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Africa's population is expected to triple by 2050, owing to rapid urbanisation and overall demographic trends. The combined pressures of urbanisation and climate change impact the ecosystem and the services it provides. As a result, additional dangers such as increased flooding, and environmental disruption have risen. Therefore, devising adaptive solutions to mitigate flood risk impacts while also building community resilience is needed. Evidence suggests that Nature‐based Solutions (NbS) can potentially alleviate floods and mitigate climate change impacts while also delivering other societal benefits. Despite rising NbS popularity following its recognition in the last decade, studies on its recognition in Africa remain limited. For this reason, this paper reviewed NbS studies conducted in East Africa (EA) to evaluate opportunities and barriers surrounding NbS adoption in EA. Academic literature published from January 2012 to May 2022 was reviewed using a comprehensive search of the SCOPUS database. Results show 14 papers have been published during the period, with the majority being post‐2020. In addition, the majority of the articles focused on cities and peri‐urban settlements, while public awareness, clear guidelines on performance monitoring, stakeholder inclusion, and diverse demonstration projects were highlighted as potential success factors for the adoption of NbS in EA. [ABSTRACT FROM AUTHOR]

The paper reflects on the lessons from two case studies in order to discuss (1) how they address Ostrom's eight principles and (2) implications for social, economic and environmental challenges. The two case studies are of forest communities in Venda in South Africa and Ciptagelar, West Java, discussed in terms of their social, environmental and economic approaches. In both cases, the communities see themselves as related to nature; in the case of Venda, they express this as a totemic relationship and have been inspired to apply an ecological calendar that was taught to them during the time Mphatheleni Makaulule spent learning from Amazonian leaders. In the case of Ciptagelar, the nomadic way of life is based on a sense of being stewards who do not commodify rice, a sacred source of life, which is in turn dependent upon all the co‐existent creatures and ultimately the forest, which is their home. In both communities, the environment and people are priorities managed by observing the natural cycle. In both communities, an ecological calendar guides the planning and harvesting of crops. In Tshidzivhe Venda, a rigorous approach to crops, harvesting from the forest and re‐planting the forest, is observed, and the entire community act as caretakers and are required to ask permission before harvesting from the forest. In Ciptagelar, West Java, the chief reads the signs when it is time to move to another area and follows a careful approach to biodiversity ensuring that paddy is grown only for certain months so that other creatures can thrive in other months. The Balancing Individualism and Collectivism Special Integration Group has focused on learning by doing using an applied mixed methods approach. It is based on a community of practice spanning NGOs, community projects and university departments. It is supported by a small NRF fund, some funding from UNISA and in kind support from participants. We work together because of shared values and mutual respect. [ABSTRACT FROM AUTHOR]

Southern Africa harbors exceptional biodiversity that is increasingly threatened by climate change, land use, and other pressures. However, risks to the regional ecosystems and quality and consistency of adaptation strategies remain understudied, making conservation and restoration efforts challenging. Here, we reviewed scientific articles published during the period 2000–2020, which (1) addressed observed and projected impacts of climate change on different species, populations, and ecosystems in nine southern African countries, and (2) formulated management and policy responses aiming to mitigate these impacts. We identified and evaluated 28 papers meeting these search criteria. We found that the three components of our investigation, that is, ecosystem type, type of impact, and management and policy responses, were covered by research rather fragmentarily. However, the reviewed publications addressed a large variety of species and ecosystems and a variety of processes, from local extinction, range contraction, and increased mortality to modified inter‐specific interactions. The identified human responses included active vegetation and animal management, improved conservation policies, and monitoring. Most of the publications highlighted severe data limitations, lacking coordination of conservation policies, and insufficient consideration of transient environmental conditions in management and policy planning. We conclude that the current level of understanding of climatic threats to species and ecosystems is limited in southern Africa, and new coordinated research and monitoring actions are needed. This review characterized the high diversity of climate change risks to ecosystems and related social responses, potentially helping to attract further research attention and inform regional adaptation strategies. [ABSTRACT FROM AUTHOR]

BACKGROUND: The southern armyworm (SAW) Spodoptera eridania (Stoll) (Lepidoptera: Noctuidae) is native to the tropical Americas where the pest can feed on more than 100 plant species. SAW was recently detected in West and Central Africa, feeding on various crops including cassava, cotton, amaranth and tomato. The current work was carried out to predict the potential spatial distribution of SAW and four of its co‐evolved parasitoids at a global scale using the maximum entropy (Maxent) algorithm. RESULTS: SAW may not be a huge problem outside its native range (the Americas) for the time being, but may compromise crop yields in specific hotspots in coming years. The analysis of its potential distribution anticipates that the pest might easily migrate east and south from Cameroon and Gabon. CONCLUSION: The models used generally demonstrate that all the parasitoids considered are good candidates for the biological control of SAW globally, except they will not be able to establish in specific climates. The current paper discusses the potential role of biological control using parasitoids as a crucial component of a durable climate‐smart integrated management of SAW to support decision making in Africa and in other regions of bioclimatic suitability. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Clean cooking fuels and technologies remain essential in addressing the climate crises, environmental degradation, deforestation, air pollution, health complications, and poverty. Nevertheless, many countries in Africa lack access to clean fuels and technologies for cooking. The extant literature remains scarce on the determinants of clean cooking fuels and technologies using macroeconomic indicators covering many African countries in a single study. This article addresses this gap using panel data from 38 African countries. The paper shows that rural population, particulate matter emission, and natural resources depletion significantly decreased access to clean cooking fuels and technologies in the long run while the gross domestic product (GDP) per capita significantly increased access to clean cooking fuels and technologies in the long run in Africa. The results show a bi‐causal relationship between clean cooking fuels and technologies and rural population, GDP per capita, natural resource depletion, and particulate emissions damage. Understanding the determinants of clean cooking fuels and technologies will expand insights into addressing challenges associated with particulate emission damages. Governments in Africa should target improvements in GDP per capita, promote advocacies, and advocate for investments to address the limited access to clean cooking fuels and technologies, particularly for the rural poor. [ABSTRACT FROM AUTHOR]

As a global industry, sport makes potentially significant contributions to climate change through both carbon emissions and influence over sustainability practices. Yet, evidence regarding impacts is uneven and spread across many disciplines. This paper investigates the impacts of sport emissions on climate and identifies knowledge gaps. We undertook a systematic and iterative meta‐analysis of relevant literature (1992–2022) on organized and individual sports. Using a defined search protocol, 116 sources were identified that map to four sport‐related themes: (1) carbon emissions and their measurement; (2) emissions control and decarbonization; (3) carbon sinks and offsets; and (4) behavior change. We find that mega sport events, elite sport, soccer, skiing, and golf have received most attention, whereas grass‐roots and women's sport, activity in Africa and South America, cricket, tennis, and volleyball are understudied. Other knowledge gaps include carbon accounting tools and indicators for smaller sports clubs and active participants; cobenefits and tradeoffs between mitigation‐adaptation efforts in sport, such as around logistics, venues, sports equipment, and facilities; geopolitical influence; and scope for climate change litigation against hosts and/or sponsors of carbon‐intensive events. Among these, researchers should target cobenefits given their scope to deliver wins for both climate mitigation and risk management of sport. [ABSTRACT FROM AUTHOR]

The literature on climate exposures and human migration has focused largely on assessing short‐term responses to temperature and precipitation shocks. In this paper, we suggest that this common coping strategies model can be extended to account for mechanisms that link environmental conditions to migration behavior over longer periods of time. We argue that early‐life climate exposures may affect the likelihood of migration from childhood through early adulthood by influencing parental migration, community migration networks, human capital development, and decisions about household resource allocation, all of which are correlates of geographic mobility. After developing this conceptual framework, we evaluate the corresponding hypotheses using a big data approach, analyzing 20 million individual georeferenced records from 81 censuses implemented across 31 countries in tropical Africa, Latin America, and Southeast Asia. For each world region, we estimate regression models that predict lifetime migration (a change in residence between birth and ages 30–39) as a function of temperature and precipitation anomalies in early life, defined as the year prior to birth to age four. Results suggest that early‐life climate is systematically associated with changes in the probability of lifetime migration in most regions of the tropics, with the largest effects observed in sub‐Saharan Africa. In East and Southern Africa, the effects of temperature shocks vary by sex and educational attainment and in a manner that suggests women and those of lower socioeconomic status are most vulnerable. Finally, we compare our main results with models using alternative measures of climate exposures. This comparison suggests climate exposures during the prenatal period and first few years of life are particularly (but not exclusively) salient for lifetime migration, which is most consistent with the hypothesized human capital mechanism. [ABSTRACT FROM AUTHOR]

