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This paper considers skeletal and dental lesions to assess the effects of aridification on two skeletal samples from the Bronze Age in what is now the United Arab Emirates (UAE), located on the eastern end of the Arabian Peninsula. This paper hypothesized that the sample from Qarn al‐Harf (QAH) Tomb 6 would show a greater prevalence of skeletal and dental lesions in comparison with that from QAH Tomb 5, because QAH Tomb 6 dates to a period of aridification when compared with the wetter Wadi Suq period (~2000 B.C.). The skeletal remains from two tombs from QAH cemetery are studied: one dated to the transition period from the Umm an‐Nar to Wadi Suq period (~2000 B.C.) (Tomb 6, n = 141) and one Wadi Suq period tomb (Tomb 5, n = 44; 2000–1600 B.C.). Skeletal and dental lesions, including carious lesions, antemortem tooth loss, dental enamel hypoplasia, periosteal new bone formation, cribra orbitalia, and porotic hyperostosis, were recorded and used to assess differential lived experience. Findings from the two tombs are compared with five contemporary sites of the Umm an‐Nar and Wadi Suq periods. Fisher's exact tests found more statistically significant differences in the prevalence of cribra orbitalia (p = 0.0050) and non‐adult mortality (p = 0.0118) for the QAH Tomb 6 skeletal sample than that from QAH Tomb 5. No other skeletal or dental lesions were significantly different according to Fisher's exact tests. While not significant, periosteal new bone formation rates in QAH 6 in conjunction with cribra orbitalia rates suggest individuals were experiencing stressors that were not impacting QAH Tomb 5 individuals. Skeletal and dental lesion rates are not directly attributable to climate change; however, we argue that intense aridification around 2000 B.C. caused desiccated crops and an increased reliance on marine sources for QAH Tomb 6. This reliance likely promoted nutritionally deficient diets manifesting as observed higher rates of cribra orbitalia and periosteal new bone formation. [ABSTRACT FROM AUTHOR]

Freshwater fishes are facing considerable threats in the Arabian Peninsula which is considered as a highly stressed region in the Middle East. It is predicted that northern Oman is likely to face decreasing rainfall and increasing temperature in coming decades. In this study, we focused on an endemic cyprinid fish Cyprinion muscatense, as a model to investigate impacts of climate change on the mountain fishes inhibiting in this arid region. This species is expected to be strongly affected by climate change because of its limited distribution range in a montane area surrounded by lowlands and sea, limiting the species in shift to other areas. We used an ensemble approach by considering two regressions‐based species distribution modeling (SDM) algorithms: generalized linear models (GLM), and generalized additive models (GAM) to model the species habitat suitability and predict the impacts of climate change on the species habitat suitability. Based on the distribution models, the montane area located in northeastern Oman was identified as the most suitable habitat for this species. Our results indicate that, even under the minimum greenhouse gas emissions scenario (RCP 2.6), climate change will produce a high reduction in its potential future habitats. According to the results of percent contribution, elevation and annual minimum temperature were the most important variables in predicting the species suitable habitats. Results also showed that only a small percentage of suitable habitats for the species within boundaries of protected areas. Therefore, the impact of climate change on the species appears particularly alarming. Although our study was restricted to a single cyprinid freshwater species, decreases in potential habitats are likely predicted for other cyprinid fish species restricted to the mountains of this region, suggesting severe consideration is needed for aquatic systems in future conservation planning, especially for endemic freshwater fishes. [ABSTRACT FROM AUTHOR]

Understanding climate extremes and indices is crucial for addressing climate change impacts, including the increased variability in local weather patterns and extreme events. Previous studies on the Arabian Peninsula (AP) have been limited by sparse station data and restricted spatial coverage. To overcome this limitation, this paper aims to assess the spatial distribution and temporal trends of temperature and precipitation indices suggested by the Expert Team on Climate Change Detection and Indices (ETCCDI) using ERA5 reanalysis data from 1951 to 2020 for the AP. Additionally, this study investigated the changes relative to the reference period (1951–1980). The modified Mann-Kendall test and Sen's Slope estimator are utilized to detect significant trends and estimate their magnitude. Results revealed that ERA5 was consistent with previous studies that utilized in-situ station data, which offers a more detailed picture of the affected areas. The findings indicated a significant warming trend in temperature indices, with an increase of over 1 °C per decade observed across several areas, including the northern AP, and certain regions experiencing a discrepant change of 3 °C increase compared to the reference period. Changes in rainfall indices indicate a shift in rainfall patterns from the AP's fertile southwest regions towards more intense patterns in specific eastern regions, including Oman, Kuwait, Saudi Arabia, and Yemen. However, the precipitation temporal trends are weak in magnitude and variable spatially, with dominant decreases in both intensity (-10 mm per decade) and frequency indices (-5 days per decade). Some locations are subject to the combined effects of most heatwave indicators simultaneously, while flood indicators and yet others by drought indicators influence others. All these locations have been accurately identified in this study. The findings provide valuable information regarding the region's climate change vulnerability and adaptation needs. [Display omitted] • Prior studies relied on limited station data, short period, and MK trend test. • Extremes are assessed using ERA5, ETCCDI, Modified-MK, and Sen's Slope. • Affected areas are identified, and valuable insights for policymakers are set. • Significant warming trend: >1 °C/decade and > 2 °C change from reference period. • Spatiotemporal trends of precipitation are weak in magnitude and variable spatially. [ABSTRACT FROM AUTHOR]

The Arabian Gulf, one of the driest parts of the world, is already passing the water scarcity line as defined by the World Health Organization (WHO). The scarcity of renewable water resources and the growing discrepancy between demand and supply of water is a major challenge. Water scarcity is further worsened by rapidly growing demands due to rapid population growth, unsustainable consumption, climate change and weak management institutions and regulations. Water scarcity erodes the socio-economic sustainability of the communities that depend on the depleting storage. In this paper, an analysis of the water security situation within the Arabian Gulf region and the consequent socio-economic implications is presented. [ABSTRACT FROM AUTHOR]

