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The Middle East and North Africa (MENA) region has experienced more frequent and severe drought events in recent decades, leading to increasingly pressing concerns over already strained food and water security. An effective drought monitoring and early warning system is thus critical to support risk mitigation and management by countries in the region. Here we investigate the potential for assimilation of leaf area index (LAI) and soil moisture observations to improve the representation of the overall hydrological and carbon cycles and drought by an advanced land surface model. The results reveal that assimilating soil moisture does not meaningfully improve model representation of the hydrological and biospheric processes for this region, but instead it degrades the simulation of the interannual variation in evapotranspiration (ET) and carbon fluxes, mainly due to model weaknesses in representing prognostic phenology. However, assimilating LAI leads to greater improvement, especially for transpiration and carbon fluxes, by constraining the timing of simulated vegetation growth response to evolving climate conditions. LAI assimilation also helps to correct for the erroneous interaction between the prognostic phenology and irrigation during summertime, effectively reducing a large positive bias in ET and carbon fluxes. Independently assimilating LAI or soil moisture alters the categorization of drought, with the differences being greater for more severe drought categories. We highlight the vegetation representation in response to changing land use and hydroclimate as one of the key processes to be captured for building a successful drought early warning system for the MENA region. [ABSTRACT FROM AUTHOR]

The Middle East is one of the world's most vulnerable areas to climate change, which has exacerbated environmental, agricultural, water conflict, and public health issues in the region. Here we analyze the latest climate model projections of precipitation and temperature for the very high emissions scenario, SSP5‐8.5, to detect potential future changes in this region. A baseline period (1981–2010) is compared with the middle (2040–2069) and end (2070–2099) of the 21st century. The results, representing the worst‐case scenario, identify the Tigris‐Euphrates headwaters as the hotspot of future compounding effects of climate change in the Middle East. Those effects result from the coincidence of elevated temperature, reduced precipitation, and enhanced interannual variability of precipitation. The hotspot overlays the location of the Southeastern Anatolia Project (in Turkish, Güneydoğu Anadolu Projesi [GAP]) irrigation initiative. In this climate context, risks to GAP viability and downstream water security, and associated potential for water‐related conflicts and migration are considerable and demand a reconsideration of the risk‐benefit assessment of GAP. This need has become more urgent after the recent widespread and deadly climate‐related conflicts and wildfires in summer 2021 across the Middle East that further underlined vulnerability of the region to climate extremes. Plain Language Summary: The Middle East, one of the world's most vulnerable regions to climate change, has experienced a growing number of severe extreme events in recent decades. These events not only have imposed lasting socio‐environmental impacts locally but have contributed to transboundary water issues with implications for regional and global security. Climate model projections show that the adverse effects of such events will likely be exacerbated over downstream countries of the Tigris‐Euphrates basin in coming decades. This conclusion is drawn because concurrent extreme hot and dry conditions and enhanced precipitation variability are projected over the Tigris‐Euphrates headwaters, where the Southeastern Anatolia Project (in Turkish, Güneydoğu Anadolu Projesi [GAP]) is located. As a result, the negative impacts of GAP may outnumber its benefits, and this study attempts to warn decision‐makers of the urgent need to integrate these trends to water resource planning and international negotiations. Key Points: The Tigris‐Euphrates headwaters is identified as the hotspot of future compound effects of climate change in the Middle EastThe adverse impacts of the Southeastern Anatolia Project (in Turkish, Güneydoğu Anadolu Projesi [GAP]) may outnumber its benefits in coming decadesGAP may exacerbate environmental, agricultural, water conflict, and public health issues in the region [ABSTRACT FROM AUTHOR]

Many regions in Africa and the Middle East are vulnerable to drought and to water and food insecurity, motivating agency efforts such as the U.S. Agency for International Development's (USAID) Famine Early Warning Systems Network (FEWS NET) to provide early warning of drought events in the region. Each year these warnings guide life-saving assistance that reaches millions of people. A new NASA multimodel, remote sensing-based hydrological forecasting and analysis system, NHyFAS, has been developed to support such efforts by improving the FEWS NET's current early warning capabilities. NHyFAS derives its skill from two sources: (i) accurate initial conditions, as produced by an offline land modeling system through the application and/or assimilation of various satellite data (precipitation, soil moisture, and terrestrial water storage), and (ii) meteorological forcing data during the forecast period as produced by a state-of-the-art ocean-land-atmosphere forecast system. The land modeling framework used is the Land Information System (LIS), which employs a suite of land surface models, allowing multimodel ensembles and multiple data assimilation strategies to better estimate land surface conditions. An evaluation of NHyFAS shows that its 1-5-month hindcasts successfully capture known historic drought events, and it has improved skill over benchmark-type hindcasts. The system also benefits from strong collaboration with end-user partners in Africa and the Middle East, who provide insights on strategies to formulate and communicate early warning indicators to water and food security communities. The additional lead time provided by this system will increase the speed, accuracy, and efficacy of humanitarian disaster relief, helping to save lives and livelihoods. [ABSTRACT FROM AUTHOR]

The Euphrates Plain (EP) experiences large interannual variability in vegetation cover, especially in areas of marginal rain-fed agriculture. Vegetation in this region is primarily limited by available soil moisture, as determined by winter precipitation, spring precipitation, and air temperature. Satellite analyses indicate that the springtime normalized difference vegetation index (NDVI) is negatively correlated with surface albedo, and that interannual variability in albedo in the EP produces an estimated forcing on the radiation balance that peaks at 16.0 W m-2 in May. Simulations with a regional climate model indicate that surface energy fluxes during a drought year (1999) differed substantially from those during a year with normal precipitation (2003). These differences were geographically specific, with the EP exhibiting increased albedo and decreased sensible heat flux while the neighboring Zagros Plateau region showed no albedo effect, a large increase in sensible heat flux, and an offsetting reduction in latent heat flux. In both the EP and the Zagros there was a potential for positive feedbacks on temperature and drought in late spring, though the most likely feedback mechanisms differed between the two regions: in the EP surface brightening leads to cooling and reduced turbulent heat flux, while in the Zagros region reduced latent heat flux leads to warming and a deepening of the planetary boundary layer. [ABSTRACT FROM AUTHOR]

Several studies have linked high temperatures to increases in violent conflicts. The findings are controversial, however, as there has been no systematic cross-sectional analysis performed to demonstrate the generality of the proposed relationship. Moreover, the timescale of temperature/violence relationships have not been fully investigated; it is unclear how short versus long-term, or seasonal and inter-annual temperature variability contribute to the likelihood or frequency of violent events. We here perform systematic regional and grid-based longitudinal analyses in Africa and the Middle East for the period 1990–2017, using geolocated information on armed conflicts and a recently released satellite-based gridded temperature data set. We find seasonal synchrony between temperature and number of armed conflicts at the regional scale (climatic region), as well as a positive relationship in temperature and conflict anomalies on inter-annual timescales at the grid cell level (for the entire African and ME region). After controlling for 'location effects', we do not find that long-term warming has affected armed conflicts for the last three decades. However, the effects of temperature anomalies are stronger in warmer places (~5% increase per 10 °C, P < 0.05), suggesting that populations living in warmer places are more sensitive to temperature deviations. Taken together, these findings imply that projected warming and increasing temperature variability may enhance violence in these regions, though the mechanisms of the relationships still need to be exposed. [ABSTRACT FROM AUTHOR]