Externalities, such as air pollution and increased occupational hazards, resulting from global trends in climate change, rapid industrialization, and rapidly increasing populations are raising global concerns about the associated health risks. The Global Environmental and Occupational Health Hub for Eastern Africa was established to address some of these problems at national and regional levels through focused training and applied research that would yield evidence supporting policies and investments to mitigate risks of increasing environmental threats throughout the Eastern African region. Emphasis has been placed on air pollution, a leading risk factor for global mortality, accounting for over 7 million premature deaths or 8.7% of the 2017 global mortality burden. Despite the enormous disease burden that air pollution causes, global investment in air pollution monitoring and research capacity building in low‐middle and middle‐income countries have been inadequate. This study outlines the activities the Hub has undertaken in planning for and carrying out its initial capacity building and building its primary research programs and identifies central lessons that can inform other large global research partnerships. Plain Language Summary: Air pollution and increased occupational hazards resulting from climate change and rapid industrialization are damaging health. The Global Environmental and Occupational Health (GEOHealth) Hub for Eastern Africa was established to address some of these problems at national and regional levels through training and applied research. This paper describes the activities the Hub has undertaken during its first five years and identifies central lessons that can inform other large global research partnerships. Key Points: Environmental and occupational health challenges remain significant throughout Eastern AfricaThe Eastern Africa GEOHealth Hub is well positioned to build its research and dissemination activitiesThe Hub serves as a model for other large, international research collaborations [ABSTRACT FROM AUTHOR]

This paper examines potential land use changes in Africa under climate change by building an integrated model of crop management, animal husbandry, and forestry. Using micro-level decisions from around 9000 household surveys in 11 countries, we analyze the choice of land types across the landscape with a multinomial discrete choice model. The choices and future adaptation measures are analyzed as a mosaic based on the typology of Agro-Ecological Zones. The results indicate that if climate becomes hotter and drier, Africa will adapt by increasing a joint production of crops and animals, especially in the lowland savannahs. On the other hand, if climate becomes wetter, it will switch more to forests, either with crops or with both crops and livestock, especially in the mid and high elevation humid zones. Forestry will play a significant role in adaptation when a substantial increase in precipitation makes animal husbandry an unattractive alternative. [ABSTRACT FROM AUTHOR]

Studies of climate change from both natural science and social science disciplines are increasingly turning their focus to the issue of extreme events. Extreme heat waves, storms, droughts, and coastal inundations pose a disproportionate risk to human life, livelihood, and capital across the world. In the Global South, including Africa, much of the adverse impacts come from hydroclimate extremes as people with limited means are often highly vulnerable to climate shocks. The focus of this review paper will be on hydroclimate extremes in Africa. This paper will consider observations and modeling studies of heat extremes, drought, and flooding from heavy rainfall, along with observations and modeling studies of extreme streamflow events in major rivers and extremes of lake level. This being said, observations of trends in extreme events need to be situated in a context of understanding regional hydroclimate variability. There is tremendous diversity and variability in the hydroclimate of Africa and many extreme events, especially of precipitation and streamflow are associated with patterns of natural variability on a range of time scales. [ABSTRACT FROM AUTHOR]

Fires were historically rare in tropical forests of West and Central Africa, where dense vegetation, rapid decomposition, and high moisture limit available fuels. However, increasing heat and drought combined with forest degradation and fragmentation are making these areas more susceptible to wildfires. We evaluated historical patterns of Moderate Resolution Imaging Spectroradiometer active fires in African tropical forests from 2003 to 2021. Trends were mostly positive, particularly in the northeastern and southern Congo Basin, and were concentrated in areas with high deforestation. Year‐to‐year variation of fires was synchronized with increasing temperature and vapor pressure deficit. There was anomalously high fire activity across the region during the 2015–2016 El Niño. These results contrast with the drier African woodlands and savannas, where fire has been decreasing. Further attention to fires in African tropical forests is needed to understand their global impacts on carbon dynamics and their local implications for biodiversity and human livelihoods. Plain Language Summary: Fires have historically been rare in the moist tropical forests of West and Central Africa. However, these forests are becoming more vulnerable to fire because climate change is causing higher temperatures and drought stress in the tropics. Human activities such as agriculture, logging, and mining also fragment the remaining forests and make them more susceptible to fire. We used measurements of actively burning fires from Earth observing satellites to study how the amount of fire in African tropical forests has changed from 2003 to 2021. There were several areas with strong trends of increasing fire, mainly in the Congo Basin. In contrast, there were almost no locations where fire was decreasing. The increasing fire trends occurred in locations where deforestation was occurring and climate was becoming warmer and drier. During 2015–2016 global weather patterns caused by an exceptionally strong El Niño event were associated with higher‐than‐normal fire activity throughout the tropical forests in West and Central Africa. Increasing fire is a concern because it can release greenhouse gasses into the atmosphere, reduce the amount of carbon stored in the African tropics, degrade habitats for species that live in tropical forests, and decrease the amounts of wood, food, medicine and other resources that forests provide for humans. Key Points: Active fire detections increased from 2003 to 2021 across Central Africa, with positive fire trends concentrated in the Congo BasinFire increased in areas with high deforestation and the trends were synchronized with increasing temperature and vapor pressure deficitThere was higher‐than‐usual fire activity in tropical African forests associated with the exceptionally strong 2015–2016 El Niño event [ABSTRACT FROM AUTHOR]

ABSTRACT Recent special reports on climate extremes have shown evidences of changes in the patterns of climate extremes at global, regional and local scales. Understanding the characteristics of climate extremes at regional and local levels is critical not only for the development of preparedness and early warning systems, but is also fundamental in the development of any adaptation strategies. There is still very limited knowledge regarding the past, present and future patterns of climate extremes in the Greater Horn of Africa (GHA). This study, which was supported by the World Bank Global Facility for Disaster Reduction and Recovery (WB-GFDRR) and implemented by the World Meteorological Organization, was organized in terms of three workshops with three main objectives; (1) analysis of daily rainfall and temperature extremes for ten countries in the GHA region using observed in situ data running from 1971 to 2006, (2) assessing whether the United Kingdom Met-office and Hadley centre Providing REgional Climates for Impact Studies (UK-PRECIS) modelling system can provide realistic representation of the past and present climate extremes as observed by available in situ data, and (3) studying the future regional climate extremes under different scenarios to further assess the expected changes in climate extremes. This paper, therefore, uses the outputs of these workshops and also includes post-workshop analyses to assess the changes of climate extremes within the GHA. The results showed a significant decrease in total precipitation in wet days greater than 1 mm and increasing warm extremes, particularly at night, while cold extremes are decreasing. Considering a combination of geophysical models and satellite gravimetry observations from the Gravity Recovery and Climate Experiment (GRACE) mission in the frame of GRACE daily Kalman-smoothing models, for the years 2002 to 2010, we explored a decline in total water storage variations over the GHA. [ABSTRACT FROM AUTHOR]

In this paper, we study the impact of climate change on river regimes in several parts of Africa, and we look at the most probable causes of these changes either climatically or anthropogenically driven. We study time series of updated monthly and annual runoff of rivers of North Africa, West Africa (Sahelian and humid tropical regions) and Central Africa, including the largest river basins: Niger and Volta rivers in West Africa, and Congo and Ogooue rivers in Central Africa. The recent years are studied in the perspective of multi-decadal variability. In West Africa and in a part of Central Africa, the climate has changed since 1970, and rainfall has not returned to previous annual amounts, except in Equatorial Africa. The consequences of the long-lasting drought are, depending on the area concerned, the modification of seasonal regimes (Equatorial area), the groundwater table decrease (Tropical humid area) and the land cover degradation (Sahelian area). The increasing number of dams and of agricultural areas also plays a major role on the modification of river regimes. The population increase will continue to impact on the environment: land cover change, deforestation, agriculture and increasing number of dams will be associated with a reduction of water and sediment discharges to the sea, and major impacts on downstream ecosystems and coastal areas. It seems necessary to share with stakeholders a comprehensive approach of the water cycle from the basin to the sea, to prevent long-lasting damages to ecosystems and infrastructures. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Weather and climate services (WCS) are expected to improve the capacity of Africa's agricultural sector to manage the risks of climate variability and change. Despite this, a lack of evidence prevents a realistic analysis of whether such services are delivering on their potential. This paper reviews 66 studies that have evaluated outcomes and/or impacts of agricultural WCS in Africa, highlighting areas that have received relatively more attention as well as persistent gaps. While the evaluation of WCS outcomes is relatively straightforward, estimates of the number of people who access and use these services are uneven (covering a small number of communities in 23 of 54 African countries) and highly variable (with access estimates ranging from ~2 to 86%, depending on the service and the population). Meanwhile, 22 documents estimate the impact of WCS with respect to yields and/or income. Developed with a variety of methods, these estimates are also wide ranging and illustrate how impact is conditioned on a number of characteristics of the service, the user, and the context in which both operate. The paper uses lessons developed through this review to develop a "learning agenda," or evidence‐building roadmap, to establish priorities that can guide work to improve the design, delivery, and impact of agricultural WCS in Africa. Priority learning areas include activities that can strengthen the evidence of access, use, and impacts of WCS, along with those that can advance the use and usability of evidence so as to improve the design and targeting of WCS services. This article is categorized under: Assessing Impacts of Climate Change > Evaluating Future Impacts of Climate ChangeVulnerability and Adaptation to Climate Change > Learning from Cases and Analogies [ABSTRACT FROM AUTHOR]