It is essential to identify water sectors that will be significantly impacted by climate change and to develop strategies to enhance the resiliency of these sectors against climate change impacts. The Arabian Peninsula (AP) is an arid region facing increasingly more severe water-scarcity issues due to climate change impacts. We investigate abrupt changes in the AP's climate, and examined the spatial relationships between climatic changes, ENSO, and Indian Ocean Dipole (IOD). An analysis was conducted to examine how hydroclimatic changes impact the frequency of droughts in AP. The results show that AP is very sensitive to climate change impacts since 1990s. Regional climatic change hotspots in AP include an increase in geopotential height (GPH), surface temperature, potential evapotranspiration (PET), and a decrease in relative humidity, soil moisture, and rainfall between 1985 and 2020. The northern and northwestern areas of AP, specifically Hail, Al Qassim, Tabuk, and Al Jouf, experienced the most significant increases in GPH, warming, and PET. The meridional wind (zonal wind) speed has decreased (increased) between 1985 and 2020. Climate scenarios of CMIP6 of IPCC (Intergovernmental Panel of Climate Change) project future warmer and drier conditions over AP under significant warming and marginal increase in rainfall between 2020 and 2100. Furthermore, positive ENSO and IOD episodes are associated with negative rainfall and surface moisture anomalies, and positive surface temperature and PET anomalies over irrigated areas of AP. Climate warming in AP has also resulted in persistent drought conditions after 1998, which have significantly affected the agricultural sector of AP due to higher water demand for irrigated crops because of higher evaporation losses under climate warming. Therefore, representative estimations of regional water demand for irrigation in AP are essential in developing effective adaptation strategies against climate change impacts, such as introducing crop patterns of lower transpiration losses to achieve water saving and providing optimal irrigation water requirements for AP of arid climate. In conclusion, regions with limited water resources, such as the AP, will likely experience more significant water scarcity and drought. Therefore, identifying the water sectors most impacted by climate change and developing strategies to enhance their resiliency is essential. [ABSTRACT FROM AUTHOR]

Understanding past dynamics of upwelling cells is an important aspect of assessing potential upwelling changes in future climate change scenarios. Our present understanding of nutrient fluxes throughout the world's oceans emphasizes the importance of intermediate waters transporting nutrients from the Antarctic divergence into the middle and lower latitudes. These nutrient-rich waters fuel productivity within wind-driven upwelling cells in all major oceans. One such upwelling system is located along the Oman margin in the western Arabian Sea (WAS). Driven by cross-hemispheric winds, the WAS upwelling zone's intense productivity led to the formation of one of the most extensive oxygen minimum zones known today. In this study covering the Middle to Late Miocene at Ocean Drilling Program (ODP) Site 722, we investigate the inception of upwelling-derived primary productivity. This study presents new plankton assemblage data in the context of existing model- and data-based evidence constraining the tectonic and atmospheric boundary conditions for upwelling in the WAS. With this research, we build upon the original planktonic foraminifer-based research by Dick Kroon in 1991 as part of his research based on the ODP LEG 117. We show that monsoonal winds likely sustained upwelling since the emergence of the Arabian Peninsula after the Miocene Climatic Optimum (MCO) ∼ 14.7 Ma, with fully monsoonal conditions occurring since the end of the Middle Miocene Climatic Transition (MMCT) at ∼ 13 Ma. However, changing nutrient fluxes through Antarctic Intermediate and sub-Antarctic Mode Waters (AAIW/SAMW) were only established after ∼ 12 Ma. Rare occurrences of diatom frustules correspond to the maximum abundances of Reticulofenestra haqii and Reticulofenestra antarctica, indicating higher upwelling-derived nutrient levels. By 11 Ma, diatom abundance increases significantly, leading to alternating diatom blooms and high-nutrient-adapted nannoplankton taxa. These changes in primary producers are also well reflected in geochemical proxies with increasing δ15 N org. values (> 6 ‰) and high organic carbon accumulation. These proxies provide further independent evidence for high productivity and the onset of denitrification simultaneously. Our multi-proxy-based evaluation of Site 722 primary producers provides evidence for a stepwise evolution of Middle to Late Miocene productivity in the western Arabian Sea for the first time. The absence of a clear correlation with existing deep marine climate records suggests that both local wind patterns and intermediate water nutrient changes likely modulated productivity in the western Arabian Sea during the Middle to Late Miocene. Finally, we show that using a multi-proxy record provides novel insights into how plankton responded to changing nutrient conditions through time in a monsoon-wind-driven upwelling zone. [ABSTRACT FROM AUTHOR]

The early to mid-Holocene has long been recognised as a period of wetter climate with widespread lacustrine development and vegetation expansion throughout south-east Arabia. Recent palaeoclimate data has, however, transformed our understanding of the Holocene Pluvial Phase ( HPP) and evidence presented in this paper demonstrates that climate was neither homogeneous during the period, nor were shifts between pluvial and arid episodes synchronous across the region. This dynamic setting provided the backdrop for human expansion during the Neolithic, and in turn raises important questions about the interactions between these populations and the natural environment in south-east Arabia. [ABSTRACT FROM AUTHOR]

Abstract: Despite the present hyper-aridity, archaeological investigations in South-east Arabia have demonstrated that the region supported extensive human communities throughout the Neolithic and Bronze Age. These early populations utilised the region’s natural environment in a variety of ways, ranging from the exploitation of coastal resources to practicing pastoral and agrarian lifestyles in the interior. Palaeoclimate data suggests the corresponding period was characterised by considerable climatic variability yet, to date, few studies have attempted to investigate the relationship between climate, the environment and early human populations in the region. This paper combines new high-resolution palaeoclimate data from Awafi palaeolake, United Arab Emirates (UAE), with the region’s archaeological record from the Neolithic through to the onset of the Bronze Age. The evidence presented in this paper suggests that the environment of South-east Arabia offered different constraints and opportunities for early human occupation and subsistence. In particular, abrupt phases of aridity are demonstrated to have had a profound impact. Most notable is the change which occurred following the onset of climatic aridity at 5900 cal yr BP, when the region’s semi-nomadic, herder-gatherer populations abandoned much of the landscape and concentrated in selected environmental refugia, such as along the northern Omani coast. Human repopulation during the Bronze Age coincided with a return to more pluvial conditions under which a network of oasis agricultural settlements appeared along the piedmont zone of the northern Hajar Mountains. [Copyright &y& Elsevier]

