increased risk when compared with trophically similar birds exposed to equivalent levels of pollution in colder climates. Given the scarcity of water and the high biodiversity in Southern Africa, climate change will exert strong pressure, and any additional anthropogenic contamination at levels that can cause subtle behavioural, developmental and reproductive changes, can have serious effects.     

Prevalence and drivers of poison use by South African commercial farmers and perceptions of alternative livestock protection measures

The use of poison to eliminate predators is causing African vulture populations to collapse. To understand the prevalence and motivations of this practice we conducted an extensive survey with South African commercial farmers. Using a specialised questioning technique and ad hoc quantitative methods we found that an estimated 22% and 31% of farmers used poison over a 1-year and 5-year period, respectively. Poison use hotspots generally coincided with small stock farming areas. The strongest predictor of poison use was whether farmers believed the practice to be common amongst their peers. Our results suggest that farmers’ attitudes to vultures are primarily positive, and farmers are less likely to use poisons if they frequently encounter vultures on their farm. Overall, our findings provide an understanding on poison use that provides leverage points to change farmers’ behaviour and help avert the African vulture crisis and possible cascading ecosystem impacts.Supplementary informationThe online version of this article (10.1007/s13280-020-01461-2) contains supplementary material, which is available to authorized users.     

Scientists’ warning to humanity on the freshwater biodiversity crisis

Freshwater ecosystems provide irreplaceable services for both nature and society. The quality and quantity of freshwater affect biogeochemical processes and ecological dynamics that determine biodiversity, ecosystem productivity, and human health and welfare at local, regional and global scales. Freshwater ecosystems and their associated riparian habitats are amongst the most biologically diverse on Earth, and have inestimable economic, health, cultural, scientific and educational values. Yet human impacts to lakes, rivers, streams, wetlands and groundwater are dramatically reducing biodiversity and robbing critical natural resources and services from current and future generations. Freshwater biodiversity is declining rapidly on every continent and in every major river basin on Earth, and this degradation is occurring more rapidly than in terrestrial ecosystems. Currently, about one third of all global freshwater discharges pass through human agricultural, industrial or urban infrastructure. About one fifth of the Earth’s arable land is now already equipped for irrigation, including all the most productive lands, and this proportion is projected to surpass one third by midcentury to feed the rapidly expanding populations of humans and commensal species, especially poultry and ruminant livestock. Less than one fifth of the world’s preindustrial freshwater wetlands remain, and this proportion is projected to decline to under one tenth by midcentury, with imminent threats from water transfer megaprojects in Brazil and India, and coastal wetland drainage megaprojects in China. The Living Planet Index for freshwater vertebrate populations has declined to just one third that of 1970, and is projected to sink below one fifth by midcentury. A linear model of global economic expansion yields the chilling prediction that human utilization of critical freshwater resources will approach one half of the Earth’s total capacity by midcentury. Although the magnitude and growth of the human freshwater footprint are greater than is generally understood by policy makers, the news media, or the general public, slowing and reversing dramatic losses of freshwater species and ecosystems is still possible. We recommend a set of urgent policy actions that promote clean water, conserve watershed services, and restore freshwater ecosystems and their vital services. Effective management of freshwater resources and ecosystems must be ranked amongst humanity’s highest priorities.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01318-8) contains supplementary material, which is available to authorized users.     

Decabromodiphenyl ethane and decabromodiphenyl ether in Swedish background air

Decabromodiphenyl ethane (DPDPE) is a flame retardant that has been on the market for more than 20 years and is used as a replacement for decabromodiphenyl ether (BDE-209). Environmental data on DPDPE are scarce but for BDE-209, studies have shown that long-range transport in the atmosphere leads to contamination of remote regions. Given their similar physical-chemical properties, we hypothesized that this is also true for DPDPE. In this study we explored the European continent as a source for DBDPE by collecting air samples at a back-ground location in southern Sweden. Twelve samples with stable air mass back trajectories over the 24 h sampling period were analysed. BDE-209 and 5 polycyclic aromatic hydrocarbons (PAHs) were also included in the study. The concentration ranges of DBDPE and BDE-209 were similar, 0.077-7.9 and 0.093-1.8 pg m⁻³ air, respectively. The highest concentrations were detected when the air originated from the European continent and the lowest during periods with rather stagnant air over southern Scandinavia. The concentrations of DBDPE and BDE-209 did not co-vary, indicating that there are different major sources of the two compounds. In air, the compounds measured in this study are predominantly associated with particles. PAHs in the atmosphere are known to originate primarily from combustion processes and their concentrations were highly correlated with several measures of atmospheric particle concentration, i.e. PM 10, PM 2.5, soot, and N 450 (number of particles in the size range approximately 420-450 nm). No clear correlations were found between the concentrations of DBDPE or BDE-209 and any of the measures of particle concentrations, indicating that the emissions of these are not related to the major sources of emissions of soot or small particles.     