Tropical wetlands have been shown to exhibit high rates of net primary productivity and may therefore play an important role in global climate change mitigation through carbon assimilation and sequestration. Many permanently flooded areas of tropical East Africa are dominated by the highly productive C4 emergent macrophyte sedge, Cyperus papyrus L. (papyrus). However, increasing population densities around wetland margins in East Africa are reducing the extent of papyrus coverage due to the planting of subsistence crops such as Colocasia esculenta (cocoyam). In this paper, we assess the impact of this land use change on the carbon cycle and in particular the impacts of land conversion on net ecosystem carbon dioxide exchange. Eddy covariance techniques were used, on a campaign basis, to measure fluxes of carbon dioxide over both papyrus and cocoyam dominated wetlands located on the Ugandan shore of Lake Victoria. Peak rates of net photosynthetic CO2 assimilation, derived from monthly diurnal averages of net ecosystem exchange, of 28-35 μmol CO2 m−2 s−1 and 15-20 μmol CO2 m−2 s−1 were recorded in the papyrus and cocoyam wetlands, respectively, whereas night-time respiratory losses ranged between 10 and 15 μmol CO2 m−2 s−1 at the papyrus wetland and 5-10 μmol CO2 m−2 s−1 at the cocoyam site. The integration of the flux data suggests that papyrus wetlands have the potential to act as a sink for significant amounts of carbon, in the region of 10 t C ha−1 yr−1. The cocoyam vegetation assimilated ~7 t C ha−1 yr−1 but when carbon exports from crop biomass removal were accounted for these wetlands represent a significant net loss of carbon of similar magnitude. The development of sustainable wetland management strategies are therefore required to promote the dual wetland function of crop production and the mitigation of greenhouse gas emissions especially under future climate change scenarios. [ABSTRACT FROM AUTHOR]

1. The aim of this paper is to investigate mechanisms of reinforcement between two semi-isolated semispecies of the African savannah butterfly Danaus chrysippus. The biogeography of colour genes suggests that four semispecies evolved in once isolated refugia. They expanded their ranges in response to Holocene climatic changes to form a hybrid zone in central-east Africa. 2. Danaus chrysippus is a superspecies within which cycles of alternating cladogenesis and reticulation among semispecies have probably operated over some 4 Myr. Semispecies are inter-fertile but show Haldane rule effects in crosses; gene flow is massive but subject to isolation by distance. 3. One semispecies shows linkage disequilibrium, vis- à-vis others, for haplotype, karyotype (W-linkage of colour genes which function as reproductive isolating barriers) and all-female broods caused by a male-killer endosymbiont. Introgression of colour genes between D. c. dorippus and D. c. chrysippus is constrained by sex linkage and male killing. 4. Reinforcement in hybrid zones comprises allochronic migration, assortative mating, (assumed) sex chromosome incompatibility and sex-ratio distortion. Gene introgression from D. c. dorippus to other semispecies is maintained by a high frequency of backcrossing between hybrid males and females of the latter. [ABSTRACT FROM AUTHOR]

The TreeGOER (Tree Globally Observed Environmental Ranges) database provides information for most known tree species of their environmental ranges for 38 bioclimatic, eight soil and three topographic variables. It is based on species distribution modelling analyses of more than 44 million occurrences. The database can be accessed from https://doi.org/10.5281/zenodo.7922927. Statistics that include 5% and 95% quantiles were estimated for a cleaned and taxonomically standardized occurrence data set with different methods of outlier detection, with estimates for roughly 45% of species being based on 20 or more observation records. Where sufficient representative observations are available, the ranges provide useful preliminary estimates of suitable conditions particularly for lesser‐known species under climate change. Inferred core bioclimatic ranges of species along global temperature and moisture index gradients and across continents follow the known global distribution of tree diversity such as its highest levels in moist tropical forests and the 'odd man out' pattern of lower levels in Africa. To demonstrate how global analyses for large numbers of tree species can easily be done in R with TreeGOER, here I present two case studies. The first case study investigated latitudinal trends of tree vulnerability and compared these with previous results obtained for urban trees. The second case study focused on tropical areas, compared trends in different longitudinal zones and investigated patterns for the moisture index. TreeGOER is expected to benefit researchers conducting biogeographical and climate change research for a wide range of tree species at a variety of spatial and temporal scales. [ABSTRACT FROM AUTHOR]

The interplay of rapid climate change and tectonics drives landscape development, sediment routing, and deposition in early‐stage continental rift systems. The Lake Malawi Rift, in the Western Branch of the East African Rift, is an archetype of a juvenile rift and an ideal natural laboratory for evaluating lacustrine source‐to‐sink systems on orbital or shorter timescales. We examine the interplay of these processes over the past 140 kyr using observations from nested seismic reflection data sets tied to scientific drill cores, which calibrate numerical forward models of this closed sedimentary system. Fault slip rates measured from seismic data drive tectonic displacements in the model. Satellite‐derived precipitation maps constrain modern precipitation and are scaled to previous hydrologic balance studies to reconstruct past climates. Our model reproduces known sediment thicknesses across the rift and accounts for 96% of the estimated siliciclastic sediment deposited over the past 140 kyr. The results demonstrate that the onset of arid climate conditions (140–95 kyr BP) causes extreme drainage adjustments downstream and the formation of mega‐catchments that flow axially into a shallow restricted paleo‐lake. Sedimentation rates during this time are twice the present values due to increased sediment focusing via these axial systems into a much smaller, hydrologically closed lake. As the climate became wetter (95–50 kyr BP), the lake rapidly expanded, decreasing both erosion and sedimentation rates across the rift. This closed‐loop approach allows us to evaluate the role of high‐frequency climate change in modulating basin physiography as well as sediment fluxes in juvenile rift systems. Plain Language Summary: During the earliest stages of continent formation, the movement and deposition of sediment across the changing landscape is driven by the interplay of rapid changes in climate, as well as vertical motions in the Earth surface caused by earthquakes. The deep lakes of eastern Africa, and their catchments are ideal locations to study the interactions between climate and the motions on the Earth surface because they are not deeply buried, deformed, or covered by vast ocean basins. We focus on the evolution of Lake Malawi in response to the interaction of these processes over the past 140 kyr using sub‐surface acoustic images tied to sedimentary records, which help constrain a mathematical model of landscape change. Our model reproduces 96% of the known volume of sediment over the past 140 kyr. The fast onset of a dry climate causes extreme adjustments of rivers into two large systems that flow into a small lake, ∼50 m deep. Wetter conditions cause a rapid expansion and deepening of the lake, causing these larger rivers to split into smaller ones. These results help constrain the early continental margin formation compared to older systems that may be deformed or deeply buried. Key Points: Using a closed‐loop forward modeling approach, we assess the landscape evolution of the Lake Malawi Rift over the past 140 kyrHigh‐frequency fluctuations in climate cause rapid base‐level changes and major drainage adjustments that focus sedimentSediment focusing is twice as high during arid periods and has the potential to prolong fault lifespan [ABSTRACT FROM AUTHOR]

Megaherbivores play a critical role in the ecology of African savannas and grasslands. In addition, these systems are forecast to experience more frequent and severe droughts as a product of changes in the global climate. Thus, the continued conservation of megaherbivores and their associated ecosystems will require a better understanding of how megaherbivores respond to drought by shifting their movement, diet and social behaviour. We address this need by investigating the factors affecting changes in the abundance of common hippopotamus (Hippopotamus amphibius; hereafter: 'hippos') throughout the six major rivers of Kruger National Park, South Africa, during and following the severe drought of 2015/2016. Specifically, we aimed to understand the role of two environmental characteristics that have relevance to hippos and that changed in response to drought: vegetation condition and the extent of pooled surface water. In addition, we investigated the extent to which pre‐drought density affected changes in hippo abundance. Although vegetation and daytime refugia both appeared to influence pre‐drought hippo abundance, these factors were less important to the change in hippo abundance related to the drought. Instead, the response to drought was most strongly related to the pre‐drought abundance of hippos, where river segments supporting more than 50 individuals prior to the drought in 2015 decreased by more than half on average. Furthermore, we show that the degree of aggregation decreased from 2015 to 2016 because of the drought, but then began to increase again as the rains returned in 2017. Our results suggest that in addition to the large pools that support large aggregations of hippos in typical years, additional smaller pools are likely important for accommodating this drought‐induced dispersion. However, maintaining this distribution of pools will likely become more challenging as southern Africa's population and water demands increase. [ABSTRACT FROM AUTHOR]