The exhumation of actively deforming orogenic systems is commonly due to the incision of river systems in response to tectonically driven surface uplift. However, a regional base level and/or climatic variations can also cause erosional exhumation. The temporal and spatial distinction of the dominant mechanism during the topographic evolution of orogens is challenging. Using detailed morphological analyses and thermal modelling of an intrusive body through triple dating (zircon U–Pb, ZHe, and AHe), combined with the previously published structural, detrital, and bedrock low‐temperature thermochronometry (apatite fission track and apatite helium) analysis, the transition from early Oligocene (~27 Ma) and middle Miocene (~12 Ma) tectonic exhumation to late Miocene–early Pliocene (~7–5 Ma) river incision and erosional exhumation in the Talesh Mountains in the NW of the Arabia–Eurasia collision zone was documented. The late Miocene‐early Pliocene incision and the contemporaneous rapid exhumation documented in the Talesh Mountains are related to the base‐level fall of the Caspian Sea due to its isolation from the Paratethys domain. The effect of this base‐level fall then migrated to the margin of the Iranian Plateau and captured the overspilled basins (~4 Ma). [ABSTRACT FROM AUTHOR]

Rising global temperatures in the Arabian Peninsula region caused by climate change have increased the demand for air conditioning, resulting in more electricity consumption and CO 2 emissions. This paper treats Qatar as a representative country for understanding the effect of future regional warming on the electricity demand and CO 2 emissions We first develop a model that relates daily electricity demand with temperature. By combining this model with temperature projections from the CMIP6 database (bias adjusted and statistically downscaled) and population and GDP projections from four shared socioeconomic pathways (SSPs), we can calculate Qatar's demand for electricity until the end of the century. The model identifies an average sensitivity of +4.2%/°C for the electricity demand and projects an increase in electricity demand by 5–35% due to warming alone at the end of this century. The model suggests that under SSP1-2.6, warming-induced CO 2 emissions could be offset by carbon intensity improvements. Furthermore, under SSP5-8.5, assuming no carbon intensity improvement, future warming could add 20–35% of CO 2 emissions per year by the end of the century, with half of the electricity demand related to more frequent hot days. We further found that the temperature effect on power demand and CO 2 emissions is small compared to the effects from socioeconomic factors such as population, GDP, and carbon intensity. • Data-based model to predict electricity demand from daily temperature regionally. • Projection of power demand with CMIP6 temperature projections for different SSPs. • Inclusion of the effect of the evolution of the population and the GDP on the demand. • Assumption on the evolution of the carbon intensity to deduce the CO 2 emissions. • Application to Middle East countries and implication for global temperatures. [ABSTRACT FROM AUTHOR]

This study investigates sand and dust storms under RCP scenarios over the West Asia. The RegCM 4.7 was employed to simulate the dust event with non-hydrostatic core, a horizontal grid spacing of 20 km and 18 vertical sigma levels with the model top at 10 hPa. Data for running RegCM were extracted from the ICTP website and HadGEM2 database. The simulations were conducted for historical (1996–2005) and future (2021–2032) periods. The evaluation of HadGEM2 model using AERONET and MISR data revealed that the model could reproduce the aerosol features with a very high confidence. During the historical period, the AOD and DCB were strong in spring and summer with higher values mostly situated in Rab' al Khali desert of Arabian Peninsula, Red Sea, and the east of Dasht-e Lut. The atmospheric pattern at SLP and 850 hPa levels revealed that these regions are affected by strong dust outflows from the dipole in pressure between Indian-Pakistan low-pressure and high-pressure systems in the north of Africa and Caspian Sea plus cyclogenesis during dust storms. Also, the positive values of aerosol asymmetry parameter proved that aerosols in inland area are associated with dust outflows from the Rab' al Khali and the Dasht-e Lut deserts along with air pollution from industrial activities and the Sahara Desert dust in the coastal region. The future dust emission under RCP scenarios indicated that AOD and DCB values would diminish in all months especially in spring and the highest AOD would happen in the center and south of Arabian Peninsula, Red Sea, and southeast of Iran. Also, the dust emission flux would decrease in spring and increase in summer and fall as compared to present. The South Sinai and Arabian Peninsula would have the most frequent dust emission flux too, but the dust emission flux would significantly drop in the southeast of Iran. The results from RCPs also demonstrated that the wind speed mean would decrease and the mean of soil moisture increase by about 6–6.5 kg/m2 up to a depth of 10 cm in all RCP scenarios. [ABSTRACT FROM AUTHOR]