Impact of the Saharan dust outbreaks on the ambient levels of total suspended particles (TSP) in the marine boundary layer (MBL) of the Subtropical Eastern North Atlantic Ocean

Six years (1998–2003) of measurements of ambient air concentrations of total suspended particulate (TSP) measured at a rural background monitoring station in Tenerife (Canary Islands), the El Río station (ER, 28°08′35″N, 16°39′20″W, 500 m a.s.l.) were studied. African dust outbreaks were objectively identified using a new quantitative tool, called the African Index. This index indicates the percentage of time that an air mass remained over an African region at one of three possible height intervals of the lower troposphere. After identifying these episodes, a study of the background TSP levels at the ER station and of direct and indirect (those which cause vertical deposition of dust) African air mass intrusion impacts was performed. Taking into account both direct and indirect episodes, a total of 322 days of African dust intrusion were objectively identified (a mean of 54 episodes per year) in the period 1998–2003, some of them caused by “transition episodes” or “return African air masses”. A subjective method confirmed that 256 of these days were caused by direct impacts of African dust on the ER station. A mean TSP value of 21.6 μg m⁻³ was found at the station during this period. All the episodes occurred when the TSP concentration was >28.5 μg m⁻³. The TSP background (14 μg m⁻³) can be assumed to be representative of the MBL of the Eastern North Atlantic subtropical region. The highest number of dust gravitational settlement (or indirect) episodes occurs in summer, but the highest contribution of these episodes to the TSP levels is in March with a monthly mean TSP contribution of up to 30.5 μg m⁻³.     

C2–C8 NMHCs over the Eastern Mediterranean: Seasonal variation and impact on regional oxidation chemistry

More than 2500 measurements of C₂–C₈ non-methane hydrocarbons (NMHCs) have been conducted at Finokalia sampling station on the island of Crete over a thirty-month period (September 2003–February 2006), to investigate the factors controlling NMHC levels and estimate their role in the oxidizing capacity of the Eastern Mediterranean atmosphere. Atmospheric concentrations of NMHCs range from below the detection limit (5 pptv) to a few ppbv and present a hydroxyl radical (OH) driven seasonal pattern with lower values during summer. The diel variability was also influenced by the reaction of the NMHC with the OH radical, exhibiting a nighttime maximum and a midday or early afternoon minimum. Long-lived compounds demonstrate higher concentrations under the influence of the northern sector (European continent), indicating that besides chemistry, transport significantly contributes to NMHCs levels in the area. Based on the observed NMHCs diurnal cycles, mean OH radical levels of 3.5 × 10⁶ molecules cm⁻³ have been derived for May–October period.     

Dioxins (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-furans) in traditional clay products used during pregnancy

Geophagy, the practice of consuming clay or soil, is encountered among pregnant women in Africa, Eastern Asia and Latin America, but also in Western societies. However, certain types of clay are known to contain high concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The aim of this study was to determine the PCDD/F contents of orally consumed clays purchased from Dutch and African markets. Congener patterns were compared with those of pooled human milk samples collected in eight African countries, to investigate a possible relationship with clay consumption. From the Dutch market thirteen clay products were examined, seven of African and six of Suriname origin. From seven African countries, twenty clay products were collected. All 33 clay products were screened with a cell-based bioassay and those showing a high response were analyzed by GC/HRMS. High PCDD/F concentrations were measured in three clay products from the Dutch market, ranging from 66 to 103 pg TEQ g^-1, whereas clay products from African countries were from 24 to 75 pg TEQ g^-1. Patterns and relatively high concentrations of PCDD/Fs in human milk samples from the Democratic Republic of the Congo and Côte d’Ivoire suggest a relationship with the consumption of contaminated clay. Frequent use of PCDD/F contaminated clay products during pregnancy may result in increased exposure of the mother and subsequently the developing fetus and new-born child. The use of these contaminated clays during pregnancy should be carefully considered or even discouraged.     

African dust contributions to mean ambient PM10 mass-levels across the Mediterranean Basin

Data on mass-levels of PM₁₀ measured at regional background sites across the Mediterranean Basin, available from Airbase (European Environmental Agency) and from a few aerosol research sites, are compiled. PM₁₀ levels increase from north to south and west to east of the Basin. These variations are roughly coincident with the PM₁₀ African mineral dust load. However, when subtracting the African dust from mean PM₁₀ levels using a consistent methodology, the PM₁₀ background levels are still 5–10 μg m^?3 higher in the Eastern Basin (EMB) when compared with those in the Western (WMB), mainly due to the higher anthropogenic and sea spray loads.As regards for the seasonal trends, these are largely driven by the occurrence of African dust events, resulting in a spring-early summer maximum over the EMB, and a clear summer maximum in the WMB, although in this later region the recirculations of aged air masses play an important role. Furthermore, a marked seasonal trend is still evident when subtracting the African dust load. This is characterised by a high summer maximum (driven by low precipitation, high insolation) and a winter minimum (intense synoptic winds).Important inter-annual variations in the dust contribution are detected, more evident in the southern sites. These differences are generally associated with the occurrence of extreme dust events. Generally, the years with higher dust contributions over the EMB correspond with lower contributions over the WMB, and vice versa.The characterization of individual particles, collected in both basins during African dust events, by scanning electron microscopy reveals only slight differences between them. This fact probably reflects the high degree of mixture of mineral dust from different sources before the transport towards the receptor sites.