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Climate change is a major source of concern in the Middle East and North Africa (MENA) region, and migration is often understood as one of several strategies used by households to respond to changes in climate and environmental conditions, including extreme weather events. This study focuses on the link between climate change and migration. Most micro-level studies measure climate change either by the incidences of extreme weather events or by variation in temperature or rainfall. A few studies have found that formal and informal institutions as well as policies also affect migration. Institutions that make government more responsive to households (for example through public spending) discourage both international and domestic migration in the aftermath of extreme weather events. Migration is often an option of last resort after vulnerable rural populations attempting to cope with new and challenging circumstances have exhausted other options such as eating less, selling assets, or removing children from school. This study is based in large part on new data collected in 2011 in Algeria, Egypt, Morocco, Syria, and the Republic of Yemen. The surveys were administered by in-country partners to a randomly selected set of 800 households per country. It is also important to emphasize that neither the household survey results nor the findings from the qualitative focus groups are meant to be representative of the five countries in which the work was carried, since only a few areas were surveyed in each country. This report is organized as follows: section one gives synthesis. Section two discusses household perceptions about climate change and extreme weather events. Section three focuses on migration as a coping mechanisms and income diversification strategy. Section four examines other coping and adaptation strategies. Section five discusses perceptions about government and community programs.

Palaeoclimate reconstructions of periods with warm climates and high atmospheric CO 2 concentrations are crucial for developing better projections of future climate change. Deep-ocean 1 , 2 and high-latitude 3 palaeotemperature proxies demonstrate that the Eocene epoch (56 to 34 million years ago) encompasses the warmest interval of the past 66 million years, followed by cooling towards the eventual establishment of ice caps on Antarctica. Eocene polar warmth is well established, so the main obstacle in quantifying the evolution of key climate parameters, such as global average temperature change and its polar amplification, is the lack of continuous high-quality tropical temperature reconstructions. Here we present a continuous Eocene equatorial sea surface temperature record, based on biomarker palaeothermometry applied on Atlantic Ocean sediments. We combine this record with the sparse existing data 4 , 5 – 6 to construct a 26-million-year multi-proxy, multi-site stack of Eocene tropical climate evolution. We find that tropical and deep-ocean temperatures changed in parallel, under the influence of both long-term climate trends and short-lived events. This is consistent with the hypothesis that greenhouse gas forcing 7 , 8 , rather than changes in ocean circulation 9 , 10 , was the main driver of Eocene climate. Moreover, we observe a strong linear relationship between tropical and deep-ocean temperatures, which implies a constant polar amplification factor throughout the generally ice-free Eocene. Quantitative comparison with fully coupled climate model simulations indicates that global average temperatures were about 29, 26, 23 and 19 degrees Celsius in the early, early middle, late middle and late Eocene, respectively, compared to the preindustrial temperature of 14.4 degrees Celsius. Finally, combining proxy- and model-based temperature estimates with available CO 2 reconstructions 8 yields estimates of an Eocene Earth system sensitivity of 0.9 to 2.3 kelvin per watt per square metre at 68 per cent probability, consistent with the high end of previous estimates 11 . A 26-million-year record of equatorial sea surface temperatures reveals synchronous changes of tropical and polar temperatures during the Eocene epoch forced by variations in concentrations of atmospheric carbon dioxide, with a constant degree of polar amplification.

The expansion of modern human populations in Africa 80,000 to 60,000 years ago and their initial exodus out of Africa have been tentatively linked to two phases of technological and behavioral innovation within the Middle Stone Age of southern Africa--the Still Bay and Howieson's Poort industries--that are associated with early evidence for symbols and personal ornaments. Establishing the correct sequence of events, however, has been hampered by inadequate chronologies. We report ages for nine sites from varied climatic and ecological zones across southern Africa that show that both industries were short-lived (5000 years or less), separated by about 7000 years, and coeval with genetic estimates of population expansion and exit times. Comparison with climatic records shows that these bursts of innovative behavior cannot be explained by environmental factors alone.

Radiocarbon data from 150 archaeological excavations in the now hyper-arid Eastern Sahara of Egypt, Sudan, Libya, and Chad reveal close links between climatic variations and prehistoric occupation during the past 12,000 years. Synoptic multiple-indicator views for major time slices demonstrate the transition from initial settlement after the sudden onset of humid conditions at 8500 B.C.E. to the exodus resulting from gradual desiccation since 5300 B.C.E. Southward shifting of the desert margin helped trigger the emergence of pharaonic civilization along the Nile, influenced the spread of pastoralism throughout the continent, and affects sub-Saharan Africa to the present day.