This paper examines the climate change impact on the spatiotemporal soil salinity dynamics during the last 30 years (1987–2017) in the arid landscape. The state of Kuwait, located at the northwest Arabian Peninsula, was selected as a pilot study area. To achieve this, a Landsat- Operational Land Imager (OLI) image acquired thereabouts simultaneously to a field survey was preprocessed and processed to derive a soil salinity map using a previously developed semi-empirical predictive model (SEPM). During the field survey, 100 geo-referenced soil samples were collected representing different soil salinity classes (non-saline, low, moderate, high, very high and extreme salinity). The laboratory analysis of soil samples was accomplished to measure the electrical conductivity (EC-Lab) to validate the selected and used SEPM. The results are statistically analyzed (p ˂ 0.05) to determine whether the differences are significant between the predicted salinity (EC-Predicted) and the measured ground truth (EC-Lab). Subsequently, the Landsat serial time's datasets acquired over the study area with the Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+) and OLI sensors during the last three decades over the intervals (1987, 1992, 1998, 2000, 2002, 2006, 2009, 2013, 2016 and 2017) were radiometrically calibrated. Likewise, the datasets were atmospherically and spectrally normalized by applying a semi-empirical line approach (SELA) based on the pseudo-invariant targets. Afterwards, a series of soil salinity maps were derived through the application of the SEPM on the images sequence. The trend of salinity changes was statistically tested according to climatic variables (temperatures and precipitations). The results revealed that the EC-Predicted validation display a best fits in comparison to the EC-Lab by indicating a good index of agreement (D = 0.84), an excellent correlation coefficient (R2 = 0.97) and low overall root mean square error (RMSE) (13%). This also demonstrates the validity of SEPM to be applicable to the other images acquired multi-temporally. For cross-calibration among the Landsat serial time's datasets, the SELA performed significantly with an RMSE ≤ ± 5% between all homologous spectral reflectances bands of the considered sensors. This accuracy is considered suitable and fits well the calibration standards of TM, ETM+ and OLI sensors for multi-temporal studies. Moreover, remarkable changes of soil salinity were observed in response to changes in climate that have warmed by more than 1.1 °C with a drastic decrease in precipitations during the last 30 years over the study area. Thus, salinized soils have expanded continuously in space and time and significantly correlated to precipitation rates (R2 = 0.73 and D = 0.85). [ABSTRACT FROM AUTHOR]

The summer monsoon rainfall affects most of the population of the Indian subcontinent. A slight variation of strength and spatial distribution in monsoon rains has huge societal impacts. So understanding the significance of its variability and the factors that control this variability is an imperative task. The Indian monsoon (also regarded as a global phenomenon) varies with the global climatic components like geopotential height, sea surface temperature, outgoing long-wave radiation and mean sea level pressure. The paper presents a statistical analysis of rainfall (over India) and climatic components (over the Arabian Peninsula) and the relationship between them. The period (1979–2013) shows a decrease in monsoon rainfall over the country. During this period, there was an increase in the tropospheric temperature over the Arabian Peninsula. Rainfall showed a direct relationship with the tropospheric temperature and thickness that gets stronger during the period (1979–2013). Except for the northeastern region of India, the rest showed a strong positive correlation with the middle and upper tropospheric temperature over the Arabian Peninsula while the lower tropospheric temperature showed a weak relationship. However, this correlation gets weakened during the El Nino and La Nina years. The findings will be helpful to enhance the Indian rainfall variation and the climatic factors responsible for this variation. [ABSTRACT FROM AUTHOR]

We investigate long-term changes in winter rainfall patterns across the Arabian Peninsula (AP) through an analysis of the Climate Research Unit (CRU) gridded rainfall dataset, and long-term rainfall measurements collected at 39 stations distributed across the AP over the period 1951–2010. We reveal a long-term increase in winter rainfall of about 25–30% over the eastern AP and a long-term decrease of about 10–20% in the southern and northeastern AP. A partial correlation analysis suggests that canonical El Niños are associated with significant negative winter rainfall anomalies in the southern and southwest AP during the 1951–1980 period. However, the extent of the El Niño-induced rainfall deficit decreased in subsequent decades. In fact, a significant above-average rainfall occurs in recent decades over Ethiopia, southwest Yemen and central AP during canonical El Niños. Furthermore, positive phases of the Indian Ocean basin mode (IOBM), which lags the canonical ENSO signal by 3–4 months, are linked with significant below-average winter rainfall over the central and northern AP, but only until the 1970 s. We investigated the teleconnections between the variability of AP winter rainfall and various atmospheric parameters from the European Centre for Medium Range Weather Forecasting (ECMWF) twentieth century (ERA-20C) reanalysis. Notably, sub-tropical westerly jet (STJ) shifted southward and intensified over the AP during recent decades. This shift of the STJ favoured an increase in the frequent passage of transients, which contributed to increased winter rainfall over AP. These events anomalously strengthen the upper level westerlies during El Niño Modokis, adding to the recently-strengthened STJ over the AP, thereby further intensifying the transient activity. This large-scale background change likely weakened the impact of canonical El Niño and the IOBM events. [ABSTRACT FROM AUTHOR]

Current seawater temperatures around the northeastern Arabian Peninsula resemble future global forecasts as temperatures > 35 °C are commonly observed in summer. To provide a more fundamental aim of understanding the structure of wild populations in extreme environmental conditions, we conducted a population genetic study of a widespread, regional endemic table coral species, Acropora downingi, across the northeastern Arabian Peninsula. A total of 63 samples were collected in the southern Arabian/Persian Gulf (Abu Dhabi and Qatar) and the Sea of Oman (northeastern Oman). Using RAD-seq techniques, we described the population structure of A. downingi across the study area. Pairwise G'st and distance-based analyses using neutral markers displayed two distinct genetic clusters: one represented by Arabian/Persian Gulf individuals, and the other by Sea of Oman individuals. Nevertheless, a model-based method applied to the genetic data suggested a panmictic population encompassing both seas. Hypotheses to explain the distinctiveness of phylogeographic subregions in the northeastern Arabian Peninsula rely on either (1) bottleneck events due to successive mass coral bleaching, (2) recent founder effect, (3) ecological speciation due to the large spatial gradients in physical conditions, or (4) the combination of seascape features, ocean circulation and larval traits. Neutral markers indicated a slightly structured population of A. downingi, which exclude the ecological speciation hypothesis. Future studies across a broader range of organisms are required to furnish evidence for existing hypotheses explaining a population structure observed in the study area. Though this is the most thermally tolerant acroporid species worldwide, A. downingi corals in the Arabian/Persian Gulf have undergone major mortality events over the past three decades. Therefore, the present genetic study has important implications for understanding patterns and processes of differentiation in this group, whose populations may be pushed to extinction as the Arabian/Persian Gulf warms. [ABSTRACT FROM AUTHOR]