Climate sensitivity of infectious diseases is discussed in many studies. A quantitative basis for distinguishing and predicting the disease impacts of climate and other environmental and anthropogenic driver‐pressure changes, however, is often lacking. To assess research effort and identify possible key gaps that can guide further research, we here apply a scoping review approach to two widespread infectious diseases: Lyme disease (LD) as a vector‐borne and cryptosporidiosis as a water‐borne disease. Based on the emerging publication data, we further structure and quantitatively assess the driver‐pressure foci and interlinkages considered in the published research so far. This shows important research gaps for the roles of rarely investigated water‐related and socioeconomic factors for LD, and land‐related factors for cryptosporidiosis. For both diseases, the interactions of host and parasite communities with climate and other driver‐pressure factors are understudied, as are also important world regions relative to the disease geographies; in particular, Asia and Africa emerge as main geographic gaps for LD and cryptosporidiosis research, respectively. The scoping approach developed and gaps identified in this study should be useful for further assessment and guidance of research on infectious disease sensitivity to climate and other environmental and anthropogenic changes around the world. Plain Language Summary: This study looks at how the effects of changes in climate and other environmental and anthropogenic factors are addressed in research on two widespread infectious diseases: Lyme disease (LD) (tick‐borne) and cryptosporidiosis (water‐borne). By a scoping review of existing research publications, the study identifies key gaps that need to be bridged in future research. For LD, more research is needed on water‐related and socioeconomic factors and their climate linkages, while for cryptosporidiosis, land‐related factors and their linkages with climate need further exploration. For both diseases, the interactions between host and parasite communities and their changes along with those in climate and other environmental factors emerge as insufficiently studied. Geographically, research is lacking for LD in Asia and cryptosporidiosis in Africa. By identifying and highlighting these research gaps, this study aims to guide future research on how changes in climate and other factors, and their interlinkages affect these infectious diseases around the world. Key Points: Studies on Lyme disease (LD) and cryptosporidiosis relationships with climate lack coupling with other environmental and anthropogenic factorsDriver‐pressure interactions with host and parasite communities are generally understudiedAsia and Africa are main geographic research gaps for LD and cryptosporidiosis research, respectively [ABSTRACT FROM AUTHOR]

Regional assessments of the wind erosion risk are rare and vary due to the methods used and the available data to be included. The adaptation of existing methods has the advantage that the results can be compared directly. We adopted an already successfully applied methodology (ILSWE—applied in East Africa), to investigate the spatiotemporal variability of the wind erosion risk between 2005 and 2019 in Southern Africa. The approach integrates climatic variables, a vegetation index, and soil properties to describe the potential impact of wind erosion at the landscape scale. The annual and seasonal variability is determined by the vegetation cover, whereas droughts and strong El Niño events had only regional effects. We estimated that 8.3% of the study area experiences a moderate to elevated wind erosion risk over the 15‐year period with annual and inter‐annual fluctuations showing a slight upward trend. In general, the desert and drylands in the west have the highest proportion of risk areas, the moist forests in the east are characterized by a very low risk of wind erosion, while the grasslands, shrublands, and croplands in the interior most likely react to changes of climatic conditions. The validation process is based on a comparison with the estimated frequency of dust storms derived from the aerosol optical depth and angstrom exponent and revealed an overall accuracy of 65%. The results of this study identify regions and yearly periods prone to wind erosion to prioritize for further analysis and conservation policies for mitigation and adaptation strategies. [ABSTRACT FROM AUTHOR]

Throughout Earth's history, dust deposits have been considered sensitive markers of fluctuations in global atmospheric circulation patterns. However, the identification of ancient dust deposits remains problematic, as their massive (structureless) nature impedes an unequivocal classification. In southern Africa, the Lower Jurassic Clarens Formation is dominated by intriguing structureless sandy siltstones that have been interpreted as loess even though classical diagnostic outcrop‐scale loess features are not observed. In this study, we utilized grain characteristics such as size, shape, sorting and fabric to assess the origin of these ubiquitous massive beds, as compared to strata with a known origin in the unit. Based on these grain characteristics, the massive beds can be grouped into six different facies types (Facies 1–6). Facies 1 has very similar grain features to the large‐scale cross‐bedded strata and thus it is interpreted as migrating dune deposits, only apparently massive. The dominant grain size with a large proportion of very fine‐grained sand and the random grain fabric suggests that Facies 2 resulted from sandy dust fall (short‐term suspension), whereas Facies 3 is interpreted as aeolian dust, having features consistent with modern and ancient loess due to its dominant silt grain size and random grain fabric. Features in Facies 4 are undiagnostic and could reflect a range of aeolian processes, although a dominant silt grain size may suggest an overwhelming loess component. Facies 5 and 6 show primary aeolian signatures with the preferred grain orientation being evidence of reworking in an aqueous setting (e.g., lake, stream). These six facies types represent a spectrum of depositional processes that occurred in response to erg migration and climatic changes along this Early Jurassic erg margin. Their facies diversity is evidence for: (1) dry and windy conditions in SW Gondwana during the Sinemurian to Pliensbachian, and (2) reworking of the aeolian sediments in various fluvial and lacustrine settings during the development of one of the largest known sand seas in Earth's history. [ABSTRACT FROM AUTHOR]

Summary: Motivation: Communities across the global south use their rich indigenous and local knowledge (ILK) to predict weather events and climate hazards. ILK may assist efforts to address climate change challenges in Africa and make subsequent decisions regarding climate adaptation. Purpose: The article documents evidence of the ILK's potential in reducing vulnerability to climate change and/or improving the resilience of communities. The study also reflects on major barriers that hinder the improved mainstreaming of ILK into adaptation strategies. Methods and approach: The present study uses two main methods: a literature review and a presentation of case studies from a sample of African countries where ILK informs adaptation options, including indigenous land‐tenure practices and weather prediction. The selected case studies highlight the historical legacy of ILK and its effectiveness in reducing vulnerability and the impacts of climate change. Findings The results indicate that, despite being acknowledged as a valuable resource for climate adaptation, current national adaptation policies on the African continent still show serious gaps in effectively integrating ILK systems within the legal frameworks to reduce vulnerability. Policy implications: ILK should be better integrated with modern climate change adaptation strategies to anticipate more effective responses. Both rural communities and relevant government agencies should complement the use of ILK with climate change strategies, so as to maximize its contribution to the effective implementation of climate change policies. [ABSTRACT FROM AUTHOR]

Indian Ocean sea surface temperatures impact precipitation across the basin through coupled ocean‐atmosphere responses to changes in climate. To understand the hydroclimate response over the western Indian Ocean and equatorial east Africa to different forcing mechanisms, we present four new proxy reconstructions from core VM19‐193 (2.98°N, 51.47°E) that span the last 250 ky. Sub‐surface water temperatures (Sub‐T; TEX86) show strong precessional (23 ky) variability that is primarily influenced by maximum incoming solar radiation (insolation) during the Northern Hemisphere spring season, likely indicating that local insolation dominates the upper water column at this tropical location over time. Leaf waxes, on the other hand, reflect two different precipitation signals: δ13Cwax (in phase with boreal fall insolation) is likely reflecting vegetation changes in response to local rainfall over east Africa, whereas δDprecip (primarily driven by boreal summer insolation) represents changes in regional circulation associated with the summer monsoon. Glacial‐interglacial changes in ocean temperatures support glacial shelf exposure over the Maritime Continent in the eastern Indian Ocean and the subsequent weakening of the Indian Walker Circulation as a mechanism driving 100 ky climate variability across the tropical Indo‐Pacific. Additionally, the 100 ky spectral power in δDprecip supports a basin‐wide weakening of summer monsoon circulation in response to glacial climates. Overall, the proxy records from VM19‐193 indicate that both precession and glacial‐interglacial cycles exert control over hydroclimate at this tropical location. Key Points: New multi‐proxy reconstructions from the tropical western Indian Ocean show both precession and glacial‐interglacial variabilityA new precipitation isotope record likely reflects large‐scale Indian summer monsoon circulation changes over timeGlacial‐scale changes in upper water column structure across the Indian Ocean support shelf exposure as a primary hydroclimate influence [ABSTRACT FROM AUTHOR]

Southern Africa, with its vast arid to semiarid areas, is considered vulnerable to precipitation changes and amplifying weather extremes. However, during the last 100 ka, huge lakes existed in the currently dry central Kalahari. It has been suggested that these lakes could have existed due to altered atmospheric circulation pattern, leading to an increase in precipitation or to changes in the annual precipitation distribution. Past climate changes are recorded in paleo‐archives, yet, for a proper interpretation of paleo‐records, for example, from sedimentological archives or fossils, it is essential to put them in a context with recent observations. This study's objective is, therefore, to analyze spatially differing annual precipitation distributions at multiple locations in southern Africa with respect to their stable water isotope composition, moisture transport pathways, and sources. Five different precipitation distributions are identified by end‐member modeling and respective rainfall zones are inferred, which differ significantly in their isotopic compositions. By calculating backward trajectories, different moisture source regions are identified for the rainfall zones and linked to typical circulation patterns. Our results furthermore show the importance of the seasonality, the amount effect, and the traveled distance of the moisture for the general isotopic composition over the entire southern Africa. The identified pattern and relationships can be useful in the evaluation of isotope‐enabled climate models for the region and are potentially of major importance for the interpretation of stable water isotope composition in paleo‐records in future research. Key Points: We identified five different annual precipitation distributions in southern Africa that cluster in space and define rainfall zonesLagrangian source diagnostic shows that the rainfall zones have notably different moisture sourcesThe isotopic composition differs significantly between rainfall zones [ABSTRACT FROM AUTHOR]