The ongoing global warming has caused unprecedented changes in the climate system, leading to an increase in the intensity and frequency of weather and climate extremes. This study uses the sixth phase of Coupled Model Intercomparison Project (CMIP6) data to investigate projected changes in drought events over East Africa (EA) under four Shared Socioeconomic Pathway (SSP) emission scenarios (SSP1-2.6, SSP2-4.5, SSP3-4.0, and SSP5-8.5). The CMIP6 data are bias-corrected using a quantile mapping method, with the Climatic Research Unit's precipitation dataset as reference. Drought is quantified using the standardized precipitation index and different measures of drought are estimated: drought duration, drought frequency, drought severity, and drought intensity. Evaluating the accuracy and reliability of historical data before and after bias correction demonstrates the importance of the approach. The overall distribution after bias correction depicts a close agreement with observation. Moreover, the multi-model ensemble mean demonstrate superiority over individual Global Circulation Models. Projected future changes show enhancement in precipitation over most parts of EA in the far future under different SSP scenarios. However, the arid and semi-arid regions are expected to receive less amount of precipitation, whereas the highlands and lake regions are expected to receive a larger amount of precipitation increase. Furthermore, the dry areas of EA are likely to experience more frequent drought events with longer duration, stronger intensity, and severity in the far future. Overall, this study identifies possible drought hotspots over EA, enabling early preparation for such events.

Ice cap fits CO 2 reduction Around 34 million years ago at the Eocene–Oligocene transition, the Earth entered a global cooling phase that brought the rapid development of a continental-scale ice cap and associated sea level fall. It is generally accepted that declining CO 2 levels were an important factor in this shift from a greenhouse to our current icehouse climate, but the precise relationship between CO 2 and the genesis of the Antarctic ice sheet is not fully understood. Paul Pearson and colleagues use boron isotopes from exceptionally well preserved carbonate microfossils from a recently discovered geological section in Tanzania to estimate atmospheric CO 2 levels before, during and after the Eocene–Oligocene transition. They find that CO 2 dipped below levels thought to generate ice sheet development but then rebounded significantly before declining again. These results confirm the central role of CO 2 in the development of the ice sheet and highlight the nonlinear response of the ice sheet to changing CO 2 concentrations. It is generally accepted that declining carbon dioxide (CO 2 ) levels were an important factor in the Eocene–Oligocene transition about 34 million years ago, when the world shifted from a greenhouse to an icehouse climate. Here, using the boron isotope pH proxy on carbonate microfossils from a recently discovered geological section in Tanzania, atmospheric CO 2 levels before, during and after the climate transition are estimated. Geological and geochemical evidence 1 , 2 , 3 indicates that the Antarctic ice sheet formed during the Eocene–Oligocene transition 4 , 33.5–34.0 million years ago. Modelling studies 5 , 6 suggest that such ice-sheet formation might have been triggered when atmospheric carbon dioxide levels ( ) fell below a critical threshold of ∼750 p.p.m.v., but the timing and magnitude of relative to the evolution of the ice sheet has remained unclear. Here we use the boron isotope pH proxy 7 , 8 on exceptionally well-preserved carbonate microfossils from a recently discovered geological section in Tanzania 9 , 10 to estimate before, during and after the climate transition. Our data suggest that a reduction in occurred before the main phase of ice growth, followed by a sharp recovery to pre-transition values and then a more gradual decline. During maximum ice-sheet growth, was between ∼450 and ∼1,500 p.p.m.v., with a central estimate of ∼760 p.p.m.v. The ice cap survived the period of recovery, although possibly with some reduction in its volume, implying (as models predict 11 ) a nonlinear response to climate forcing during melting. Overall, our results confirm the central role of declining in the development of the Antarctic ice sheet (in broad agreement with carbon cycle modelling 12 ) and help to constrain mechanisms and feedbacks associated with the Earth’s biggest climate switch of the past 65 Myr.

This book is a holistic environmental history of the Middle East and North Africa over the last half millennium. It shows how the intimate connections between peoples and environments shaped political, economic, and social history in startling and often unforeseen ways. Nearly all political powers in the region based their rule on the management and control of natural resources, and nearly all individuals were in constant communion with the natural world. To grasp how these multiple histories were central to the pasts of the Middle East and North Africa, the chapters in this book demonstrate the power of environmental history to open up new avenues of historical research and understanding. The book furthermore traces how the Middle East and North Africa deeply affected the global histories of climate, disease, trade, energy, environmental politics, ecological manipulation, and much more. At the intersection of three continents and as many seas, the Middle East and North Africa have been central to world history for millennia. Studying the ecological implications of these global connections, both for the region itself and for the rest of the world, helps bring the Middle East and North Africa into global history and shows how the region must be an essential part of any understanding of the environments of Eurasia over the last five hundred years.