Precipitation extremes will generally intensify in response to a warming climate. This robust fingerprint of climate change is of particular concern, resulting in heavy rainfall and devastating floods. Often this intensification is explained as a consequence of the Clausius–Clapeyron law in a warmer world, under constant relative humidity. Here, based on an ensemble of CMIP5 global climate models and high-resolution regional climate simulations, we take the example of Southwest Asia, where extreme storms will intensify beyond the Clausius- Clapeyron scaling, and propose an additional novel mechanism for this region: the unique increase in atmospheric relative humidity over the Arabian Sea and associated deep northward penetration of moisture. This increase in humidity is dictated by changes in circulation over the Indian Ocean. Our proposed mechanism is consistent with the recent, most extreme storm ever observed in the region. Our findings advance a new understanding of natural climate variability in this region, with substantial implications for climate change adaptation of the region's critical infrastructure. [ABSTRACT FROM AUTHOR]

Changing climatic conditions are thought to be a major control of human presence in Arabia during the Paleolithic. Whilst the Pleistocene archaeological record shows that periods of increased monsoon rainfall attracted human occupation and led to increased population densities, the impact of arid conditions on human populations in Arabia remains largely speculative. Here, we present data from Jebel Faya in Southeast (SE) Arabia, which document four periods of human occupation between c. 210,000 and 120,000 years ago. The Jebel Faya record indicates that human occupation of SE Arabia was more regular and not exclusively linked to major humid periods. Our data show that brief phases of increased rainfall additionally enabled human settlement in the Faya region. These results imply that the mosaic environments in SE Arabia have likely formed a population refugia at the end of the Middle and the beginning of the Late Pleistocene. [ABSTRACT FROM AUTHOR]

Mesoscale Convective Systems (MCSs) over the southern Arabian Peninsula are more common during the spring months of March and April. In this paper, the processes behind such severe convective events and their local-scale impacts are investigated using reanalysis data, satellite-derived and observational products. The analysis of 95 MCS events from 2000 to 2020 revealed that they are triggered by low-level wind convergence and moisture advection from the Arabian Sea, Arabian Gulf and/or Red Sea. An equatorward displacement and strengthening of the subtropical jet also precondition the environment, as does the presence of a mid-level trough. The latter is generally part of a large-scale pattern of anomalies that are equivalent barotropic in nature, and therefore likely a response to tropical or subtropical forcing. At more local-scale, a drying of the mid-troposphere between 850 and 250 hPa typically by 50%, a reduction of the upper-level winds by about 5 m s−1, and an increase in the upper-tropospheric temperature on average by 2–3 K, are typically observed during MCS events. Over the 21-year period, a statistically significant increase in the MCSs' duration over southeast Arabian Peninsula has been found, suggesting that such extreme events may be even more impactful in a warming world. • MCSs over the southern Arabian Peninsula occur more frequently in March and April months. • Preconditioning and triggering processes for MCSs over this region are investigated. • Over the 20-year period, MCSs have been lasting longer over the UAE. [ABSTRACT FROM AUTHOR]

We present shipborne measurements of NO x (≡ NO + NO 2) and NO y (≡ NO x+ gas- and particle-phase organic and inorganic oxides of nitrogen) in summer 2017 as part of the expedition "Air Quality and climate change in the Arabian BAsin" (AQABA). The NO x and NO z (≡ NO y -NO x) measurements, made with a thermal dissociation cavity ring-down spectrometer (TD-CRDS), were used to examine the chemical mechanisms involved in the processing of primary NO x emissions and their influence on the NO y budget in chemically distinct marine environments, including the Mediterranean Sea, the Red Sea, and the Arabian Gulf, which were influenced to varying extents by emissions from shipping and oil and gas production. Complementing the TD-CRDS measurements, NO and NO 2 data sets from a chemiluminescence detector (CLD) were used in the analysis. In all regions, we find that NO x is strongly connected to ship emissions, both via direct emission of NO and via the formation of HONO and its subsequent photolytic conversion to NO. The role of HONO was assessed by calculating the NO x production rate from its photolysis. Mean NO 2 lifetimes were 3.9 h in the Mediterranean Sea, 4.0 h in the Arabian Gulf, and 5.0 h in the Red Sea area. The cumulative loss of NO 2 during the night (reaction with O 3) was more important than daytime losses (reaction with OH) over the Arabian Gulf (by a factor 2.8) and over the Red Sea (factor 2.9), whereas over the Mediterranean Sea, where OH levels were high, daytime losses dominated (factor 2.5). Regional ozone production efficiencies (OPEs; calculated from the correlation between O x and NO z , where O x= O 3+ NO 2) ranged from 10.5 ± 0.9 to 19.1 ± 1.1. This metric quantifies the relative strength of photochemical O 3 production from NO x compared to the competing sequestering into NO z species. The largest values were found over the Arabian Gulf, consistent with high levels of O 3 found in that region (10–90 percentiles range: 23–108 ppbv). The fractional contribution of individual NO z species to NO y exhibited a large regional variability, with HNO 3 generally the dominant component (on average 33 % of NO y) with significant contributions from organic nitrates (11 %) and particulate nitrates in the PM 1 size range (8 %). [ABSTRACT FROM AUTHOR]

The current research is devoted to highlight the past, present and future status of groundwater characteristics over the Arabian Peninsula (AP) and west region of Iraq. The Umm er Radhuma, Rus Dammam and Neogene deposits are the major hydrostratigraphic units supplying the main groundwater resources in the AP. Water shortage is still a major problem for many countries in the world, including oil-producing countries such as Iraq, Saudi Arabia (SA), the United Arab Emirates (UAE), Qatar, Oman and Bahrain. The withdrawal of groundwater has been reflected in salinization of agricultural soils, leading to an increase in high-cost technologies such as desalination of seawater to provide suitable water for diverse sectors. Hence, the use of seawater desalination as a major source of water is unavoidable, and country development requires the use of renewable energy as protection of the environment. The need to conserve and use groundwater resources efficiently is highly essential owing to the fact that it is the only natural source of water in such developing countries of global importance. The review comprises various essential components related to groundwater variability including the hydrogeological aspects, climate change, drawdown and abstraction, rainwater harvesting, desertification and population increment. Based on the reviewed perspectives, various practical visions are discussed for better groundwater management and sustainability. This research is presented as a milestone for diverse future works and investigation that might be conducted for better water resources management over the AP region. [ABSTRACT FROM AUTHOR]