Soil erosion rates are high in many parts of Southern Africa, and are likely to rise because of climate change. Suspended sediment loads (SSL) and yields (SSY) are used to measure and benchmark soil erosion and/or sediment transport rates and determine trajectories of change. Some modelled SSY are available for Southern African catchments, but there is a dearth of contemporary observed data. Northern hemisphere approaches to suspended sediment measurement and the calculation of loads and yields are often unsuited to Southern Africa: locally appropriate methods are required. The manual, flood‐focused suspended sediment sampling programme that we implemented in the eroded and data‐scarce Tsitsa River catchment (Eastern Cape, South Africa) monitored four sub‐catchments from December 2015 to June 2019 at a sub‐daily timestep. We used a discharge‐weighted interpolation SSL estimator, investigating the effects of catchment area, hydrological regime, and sampling strategy on SSL, SSY, and variability, comparing our estimates with modelled results. Discharge increased with catchment area whilst flashiness (expressed by the Richards‐Baker Flashiness Index) mainly decreased, and was similar to that of North American catchments. The sampling frequency required to maintain precision was inversely related to catchment area. Mean annual SSL ranged from 18 121 t year−1 in the 204 km2 Gqukunqa River catchment to 984 267 t year−1 in the 1452 km2 Inxu River catchment. Mean annual SSY ranged from 61 t km2 year−1 in the 432 km2 Pot River catchment to 678 t km2 year−1 in the Inxu River catchment. Data stratification to limit sampling to wet‐season flows did not significantly impact SSL estimates, but year‐round sampling is required to maintain the citizen‐technician sampling network through regular income. Modelled SSY estimates were higher than our measured estimates. Our approach to suspended sediment sampling, load and yield estimation is robust, sustainable, precise, and can be adapted for similar, remote catchments. [ABSTRACT FROM AUTHOR]

Many will remember the 1990s alarmist narratives of how a human tide of up to a billion climate refugees would flood "our" borders by 2050. By 2011, a new character joined the discourse: the trapped figure. No longer would climatically vulnerable people be forced to move, they could also end up immobile. This review examines the narratives that surround the trapped figure. The article highlights the trapped figure's (i) characterisation, (ii) geography, and (iii) storytellers. The material includes the 2011 Foresight Report, 64 English peer‐reviewed journal articles, and seven UNFCCC policy reports. The textual analysis furthers our understanding of the values that shape the meaning of the trapped figure within the wider discursive economy. Out of the 64 articles, 48 located the trapped figure in Asia, while 34 placed the figure in Africa. Meanwhile, the majority of articles—62 in total—were written by scholars based at European research institutes. The study shows that the trapped figure, much as the mythical climate refugee and migrant, is constructed as both a victim in need of rescuing and as an ambiguous security threat. It is ethically problematic that planned relocation was often put forward as an effective tool to "move" the figure out of harm's way. The review also found a range of binary opposites in the discourse on trapped populations, including those of order–disorder, freedom–unfreedom, and victim–savior. This suggests that however well‐intentioned the liberal discourse on trapped populations appear, it remains embedded in power relations which demands for critical scrutiny. This article is categorized under:Social Status of Climate Change Knowledge > Sociology/Anthropology of Climate KnowledgeClimate and Development > Sustainability and Human Well‐BeingPerceptions, Behavior, and Communication of Climate Change > Perceptions of Climate ChangeClimate, Nature, and Ethics > Ethics and Climate Change [ABSTRACT FROM AUTHOR]

Climate change is predicted to affect species in aquatic ecosystems. In Africa, factors that may influence the responses of aquatic species are poorly studied and challenging to predict. In this study, we examined the potential distribution of three aquatic fern species in the genus Azolla in Africa under projected climate change scenarios. MaxEnt was used to create ecological niche models of the three species using occurrence data and environmental variables. All models had satisfactory AUC and TSS values, indicating high prediction precision (AUC and TSS > 0.801). Results showed that elevation and precipitation were the most important variables limiting the species' expansion in the future. In addition, we observed significant variations in the climatic niches of the three species and their distinct climatically appropriate regions. The current potential distribution ranges for the species varied between 2,328,726 km2 and 4,026,363 km2. According to the model predictions for the current period, the potential range of Azolla species extended outside the known and recorded locations; however, under future climate conditions, the species were projected to lose between 8.1% and 48% of their suitable habitats due to climate change. Our findings can be used to develop sustainable conservation measures for aquatic species and raise awareness about the effects of climate change. [ABSTRACT FROM AUTHOR]

Climate change is expected to have important implications for human mobility. This article discusses and contextualizes key insights from a recently published study by Thalheimer, Williams, van der Geest, and Otto in Earth's Future (2021), https://doi.org/10.1029/2020EF001958. The authors synthesize findings from the climate science and impact literature, among others from the IPCC Special Report on Global Warming of 1.5 °C, to explore the role of climatic drivers for human mobility in African drylands. Facing a number of economic, social, and political challenges, these areas are highly vulnerable to global warming and related risks. Climate mobility in this region is the outcome of complex interactions between individual and contextual factors shaping peoples' needs and incentives to move as well as their constraints. As the authors highlight, climate change can influence mobility outcomes through a number of channels, including impacts on food and water security, poverty and livelihood risks, and conflicts. These impacts are relevant for both rural areas and cities, with the latter representing a primary destination for climate‐induced migration in Africa. The complexity and diversity of the climate mobility nexus call for integrative approaches in science and policy that bridge different disciplines and policy sectors. These approaches should be based on fair, equal, and inclusive processes of knowledge production, transfer, and implementation that involve a number of stakeholders. Inclusive deliberations and partnerships across fields and sectors are key elements to comprehensively studying and addressing the realities and manifold challenges faced by both mobile and immobile populations. Key Points: Drylands in Africa are highly exposed and vulnerable to climate change impacts with important implications for human mobilityClimate mobility is the outcome of complex interactions between individual and contextual factors shaping mobility decisions, outcomes, and risksIntegrative approaches in science and policy are needed to address the complex nexus between climate change and human mobility [ABSTRACT FROM AUTHOR]

The article presents the discussion on mitigating climate change. Topics include rural Australia requiring a policy framework focusing on the whole population, new ways of working, embracing technology, prevention and rural autonomy; and communities in terms of loss of human life, damage to property, destruction of crops, loss of livestock, and environmental and infrastructural damage.

Despite their importance for biodiversity and ecosystem services, wetlands are among the most threatened ecosystems globally. The conservation of many migratory waterbirds depends on the conservation of a network of key sites along their flyways. However, the suitability of these sites is changing under climate change, and it is important that management of individual sites in the network adapts to these changes. Using bioclimatic models that also account for changes in inundation, we found that projected climate change will reduce habitat suitability for waterbirds at 57.5% of existing Critical Sites within Africa‐Eurasia, varying from 20.1% in Eastern Europe to 87.0% in Africa. African and Middle East sites are particularly threatened, comprising 71 of the 100 most vulnerable sites. By highlighting priority sites for conservation and classifying Critical Sites into Climate Change Adaptation Strategy (CCAS) classes, our results can be used to support the climate change adaptation of both individual sites and the entire site network. [ABSTRACT FROM AUTHOR]

Seasonal climate forecasts have been promoted as a means to increase the resilience of marginal groups in Africa. The manifestations of this are still to be seen. This paper argues that successful dissemination and adoption of the forecast requires an in-depth profile of the characteristics and needs of user groups. The case study of a mountainous village in southern Lesotho is used to highlight the decisions which one group of marginal users – smallholder farmers – might make in response to the forecast. A participatory role-play exercise explores what information households presently receive and how new climate forecast information could be integrated into seasonal decision making. Results show that there are a number of low-input options available to these farmers for responding to the forecast. Adoption, however, is going to require repeated exposure to the forecast in conjunction with forecast development that is suited to users’ needs. The case study is linked back to the larger scale by suggesting paths that seasonal climate forecast development could take if it is to contribute to improving livelihood sustainability among marginal groups. [ABSTRACT FROM AUTHOR]

Targeted adaptation to near‐term climate change requires accurate, reliable, and actionable climate information for the next few decades. Climate projections simulate the response to radiative forcing, but are subject to substantial uncertainties due to internal variability. Decadal climate predictions aim to reduce this uncertainty by initializing the simulations using observations, but are typically limited to the next 10 years. Here, we use decadal predictions to constrain climate projections beyond the next decade and demonstrate that accounting for climate variability improves regional projections of 20‐year average temperatures. Applying this constraint to climate projections of the near future until 2035, summer temperatures over land regions in Asia and Africa tend to show stronger changes within the warming range simulated by the larger, unconstrained, ensemble—consistent with a warm phase in North Atlantic variability. This improved regional climate information can enable tailored adaptation to climate changes in the coming decades. Plain Language Summary: We present a novel approach to reduce the uncertainty from internal variability, which can limit the capability to develop suitable adaptation strategies, in climate projections of the near future. This approach combines information from decadal climate predictions and climate projections to constrain decadal climate variability. We demonstrate that this constraint improves the skill of temperature projections for the next 20 years after starting the prediction. Applying this method to predict the near‐term future until 2035, we find an increased probability of stronger warming during summer in several land regions, consistent with a warm phase in North Atlantic variability. Such improved estimates of near‐term climate change are a promising basis for developing better adaptation strategies and avoiding mal‐adaptation. Key Points: We present a novel approach to reduce the uncertainty and improve the accuracy of near‐term climate projectionsThe method merges decadal predictions with climate projections, constraining the decadal variability in the projectionsThis approach increases the skill of regional temperature projections for the next 20 years [ABSTRACT FROM AUTHOR]