Coral bleaching due to thermal and environmental stress threatens coral reefs and possibly people who rely on their resources. Here we explore patterns of coral bleaching and mortality in East Africa in 1998 and 2005 in a region where the equatorial current and the island effect of Madagascar interact to create different thermal and physicochemical environments. A variety of temperature statistics were calculated, and their relationships with the degree-heating months (DHM), a good predictor of coral bleaching, determined. Changes in coral cover were analyzed from 29 sites that span >1000 km of coastline from Kenya to the Comoros Islands. Temperature patterns are influenced by the island effect, and there are three main temperature environments based on the rise in temperature over 52 years, measures of temperature variation, and DHM. Offshore sites north of Madagascar that included the Comoros had low temperature rises, low DHM, high standard deviations (SD), and the lowest relative coral mortality. Coastal sites in Kenya had moderate temperature rises, the lowest temperature SD, high DHM, and the highest relative coral mortality. Coastal sites in the south had the highest temperature rises, moderate SD and DHM, and low relative coral mortality. Consequently, the rate of temperature rise was less important than background variation, as reflected by SD and kurtosis measures of sea surface water temperature (SST), in predicting coral survival across 1998. Coral bleaching responses to a warm-water anomaly in 2005 were also negatively related to temperature variation, but positively correlated with the speed of water flow. Separating these effects is difficult; however, both factors will be associated with current environments on the opposite sides of reefs and islands. Reefs in current shadows may represent refugia where corals acclimate and adapt to environmental variation, which better prepares them for rising temperature and anomalies, even though these sites are likely to experience the fastest rates of temperature rise. We suggest that these sites are a conservation priority and should be targeted for management and further ecological research in order to understand acclimation, adaptation, and resilience to climate change.

• Background and Aims Afromontane forest ecosystems share a high similarity of plant and animal biodiversity, although they occur mainly on isolated mountain massifs throughout the continent. This resemblance has long provoked questions on former wider distribution of Afromontane forests. In this study Prunus africana (one of the character trees of Afromontane forests) is used as a model for understanding the biogeography of this vegetation zone. • Methods Thirty natural populations from nine African countries covering a large part of Afromontane regions were analysed using six nuclear microsatellites. Standard population genetic analysis as well as Bayesian and maximum likelihood models were used to infer genetic diversity, population differentiation, barriers to gene flow, and recent and all migration among populations. • Key Results Prunus africana exhibits strong divergence among five main Afromontane regions: West Africa, East Africa west of the Eastern Rift Valley (ERV), East Africa east of the ERV, southern Africa and Madagascar. The strongest divergence was evident between Madagascar and continental Africa. Populations from West Africa showed high similarity with East African populations west of the ERV, whereas populations east of the ERV are closely related to populations of southern Africa, respectively. • Conclusions The observed patterns indicate divergent population history across the continent most likely associated to Pleistocene changes in climatic conditions. The high genetic similarity between populations of West Africa with population of East Africa west of the ERV is in agreement with faunistic and floristic patterns and provides further evidence for a historical migration route. Contrasting estimates of recent and historical gene flow indicate a shift of the main barrier to gene flow from the Lake Victoria basin to the ERV, highlighting the dynamic environmental and evolutionary history of the region.

Knowledge of natural long-term rainfall variability is essential for water-resource and land-use management in sub-humid regions of the world. In tropical Africa, data relevant to determining this variability are scarce because of the lack of long instrumental climate records and the limited potential of standard high-resolution proxy records such as tree rings and ice cores 1 , 2 , 3 . Here we present a decade-scale reconstruction of rainfall and drought in equatorial east Africa over the past 1,100 years, based on lake-level and salinity fluctuations of Lake Naivasha (Kenya) inferred from three different palaeolimnological proxies: sediment stratigraphy and the species compositions of fossil diatom and midge assemblages. Our data indicate that, over the past millennium, equatorial east Africa has alternated between contrasting climate conditions, with significantly drier climate than today during the ‘Medieval Warm Period’ (∼ ad 1000–1270) and a relatively wet climate during the ‘Little Ice Age’ (∼ ad 1270–1850) which was interrupted by three prolonged dry episodes. We also find strong chronological links between the reconstructed history of natural long-term rainfall variation and the pre-colonial cultural history of east Africa 4 , highlighting the importance of a detailed knowledge of natural long-term rainfall fluctuations for sustainable socio-economic development.