Available water resources in the Middle East, as one of the most water-scarce regions of the world, have undergone extra pressure due to climatic change, population growth, and economic development during the past decades. The objective of this study is to detect the trends and quantify the changes in aridity with respect to precipitation and potential evapotranspiration in 20 countries of the Middle East and the adjacent area. A pixel-wise trend analysis was conducted on precipitation, potential evapotranspiration, and the aridity index for 71 years from 1948 to 2018. Results showed a statistically significant (|Z| > 1.96) increase up to 106% in aridity (a downward trend in the aridity index) from December to September in most parts of the region. Aridity in October and November had a downward tendency in most parts of the study area. At an annual time scale, 62.5% of the detected trends in aridity were found to be upward (up to 96% increase) due to the combined effects of the decrease in precipitation and the increase in potential evapotranspiration. Annual aridity was found to be downward in 37.5% of the detected trends (up to 61% decrease). The highest and the lowest trends in aridity were found in the north of Sudan (96%) and eastern Arabia (− 61%). [ABSTRACT FROM AUTHOR]

Over the past decade, a growing interest has developed on the archaeology, palaeontology, and palaeoenvironments of the Arabian Peninsula. It is now clear that hominins repeatedly dispersed into Arabia, notably during pluvial interglacial periods when much of the peninsula was characterised by a semiarid grassland environment. During the intervening glacial phases, however, grasslands were replaced with arid and hyperarid deserts. These millennial-scale climatic fluctuations have subjected bones and fossils to a dramatic suite of environmental conditions, affecting their fossilisation and preservation. Yet, as relatively few palaeontological assemblages have been reported from the Pleistocene of Arabia, our understanding of the preservational pathways that skeletal elements can take in these types of environments is lacking. Here, we report the first widespread taxonomic and taphonomic assessment of Arabian fossil deposits. Novel fossil fauna are described and overall the fauna are consistent with a well-watered semiarid grassland environment. Likewise, the taphonomic results suggest that bones were deposited under more humid conditions than present in the region today. However, fossils often exhibit significant attrition, obscuring and fragmenting most finds. These are likely tied to wind abrasion, insolation, and salt weathering following fossilisation and exhumation, processes particularly prevalent in desert environments. [ABSTRACT FROM AUTHOR]

The changes in the El Niño–Southern Oscillation (ENSO) phenomenon and its precipitation-related teleconnections over the globe under climate change are investigated in the Community Earth System Model Large Ensemble from 1950 to 2100. For the investigation, a recently developed ensemble-based method, the snapshot empirical orthogonal function (SEOF) analysis, is used. The instantaneous ENSO pattern is defined as the leading mode of the SEOF analysis carried out at a given time instant over the ensemble. The corresponding principal components (PC1s) characterize the ENSO phases. By considering sea surface temperature (SST) regression maps, we find that the largest changes in the typical amplitude of SST fluctuations occur in the June–July–August–September (JJAS) season, in the Niño3–Niño3.4 (5 ∘ N–5 ∘ S, 170–90 ∘ W; NOAA Climate Prediction Center) region, and the western part of the Pacific Ocean; however, the increase is also considerable along the Equator in December–January–February (DJF). The Niño3 amplitude also shows an increase of about 20 % and 10 % in JJAS and DJF, respectively. The strength of the precipitation-related teleconnections of the ENSO is found to be nonstationary, as well. For example, the anticorrelation with precipitation in Australia in JJAS and the positive correlation in central and northern Africa in DJF are predicted to be more pronounced by the end of the 21th century. Half-year-lagged correlations, aiming to predict precipitation conditions from ENSO phases, are also studied. The Australian and Indonesian precipitation and that of the eastern part of Africa in both JJAS and DJF seem to be well predictable based on the ENSO phase, while the southern Indian precipitation relates to the half-year previous ENSO phase only in DJF. The strength of these connections increases, especially from the African region to the Arabian Peninsula. [ABSTRACT FROM AUTHOR]

Regional Climate Models (RCMs) are increasingly used to add small-scale processes at higher grid resolution that are not represented by their Lateral Boundary Conditions (LBCs). Rossby Centre regional atmospheric model, RCA4, has downscaled three Global Climate Models (GCMs), namely, CNRM-CM5, EC-EARTH and GFDL-ESM2M in the COordinated Regional climate Downscaling EXperiment (CORDEX) framework for Middle East North Africa (MENA) and South Asia (SA) domains. Arabian Peninsula is covered in both MENA and SA simulations, which gives a unique opportunity to study the effects of CORDEX domain and LBCs on the simulation of temperature and precipitation by RCM. It is examined by calculating the differences between MENA and SA simulations for different driving GCMs in the historical (1976–2005) and future (2071–2100) periods under RCP8.5 emission scenario, for both summer (dry) and winter (wet) seasons. RCA4 performs generally well when simulating the observed temperature and precipitation patterns, with some local wet biases over Asir Mountains and cold bias over the north eastern parts of Saudi Arabia. The simulations of temperature seem to be very sensitive to the simulation domain (i.e., MENA and SA) and less sensitive to different LBCs, whereas in case of precipitation LBCs seems to play a dominant role. The MENA simulations generally project about 2 °C warmer and drier climate compared to SA simulations by the end of this century, which is comparable to the differences arising due to different LBCs and climate change. [ABSTRACT FROM AUTHOR]