Preserving biodiversity under rapidly changing climate conditions is challenging. One approach for estimating impacts and their magnitude is to model current relationships between genomic and environmental data and then to forecast those relationships under future climate scenarios. In this way, understanding future genomic and environmental relationships can help guide management decisions, such as where to establish new protected areas where populations might be buffered from high temperatures or major changes in rainfall. However, climate warming is only one of many anthropogenic threats one must consider in rapidly developing parts of the world. In Central Africa, deforestation, mining, and infrastructure development are accelerating population declines of rainforest species. Here we investigate multiple anthropogenic threats in a Central African rainforest songbird, the little greenbul (Andropadus virens). We examine current climate and genomic variation in order to explore the association between genome and environment under future climate conditions. Specifically, we estimate Genomic Vulnerability, defined as the mismatch between current and predicted future genomic variation based on genotype–environment relationships modeled across contemporary populations. We do so while considering other anthropogenic impacts. We find that coastal and central Cameroon populations will require the greatest shifts in adaptive genomic variation, because both climate and land use in these areas are predicted to change dramatically. In contrast, in the more northern forest–savanna ecotones, genomic shifts required to keep pace with climate will be more moderate, and other anthropogenic impacts are expected to be comparatively low in magnitude. While an analysis of diverse taxa will be necessary for making comprehensive conservation decisions, the species‐specific results presented illustrate how evolutionary genomics and other anthropogenic threats may be mapped and used to inform mitigation efforts. To this end, we present an integrated conceptual model demonstrating how the approach for a single species can be expanded to many taxonomically diverse species. [ABSTRACT FROM AUTHOR]

Efforts to understand long‐term Indian Ocean dynamics and land‐sea linkages in southeast Africa during periods of significant global and regional climate change have been inhibited by a lack of high‐resolution climate records, particularly during the Plio‐Pleistocene. Here we present new biomarker and pollen records from International Ocean Discovery Program (IODP) Site U1478, located at the Upper Agulhas Confluence near the Limpopo River mouth, to establish environmental conditions at the southeast African margin between 4 and 1.8 Ma and address this spatiotemporal gap. Compound‐specific hydrogen isotopes of terrestrial leaf waxes (δDwax) and TEX86, using marine archaeal lipids, document hydroclimate variability and sea surface temperature (SST), respectively, permitting an onshore‐offshore climate comparison. The U1478 records establish the Limpopo catchment response to the switch in Indonesian Throughflow source waters, the mid‐Pliocene Warm Period, and intensification of Northern Hemisphere glaciations at ∼2.7 Ma. Broad coherence between the δDwax and SST records supports a linkage between Indian Ocean temperatures and southeast African hydroclimate. We hypothesize that additional mechanisms including Indian Ocean cross‐basin SST gradients (ΔSST) and high latitude glaciation acted as hydroclimate controls during the Plio‐Pleistocene. We use ΔSST to evaluate ocean‐atmosphere patterns similar to the Indian Ocean Dipole (IOD) and establish generally wetter conditions in the region associated with positive IOD‐like phases. Additionally, an obliquity signal evident in the δDwax record indicates that glacial‐interglacial variability likely influenced the tropical rain belt position and also controlled rainfall. Hydroclimate and environmental conditions across the Plio‐Pleistocene in southeast Africa may have important implications for regional hominin evolution. Key Points: Site U1478 biomarkers record Plio‐Pleistocene climate changes in southeast Africa, providing regional context for early hominin evolutionIndonesian Throughflow variability, the mid‐Pliocene warm period, and onset of Northern Hemisphere glaciation impacted Limpopo climateHydroclimate and offshore temperatures are linked, but zonal temperature gradients and glacial variability likely also modulated rainfall [ABSTRACT FROM AUTHOR]

Tropical Africa is home to an astonishing biodiversity occurring in a variety of ecosystems. Past climatic change and geological events have impacted the evolution and diversification of this biodiversity. During the last two decades, around 90 dated molecular phylogenies of different clades across animals and plants have been published leading to an increased understanding of the diversification and speciation processes generating tropical African biodiversity. In parallel, extended geological and palaeoclimatic records together with detailed numerical simulations have refined our understanding of past geological and climatic changes in Africa. To date, these important advances have not been reviewed within a common framework. Here, we critically review and synthesize African climate, tectonics and terrestrial biodiversity evolution throughout the Cenozoic to the mid‐Pleistocene, drawing on recent advances in Earth and life sciences. We first review six major geo‐climatic periods defining tropical African biodiversity diversification by synthesizing 89 dated molecular phylogeny studies. Two major geo‐climatic factors impacting the diversification of the sub‐Saharan biota are highlighted. First, Africa underwent numerous climatic fluctuations at ancient and more recent timescales, with tectonic, greenhouse gas, and orbital forcing stimulating diversification. Second, increased aridification since the Late Eocene led to important extinction events, but also provided unique diversification opportunities shaping the current tropical African biodiversity landscape. We then review diversification studies of tropical terrestrial animal and plant clades and discuss three major models of speciation: (i) geographic speciation via vicariance (allopatry); (ii) ecological speciation impacted by climate and geological changes, and (iii) genomic speciation via genome duplication. Geographic speciation has been the most widely documented to date and is a common speciation model across tropical Africa. We conclude with four important challenges faced by tropical African biodiversity research: (i) to increase knowledge by gathering basic and fundamental biodiversity information; (ii) to improve modelling of African geophysical evolution throughout the Cenozoic via better constraints and downscaling approaches; (iii) to increase the precision of phylogenetic reconstruction and molecular dating of tropical African clades by using next generation sequencing approaches together with better fossil calibrations; (iv) finally, as done here, to integrate data better from Earth and life sciences by focusing on the interdisciplinary study of the evolution of tropical African biodiversity in a wider geodiversity context. [ABSTRACT FROM AUTHOR]

Anthropogenic climate change is expected to impact ecosystem structure, biodiversity and ecosystem services in Africa profoundly. We used the adaptive Dynamic Global Vegetation Model (aDGVM), which was originally developed and tested for Africa, to quantify sources of uncertainties in simulated African potential natural vegetation towards the end of the 21st century. We forced the aDGVM with regionally downscaled high-resolution climate scenarios based on an ensemble of six general circulation models (GCMs) under two representative concentration pathways (RCPs 4.5 and 8.5). Our study assessed the direct effects of climate change and elevated CO2 on vegetation change and its plant-physiological drivers. Total increase in carbon in aboveground biomass in Africa until the end of the century was between 18% to 43% (RCP4.5) and 37% to 61% (RCP8.5) and was associated with woody encroachment into grasslands and increased woody cover in savannas. When direct effects of CO2 on plants were omitted, woody encroachment was muted and carbon in aboveground vegetation changed between -8 to 11% (RCP 4.5) and -22 to -6% (RCP8.5). Simulated biome changes lacked consistent large-scale geographical patterns of change across scenarios. In Ethiopia and the Sahara/Sahel transition zone, the biome changes forecast by the aDGVM were consistent across GCMs and RCPs. Direct effects from elevated CO2 were associated with substantial increases in water use efficiency, primarily driven by photosynthesis enhancement, which may relieve soil moisture limitations to plant productivity. At the ecosystem level, interactions between fire and woody plant demography further promoted woody encroachment. We conclude that substantial future biome changes due to climate and CO2 changes are likely across Africa. Because of the large uncertainties in future projections, adaptation strategies must be highly flexible. Focused research on CO2 effects, and improved model representations of these effects will be necessary to reduce these uncertainties. [ABSTRACT FROM AUTHOR]

Producing enough food to feed a growing population is a great future challenge, especially for vulnerable areas in Africa. There is limited understanding of food security under future climate conditions, particularly under the warming target stipulated in the Paris Agreement. Maize is the most widely cultivated crop in Africa. Taking maize as an example, we present an integrated assessment of maize supply and demand under 1.5°C and 2.0°C warming scenarios, considering the combined impacts of climate change, technology development and population increase. We find that global warming of 1.5°C or 2.0°C would shorten maize growth duration, aggravate droughts, and consequently reduce yield with a spatially explicit pattern. Maize yield would decrease more under global warming of 2.0°C versus 1.5°C. Benefit of rising CO2 concentration could not fully offset the yield loss due to climate change under global warming of 1.5°C. Technology development can significantly improve the ratio of maize supply to demand, which is however subject to future projections on population and technology development. Under a reasonable logarithmic technology development scenario, maize security would become worse in most of the countries in Africa. Our findings highlight the importance of technology development and adaptation strategies to meet the challenges of food security in the vulnerable regions. Key Points: Maize yield would decrease more under 2.0 than 1.5°C warming scenarioUnder a reasonable logarithmic technology development scenario, maize security would become worse in most of the countries in AfricaTechnology development and adaptation strategies are essential to meet the challenges of food security in the vulnerable regions [ABSTRACT FROM AUTHOR]

One response to mitigate the impact of climate change on agricultural systems is to develop new varieties that are tolerant to the new range of biotic and abiotic challenges this change causes. This requires access to novel variants of genes for complex adaptive traits. Crop wild relatives (CWRs) are a potentially valuable source of these genes; however, these materials are often difficult to work with and identifying valuable alleles is difficult without substantial investment in prebreeding. In this study, we describe the development of a nested association mapping population for sorghum [Sorghum bicolor (L.) Moench] using two cultivated grain sorghum reference parents and nine wild and exotic sorghum accessions as donors. The donor parents come from the S. bicolor (L.) Moench subsp. verticilliflorum (Steud.) de Wet ex Wiersema & J. Dahlb., S. bicolor (L.) Moench subsp. drummondii (Steud.) de Wet ex Davidse, and S. bicolor (L.) Moench subsp. bicolor margaritiferum taxa and were sampled from a range of environments across Africa. In total, the resource consists of 13 populations and a total of 1,224 lines. The population has been genotyped with diversity array technology (DArT) markers that produced 42,372 unique single nucleotide polymorphism (SNP) markers covering the genome. We determine the utility of the resource for high resolution mapping of complex traits by demonstrating that the exotics contain unique alleles for some example adaptive trait loci and by using the population for genome‐wide association study (GWAS). The resource should provide useful material for plant breeders attempting to deal with the challenges generated by climate change. [ABSTRACT FROM AUTHOR]

Global climate models struggle to simulate both the convection and cloud ice fundamental to lightning formation. We use the first convection‐permitting, future climate simulations for the lightning hot spot of Africa, at the same time utilizing an ice‐based lightning parametrization. Both the model and observations show that lightning over Africa's drier areas, as well as the moist Congo, have more lightning per rainfall than other regions. Contrary to results in the literature, the future projection shows little increase in total lightning (~107 flashes (or 2%) per degree warming). This is a consequence of increased stability reducing the number of lightning days, largely offsetting the increased graupel and updraft velocity driving an increase in lightning per lightning day. The next step is to establish if these results are robust across other models and, if combined with parametrized‐convection models, whether ensemble‐based information on the possible responses of lightning to climate change can be investigated. Plain Language Summary: Lightning depends on ascending air in thunderstorms and the collision of cloud ice particles, which charge the thundercloud. Many climate models have too coarse a resolution to reliably capture these processes. We focus on Africa, which has some of the most frequent lightning in the world. We use a model that is much higher resolution than usual, and this allows us to explicitly simulate the deep convection associated with thunderstorms as well as provide more detailed representation of the distribution of cloud ice particles. Our results show that in drier regions, as well as the much wetter Congo, there is relatively more lightning per kilogram of surface rainfall than there is in other parts of the continent. Lightning does increase across the continent under climate change, but by a relatively small amount. This is despite the number of days with lightning decreasing as the lower atmosphere becomes more stable. On days with lightning, there are more lightning flashes because there is an increase in cloud ice and intensity of convection. This study gives much more detailed information about African lightning than previous work. However, it is a single simulation. Future research should look at these results across other climate models. Key Points: Lightning and its relationship to rainfall vary considerably across Africa, with indication of dry lightning in arid regionsOpposite changes in lightning days and intensity lead to little change in total flashes under climate change, unlike many past studiesGraupel increases are smaller than column water increases, and therefore, lightning intensity mostly increases less than rain intensity [ABSTRACT FROM AUTHOR]

Aim: The high diversity of species in southern Africa has been attributed to geological and palaeoclimatic factors. The timing of radiations in some groups is held to be linked to these geoclimatic trends. Using the Scarabaeinae dung beetle genus, Sisyphus, as a model system, we investigate how geological uplift and climatic changes in the late Cenozoic affected its diversification patterns in southern Africa. Location: Southern Africa. Taxon: The dung beetle genus, Sisyphus Latreille, 1807 (Coleoptera: Scarabaeidae: Scarabaeinae). Methods: A dated molecular phylogeny of southern African Sisyphus was compared with a factor analysis of species distribution data that statistically defined groups of species according to current climatic distribution. We used these climatic clusters to estimate ancestral ranges using the "BioGeoBEARS" R package. A lineage through time plot was calculated using the R package 'APE'. We used Bayesian diversification models (compound Poisson process on mass extinction times) to test hypotheses on how late Cenozoic uplift and climatic changes affected speciation and extinction of Sisyphus. Furthermore, we implemented ecological niche modelling in MaxEnt to predict the habitat suitability of species under present climatic conditions. Results: Four species groups defined from factor analysis of current climatic distribution data are primarily restricted to the moist summer rainfall region in the northeast. Species diversification occurred from the mid‐Miocene until the Pleistocene, during which the central southern African plateau was uplifted in tandem with the advent of winter rainfall and arid climatic zones to the southwest. The ancestor of Sisyphus was centred in eastern low to mid‐altitude areas. Speciation rates were higher in the Miocene to Pliocene, followed by a dramatic drop during the transition to the Pleistocene. Main conclusions: The taxonomic and eco‐climatic diversification of sisyphines is coincident with geological uplift and changes in climate in east‐central southern Africa. However, phylogenetic relationships of southern African Sisyphus species are not homogenously distributed with respect to geography and climate. [ABSTRACT FROM AUTHOR]

Dating population divergence within species from molecular data and relating such dating to climatic and biogeographic changes is not trivial. Yet it can help formulating evolutionary hypotheses regarding local adaptation and future responses to changing environments. Key issues include statistical selection of a demographic and historical scenario among a set of possible scenarios, and estimation of the parameter(s) of interest under the chosen scenario. Such inferences greatly benefit from (a) independent information on evolutionary rate and pattern at genetic markers; and (b) new statistical approaches, such as approximate Bayesian computation‐random forest (ABC‐RF), which provides reliable inference at a low computational cost and the possibility to measure prediction quality at the exact position of the observed data set. Here, we show full potential of the ABC‐RF approach including prior knowledge on microsatellite genetic markers to decipher the evolutionary history of the African arid‐adapted pest locust, Schistocerca gregaria, with support for a southern colonization of Africa, from a low number of founders of northern origin, dating back 2.6 Ky (90% CI: 0.9–6.6 Ky). We verify that this divergence time estimate accurately reflected true divergence time values by computing accuracy at a local posterior scale from simulated pseudo‐observed data sets. The inferred divergence history is better explained by the peculiar biology of S. gregaria, which involves a density‐dependent swarming phase with some exceptional spectacular migrations, rather than a continuous colonization resulting from the continental expansion of open vegetation habitats during more ancient Quaternary glacial climatic episodes. [ABSTRACT FROM AUTHOR]

Aim: Large trees [≥ 70 cm diameter at breast height (DBH)] contribute disproportionately to aboveground carbon stock (AGC) across the tropics but may be vulnerable to changing climate and human activities. Here we determine the distribution, drivers and threats to large trees and high carbon forest. Location: Central Africa. Time period: Current. Major taxa studied: Trees. Methods: Using Gabon's new National Resource Inventory of 104 field sites, AGC was calculated from 67,466 trees from 578 species and 97 genera. Power and Michaelis–Menten models assessed the contribution of large trees to AGC. Environmental and anthropogenic drivers of AGC, large trees, and stand variables were modelled using Akaike's information criterion (AIC) weights to calculate average regression coefficients for all p ossible models. Results: Mean AGC for trees ≥ 10 cm DBH in Gabonese forestlands was 141.7 Mg C/ha, with averages of 166.6, 171.3 and 96.6 Mg C/ha in old growth, concession and secondary forest. High carbon forests occurred where large trees are most abundant: 31% of AGC was stored in large trees (2.3% of all stems). Human activities largely drove variation in AGC and large trees, but climate and edaphic conditions also determined stand variables (basal area, tree height, wood density, stem density). AGC and large trees increased with distance from human settlements; AGC was 40% lower in secondary than primary and concession forests and 33% higher in protected than non‐managed areas. Main conclusions: AGC and large trees were negatively associated with human activities, highlighting the importance of forest management. Redefining large trees as ≥ 50 cm DBH (4.3% more stems) would account for 20% more AGC. This study demonstrates that protecting relatively undisturbed forests can be disproportionately effective in conserving carbon and suggests that including sustainable forestry in programs like reduced emissions for deforestation and forest degradation could maintain carbon dense forests in logging concessions that are a large proportion of remaining Central African forests. [ABSTRACT FROM AUTHOR]