Major global events during the Oligocene epoch included a climatic change from warm "greenhouse" to a cooler "icehouse" that was accompanied by the onset of Antarctic glaciation. These events led to decline in water temperature, salinity, nutrient supply and oxygen levels, and the extinction of some major fauna and flora. Within the study area, during this epoch, the shrinkage of the Neotethys and the development of the Paratethys, the collision of Arabia with Eurasia and the development of the Zagros mountains and opening of the Red Sea which led eventually to the separation of Arabia from Africa were witnessed. Oligocene sediments are absent from most parts of the Arabian Plate but are well-preserved in western and southwestern Iran. The most well-developed strata are the coral reefs of the Kirkuk Group in northern Iraq and the shallow water carbonates of the Asmari Formation in southwestern Iran. The study area also represents the birthplace of commercial hydrocarbons production in the Middle East from these sediments in Masjid-i-Sulaiman Field in Iran and Kirkuk Field in Iraq at the first decade of the last century. Future exploration for hydrocarbons potential should focus on identifying subsurface coral buildups or clastic strata that are equivalent to the Asmari Formation in Iran. [ABSTRACT FROM AUTHOR]

Climate change is known as one of the key challenges of the 21st century for sustainable agricultural development over Southwest Asia. However, not much is known about the way that climate changes might affect precipitation, temperature, and climate zones as their consequence over Southwest Asia. Here we have analysed probable changes in modified Thornthwaite climate zones by using monthly temperature and precipitation data from 320 meteorological stations during the historical period of 1971–2015, as well as the future projections of 17 GCMs (General Circulation Models) outputs under the RCP4.5 and RCP8.5 scenarios in two future periods, 2041–2070 and 2071–2100. The CMIP5 climate projections were bias corrected using the correction factors derived in the historical period and applied to simulate future climatic conditions over Southwest Asia. Results derived from multi model ensemble projections of precipitation and temperature indicated that the regional mean annual temperature by the future period of 2071–2100 is expected to increase by 2.4 and 3.8°C, under RCP4.5 and RCP8.5, respectively. Also, except for the southern and eastern parts of the Arabian Peninsula, by 2071–2100, the mean annual precipitation would significantly decrease by on average 6.2 and 7.5%, under RCP4.5 and RCP8.5, respectively. Computing climate types based on averages from three climatic periods (1971–2015, 2041–2070, and 2071–2100) showed that Southwest Asia tends to become warmer and dryer. For example, by the end of the 21st century, the percentage of the area occupied by the torrid‐arid climate type (which already covers 13.8% of the total area) would be 29.3 and 36.4% under RCP4.5 and RCP8.5, respectively. These changes are important because they would definitely have profound ecological, hydrologic, and social consequences and may affect the basic components of sustainable agricultural systems like crop and livestock productions. [ABSTRACT FROM AUTHOR]

Oases are subject to decreasing resources and changing human activities. Fully aware of their rich heritage, the United Arab Emirates (UAE) have undertaken work to preserve and revitalize these oases. However, there is a clear lack of understanding of the dynamic links between climate change, hydraulic and agricultural management, and socioeconomic activities. To clarify these links, our team conducted a systematic geoarchaeological, geophysical, spatial, and chronological study of the Masafi oasis, UAE. Results indicate the existence of a natural humid area as early as the late Pleistocene (~18 cal ka BP). These conditions persist during the early-mid Holocene with drainage activation and soil development (~12–6.3 ka). During the late Holocene, after the emergence of the "artificial" oasis around ~3250 cal yr BP, cycles of intense management suggesting water availability (~3250–2380 cal yr BP; 550 cal yr BP) alternate with episodes of fluvial detritism (~2380–1870 cal yr BP; >550 cal yr BP) and scattered evidence of farming activities with complex hydroclimatic signatures (~2300–550 cal yr BP). These results, together with regional environmental data, indicate that water and soil resources were available and exploited strategically throughout the Holocene despite adverse climatic conditions, and the oasis of Masafi could have acted as a desert refugium. [ABSTRACT FROM AUTHOR]

Aims: To explore whether wide‐ranging, generalist primates like baboons can be presumed 'resilient' in the face of climate change. We identify environmental variables influencing baboons' current distributions and predict their future potential distributions under different climate change scenarios. Location: Africa and Arabia. Taxon: Baboons, Papio spp. Methods: We used localities for olive, yellow, Guinea, hamadryas, chacma and Kinda baboons together with high‐resolution data on bioclimatic variables, altitude and vegetation to construct species distribution models (SDMs). These SDMs were run under current and future conditions, with future models based on three General Circulation Models (MIROC‐ESM, CCSM4 and HadGEM2‐ES) under two Representative Concentration Pathways (RCP2.6 and RCP6.0) for 2050 and 2070 to explore a range of different possible futures. Results: All SDMs produced AUC values >0.916 suggesting excellent overall performance. Altitude was the most important variable influencing Guinea baboon distributions (contributing 41.6%), temperature seasonality for olive and yellow baboons (47.5% and 35.4% respectively), precipitation of the driest month for hamadryas baboons (24.4%), annual mean precipitation for the Kinda baboon (45.1%) and mean temperature of the driest quarter for chacma baboons (41.4%). Chacma and Kinda baboons are predicted to suffer substantial habitat loss, and Guinea baboons may do the same if conditions aridify as climates warm. In contrast, all models for the olive and hamadryas baboons predicted an increase in suitable habitat and only smaller changes were predicted for the yellow baboon. Main Conclusions: Two or three of six baboon taxa are at risk of significant habitat loss as climates warm despite their apparent ecological flexibility. The chacma and Kinda baboons (both IUCN listed as Least Concern) will be worst affected, followed by the Guinea baboon (Near Threatened) if warming brings aridification. We recommend more focus on biogeographical tools as a means of exploring vulnerabilities in seemingly resilient species. [ABSTRACT FROM AUTHOR]