Summary: Biomes are constructs for organising knowledge on the structure and functioning of the world's ecosystems, and serve as useful units for monitoring how the biosphere responds to anthropogenic drivers, including climate change. The current practice of delimiting biomes relies on expert knowledge. Recent studies have questioned the value of such biome maps for comparative ecology and global‐change research, partly due to their subjective origin. Here we propose a flexible method for developing biome maps objectively. The method uses range modelling of several thousands of plant species to reveal spatial attractors for different growth‐form assemblages that define biomes. The workflow is illustrated using distribution data from 23 500 African plant species. In an example application, we create a biome map for Africa and use the fitted species models to project biome shifts. In a second example, we map gradients of growth‐form suitability that can be used to identify sites for comparative ecology. This method provides a flexible framework that (1) allows a range of biome types to be defined according to user needs and (2) enables projections of biome changes that emerge purely from the individualistic responses of plant species to environmental changes. [ABSTRACT FROM AUTHOR]

Freshwater organisms are threatened by changes in stream flow and water temperature regimes due to global climate change and anthropogenic activities. Threats include the disappearance of narrow‐tolerance species and loss of favorable thermal conditions for cold‐adapted organisms. Mayflies are an abundant and diverse indicator of river health that performs important functional roles. The relative importance of key hydro‐environmental factors such as water temperature and flow volumes in structuring these communities has rarely been explored in the tropical regions of Africa. Here, we investigate the response of mayfly species diversity to these factors in the Luvuvhu catchment, a strategic water source area in the arid northeastern region of South Africa. Mayfly larvae were sampled monthly in stones‐in‐current biotopes across 23 sites over a one‐year period. The relationship between these environmental drivers and mayfly diversity was modeled using linear mixed effects models (LMMs) and a model‐based multivariate approach. Threshold Indicator Taxa Analysis (TITAN) was used to model the response of mayfly species to important gradients and identify thresholds of change. Site‐specific characteristic were the most important predictor of mayfly diversity, and there was considerable variation over time, with mayfly diversity peaking during winter. Along this, gradient temperature was the best predictor of assemblage structure, with five out of six reliable indicator species being cold‐adapted, and a community threshold response at 19°C. Results support laboratory‐based thresholds of temperature for mayfly species survival and development, extending empirical evidence to include field‐based observations. Increased global (climate change) and local (riparian vegetation removal, impoundments) changes are predicted to have negative impacts on mayfly diversity and ultimately on ecosystem function. [ABSTRACT FROM AUTHOR]

Aim: During the Plio‐Pleistocene, glacial cycles shaped Northern Hemisphere species' distributions causing range contractions followed by interglacial expansions. In migratory bird species, climatic changes could result in a rapid reshaping of their ranges and/or migratory behaviour, given their dispersal capacity. In this context, it has been suggested that long‐distance North American migratory species could have lost their migratory condition during cold glacial periods, regaining it later in warmer periods. Here, we explored this hypothesis for extant Eurasian‐African migratory bird species. Location: Eurasia and Africa. Taxon: Migratory birds. Methods: We used Species Distribution Models (SDMs) to infer the present and Last Glacial Maximum (LGM) potential distribution of 81 Trans‐Saharan migratory bird species, and reviewed the available bird fossil record for the Plio‐Pleistocene covering Eurasia and Africa. Results: SDMs predicted a reduction of the northern edges of the breeding ranges during the LGM compared to the present. However, the current wintering ranges were somewhat similar in the Pleistocene, with the Saharan desert belt gap being always present through time, not overlapping with their breeding ranges. The fossil record also supports the persistence of migration during the Pleistocene. Main conclusions: The palaeo‐distributions and absence of medullary bone in Pleistocene fossils from wintering Euro‐African migratory species confirm that they were migratory, providing independent support for our models. The hypothesis of the loss of migratory behaviour in these species during the Pleistocene is not supported. Furthermore, the differences in migratory species from Eurasia‐Africa and the Americas can be influenced by geographical differences, the persistence of the Mediterranean basin as climatically suitable area during glaciations and the existence of the Saharan belt. [ABSTRACT FROM AUTHOR]

Coffea canephora (robusta coffee) is the most heat‐tolerant and 'robust' coffee species and therefore considered more resistant to climate change than other types of coffee production. However, the optimum production range of robusta has never been quantified, with current estimates of its optimal mean annual temperature range (22–30°C) based solely on the climatic conditions of its native range in the Congo basin, Central Africa. Using 10 years of yield observations from 798 farms across South East Asia coupled with high‐resolution precipitation and temperature data, we used hierarchical Bayesian modeling to quantify robusta's optimal temperature range for production. Our climate‐based models explained yield variation well across the study area with a cross‐validated mean R2 =.51. We demonstrate that robusta has an optimal temperature below 20.5°C (or a mean minimum/maximum of ≤16.2/24.1°C), which is markedly lower, by 1.5–9°C than current estimates. In the middle of robusta's currently assumed optimal range (mean annual temperatures over 25.1°C), coffee yields are 50% lower compared to the optimal mean of ≤20.5°C found here. During the growing season, every 1°C increase in mean minimum/maximum temperatures above 16.2/24.1°C corresponded to yield declines of ~14% or 350–460 kg/ha (95% credible interval). Our results suggest that robusta coffee is far more sensitive to temperature than previously thought. Current assessments, based on robusta having an optimal temperature range over 22°C, are likely overestimating its suitable production range and its ability to contribute to coffee production as temperatures increase under climate change. Robusta supplies 40% of the world's coffee, but its production potential could decline considerably as temperatures increase under climate change, jeopardizing a multi‐billion dollar coffee industry and the livelihoods of millions of farmers. [ABSTRACT FROM AUTHOR]

Throughout much of the African continent, healthcare systems are already strained in their efforts to meet the needs of a growing population using limited resources. Climate change threatens to undermine many of the public health gains that have been made in this region in the last several decades via multiple mechanisms, including malnutrition secondary to drought‐induced food insecurity, mass human displacement from newly uninhabitable areas, exacerbation of environmentally sensitive chronic diseases, and enhanced viability of pathogenic microbes and their vectors. We reviewed the literature describing the various direct and indirect effects of climate change on diseases with cutaneous manifestations in Africa. We included non‐communicable diseases such as malignancies (non‐melanoma skin cancers), inflammatory dermatoses (i.e. photosensitive dermatoses, atopic dermatitis), and trauma (skin injury), as well as communicable diseases and neglected tropical diseases. Physicians should be aware of the ways in which climate change threatens human health in low‐ and middle‐income countries in general, and particularly in countries throughout Africa, the world's lowest‐income and second most populous continent. [ABSTRACT FROM AUTHOR]

While the anthropogenic impact on ecosystems today is evident, it remains unclear if the detrimental effect of hominins on co‐occurring biodiversity is a recent phenomenon or has also been the pattern for earlier hominin species. We test this using the East African carnivore fossil record. We analyse the diversity of carnivores over the last four million years and investigate whether any decline is related to an increase in hominin cognitive capacity, vegetation changes or climatic changes. We find that extinction rates in large carnivores correlate with increased hominin brain size and with vegetation changes, but not with precipitation or temperature changes. While temporal analyses cannot distinguish between the effects of vegetation changes and hominins, we show through spatial analyses of contemporary carnivores in Africa that only hominin causation is plausible. Our results suggest that substantial anthropogenic influence on biodiversity started millions of years earlier than currently assumed. [ABSTRACT FROM AUTHOR]

Aim: Domestic animals first appeared in the archaeological record in northern Africa c. 9000 years before present and subsequently spread southwards throughout the continent. This geographic expansion is well studied and can broadly be explained in terms of the movement of pastoralist populations due to climate change. However, no studies have explicitly evaluated changes in the climatic niche of these domesticates. A priori, one cannot assume a relationship between the geographic spread of animal production and changes in climatic niche breadth because their relationship is highly variable. Therefore, we investigated Holocene changes in the climatic niche of domestic animals (animal production) and compared these to changes in the climatic niche of hunted terrestrial ungulates. Location: The African continent. Time period: 9000–500 BP. Major taxa studied: Domestic animals, hunted (wild) terrestrial ungulates. Methods: For the first time, we applied methods from environmental niche dynamics to archaeological data to reconstruct and quantify changes in the climatic niche breadth of animal production during the African Holocene. We used faunal remains from archaeological assemblages and associated radiocarbon dates to estimate the proportion of the African climate space used for animal production and hunting at 500‐year intervals. Results: We found that the climatic niche of domestic species broadened significantly with the geographic spread, most notably during the termination of the African Humid Period, whilst no such broadening occurred for the climatic niche of hunted species. Main conclusions: Our results provide a quantitative measure of the extent to which humans have constructed and adapted the climatic niche of animal production to manage their domestic animals across increasingly diverse ecological conditions. By incorporating ecological analysis into estimations of past land use, our methods have the potential to improve reconstructions of land use change, and to provide a foundation on which further niche construction hypotheses may be tested. [ABSTRACT FROM AUTHOR]