The climate variability on Earth is strongly influenced by the changes in the Sea Surface Temperature (SST) anomalies in the tropical oceans. More specifically, the inter-annual climate variability in the tropics as well as extra-tropical areas has large impact due to the anomalous SSTs in the tropical Pacific coupled with the El Niño Southern Oscillation (ENSO) through atmospheric teleconnections. However, the effect of ENSO on Middle Eastern region, specifically the Arabian Peninsula (AP) is marginally explored in previous studies. Hence, this study explicitly focuses on the assessment of ENSO variability and its winter climate teleconnections to the AP using the Community Atmospheric Model Version 4.0 (CAM4) simulations and Reanalysis datasets. ENSO teleconnections are also evaluated based on two sensitivity experiments (ENSO-related and ENSO-unrelated) using the CAM4 model. It is observed that during El Niño years the peninsular region receives more rainfall through enhanced moisture transport associated with anomalous westerly winds from adjoining Seas. The Rossby wave energy propagation in the atmosphere underlies important teleconnections involving ENSO. It is also noticed that there exist a distinct change in the phase of the Rossby wave pattern during El Niño and La Niña years which further causes the shift in the position of the jet stream over the Middle East. [ABSTRACT FROM AUTHOR]

This study presents an assessment of global climate model (GCM) performances for the regions Arabian Peninsula, Brazil and Ukraine, all facing problems related to water availability as well as quality and so are the focus regions for investigations within the Integrated Water Resources Management Project 'International Water Research Alliance Saxony'. Results from the model performance assessment have been applied to derive estimates of the future climate in the regions by means of ensemble averaging. The study uses GCM data from the third Climate Model Intercomparison Project. Model performances were assessed by the Model Performance Index (MPI) as well as Taylor diagrams applying different reference data sets like reanalysis data as well as observational data sets. The model performances were analysed for different domain sizes. Climate variables of different tropospheric levels were classified by applying projections of the overall model ensemble as well as projections of a subset of models (selected according to the MPI) in variables with different levels of certainty of change. The MPI as well as the reliability ensemble averaging method were employed to calculate ensemble averages for variables with high certainties of change. Results are presented for mean values within the time periods 2040-2060 an 2080-2100. Applying different data sets as reference data shows that model performance crucially depends on the reference data set. The size of the model domain is of minor importance. Model rankings vary between regions. Certain changes are found for temperatures and geopotential heights in all levels but, e.g., not for precipitation. [ABSTRACT FROM AUTHOR]

ABSTRACT This article presents an analysis of observed climate extremes over the Arabian Peninsula ( AP); a region for which little such analysis has been available. A set of climate extremes indices developed by the Expert Team on Climate Change Detection and Indices ( ETCCDI) were computed and analysed for trends including the periods 1970-2008 and 1986-2008 at 23 stations covering six countries (Bahrain, Qatar, Kuwait, Oman, Saudi Arabia and UAE) and for Bahrain (1950-2008), Kuwait (1962-2008), Masirah and Salalah (1943-2008). The results indicate a general decreasing trend of cold temperature extremes and increasing trends of the warm temperature extremes during the periods of analysis. Over the whole region, a remarkable and highly significant increase in very warm nights during 1986-2008 has occurred. In general higher temperature trends (magnitudes/significance) are reported over the northern AP in the day-time extremes while for the night-time extremes the trends are higher and significant for the southern region especially during the recent decades. The precipitation indices trends are weak and insignificant except for the annual count of days when precipitation exceeds 10 mm which shows a significant decrease during 1986-2008. [ABSTRACT FROM AUTHOR]

We investigate the dust radiative forcing and its feedback on the Arabian Peninsula's wet season climate using the International Centre for Theoretical Physics-Regional Climate Model (ICTP-RegCM4). We have found that the dust plumes exert a negative (positive) radiative forcing at the surface (top of the atmosphere) by reducing incoming solar radiation reaching the ground and locally heating up the atmosphere column. Consequently, the surface air temperature is cooler, hence indicating a decrease in the warm bias and an increase in the temperature gradient. This reduces the geopotential heights and enhances the low-level wind convergence, suggesting stronger upward motion. These changes increase evaporation, the difference between precipitation and evaporation in the atmosphere and rainfall over the Peninsula, indicating an intensification of the hydrologic cycle. The decrease in the precipitation dry bias and the large reduction in the temperature warm bias caused by the impact of dust over the entire Peninsula represent a significant success for the RegCM4 simulation. Therefore, the inclusion of dust in the simulation of the Arabian Peninsula's climate for the wet season contributes to an improved performance of this regional climate model over the region. [ABSTRACT FROM AUTHOR]

The climate of the Arabian Peninsula is characterized by significant spatial and temporal variations, due to its complex topography and the large-scale atmospheric circulation. Furthermore, the role of dust in the formation of regional climate is considered to be crucial. In this work, the regional climatology for the Arabian Peninsula has been studied by employing a high resolution state of the art atmospheric model that included sophisticated physical parameterization schemes and online treatment of natural aerosol particles. The simulations covered a 30-year period (1986–2015) with a temporal resolution of 3 h and a spatial distance of 9 km. The main focus was given to the spatial and temporal variations of mean temperature and temperature extremes, wind speed and direction, and relative humidity. The results were evaluated using in situ measurements indicating a good agreement. An examination of possible climatic changes during the present climate was also performed through a comprehensive analysis of the trends of mean temperature and temperature extremes. The statistical significant trend values were overall positive and increased over the northwestern parts of the examined area. Similar spatial distributions were found for the daily minimum and maximum temperatures. Higher positive values emerged for the daily maxima. [ABSTRACT FROM AUTHOR]

In 1917, T. E. Lawrence recorded his experience of the passage of a dust storm, or haboob, while travelling in Hejaz in Arabia. The account was published that year in The Arab Bulletin, an intelligence journal. The description of this encounter is vivid, and it is sufficiently detailed that it allows comparison with more recent scientific investigations of the phenomena described. These storms are still subjects of research, which is aimed at improving representation of their weather- and climate-related effects. [ABSTRACT FROM AUTHOR]