Recent atmospheric changes and future projections along the Saudi Arabian Red Sea Coast

Recent and future climate diagrams (surface air temperature, surface relative humidity, surface wind, and mean sea level pressure) for the Saudi Arabian Red Sea Coast are analysed based on hourly observations (2016–2020) and hourly ERA5 data (1979–2020) with daily GFDL mini-ensemble means (2006–2100). Moreover, GFDL mini-ensemble means are calculated based on the results of three GFDL simulations (GFDL-CM3, GFDL-ESM2M, and GFDL-ESM2G). Observation data are employed to describe the short-term current weather variability. However, ERA5 data are considered to study the long-term current weather variability after bias removal via a comparison to observations. Finally, a bias correction statistical model was developed by matching the cumulative distribution functions (CDFs) of corrected ERA5 and mini-ensemble mean data over 15 years (2006–2020). The obtained local statistic were used to statically downscale GFDL mini-ensemble means to study the future uncertainty in the atmospheric parameters studied. There occurred significant spatial variability across the study area, especially regarding the surface air temperature and relative humidity, based on monthly analysis of both observation and ERA5 data. Moreover, the results indicated that the ERA5 data suitably describe Tabuk, Jeddah and Jizan weather conditions with a marked spatial variability. The best performance of ERA5 surface air temperature and relative humidity (surface wind speed and sea level pressure) data was detected in Tabuk (Jeddah). These data for the Saudi Arabian Red Sea coast, 1979–2020, exhibit significant positive trends of the surface air temperature and surface wind speed and significant negative trends of the relative humidity and sea level pressure. The GFDL mini-ensemble mean projection result, up to 2100, contains a significant bias in the studied weather parameters. This is partly attributed to the coarse GFDL resolution (2° × 2°). After bias removal, the statistically downscaled simulations based on the GFDL mini-ensemble mean indicate that the climate in the study area will experience significant changes with a large range of uncertainty according to the considered scenario and regional variations.

Regime Shifts in Future Shoreline Dynamics of Saudi Arabia

The Saudi Arabian tourism sector is growing, and its economy has flourished over the last decades. This has resulted in numerous coastal developments close to large economic centers, while many more are proposed or planned. The coastal developments have influenced the behavior of the shoreline in the past. Here we undertake a national assessment on the state of the coast of Saudi Arabia based on recent data sets on historic and future shoreline positions. While at national scale the shoreline is found to be stable over the last three decades, the Red Sea coast shows a regional-mean retreat rate while the Gulf coast shows a regional-mean prograding behavior. Detailed analysis of the temporal evolution of shoreline position at selected locations show that human interventions may have accelerated shoreline retreat along adjacent shorelines, some of which are Marine Protected Areas. Furthermore, reef-fronted coastal sections have a mean accretive shoreline change rate, while the open coast shows a mean retreat rate. Future shoreline projections under RCP 4.5 and RCP 8.5 show that large parts of the shoreline may experience an accelerated retreat or a change in its regime from either stable or sprograding to retreating. Under the high emission RCP 8.5 scenario, the length of coastline projected to retreat more than doubles along the Red Sea coast, and approximately triples along the Gulf coast in 2100. At national scale, the Saudi Arabian coastline is projected to experience regional-mean retreats of ~30 m and of ~130 m by 2050 and 2100 under both RCPs considered in this study. These results indicate that effective adaptation strategies will be required to protect areas of ecological and economic value, and that climate resilience should be a key consideration in planned or proposed coastal interventions.

Standing Crop Biomass and Carbon Content of Mangrove Avicennia marina (Forssk.) Vierh. along the Red Sea Coast of Saudi Arabia

A number of Avicennia marina mangrove forests exist along the 1134 km stretch of the Saudi Red Sea coast. Three areas, one in each of the north, centre, and south of the coast, were selected for this investigation into the relationship between total biomass (above-ground, AGB, and below-ground, BGB), and biomass carbon stocks of A. marina, along the nutrient availability (combined with a salinity gradient). To estimate the total biomass stock, this research employed equations formulated through a regression approach. Various population characteristics (tree crown diameter, height, and density) and measurements of carbon (C) in the trees were captured, and other measurements were gathered to represent the environmental properties: electrical conductivity (EC), total dissolved solids (TDS), and total phosphorus (TP) and total nitrogen (TN) levels. With this data from the 21 stands and 7 sites of A. marina covered by the three locations chosen along the coast, it was concluded that a discernible influence is exerted by the concentrations of TP and TN in the sea water and sediments over the population characteristics of this plant. The resulting estimates also demonstrated a steady increase in total biomass and total biomass carbon storage from the mangroves in the north toward the south, with values changing overall from 197.9 to 1188.2 Mg DM ha−1 and from 87.6 to 412.5 Mg C ha−1 respectively. This illustrates that the biomasses held by the southern mangroves are 6 times (total) and 4.7 times (total carbon storage) higher than those in the north.

Trauma and slavery, Gilo and the soft, subtle shackles of Lovedale

A recent study of sixty-four Oromo slave children from the Horn of Africa has provided valuable information of the children’s experiences from capture to the coast. In 1888 a British warship liberated a consignment of Oromo child slaves in the Red Sea and took them to Aden. A year later, a further group of liberated Oromo slave children joined them at a Free Church of Scotland mission at Sheikh Othman, just north of Aden. Two of the missionaries learnt Afaan Oromo (the children’s language), and, with the assistance of three fluent Afaan Oromo speakers, they conducted structured interviews with each child asking for details of their experiences of their first passage i.e. the journey from cradle to the Red Sea coast. When a number of the children died within a short space of time, the missionaries had to find another institution with a healthier climate to prevent further deaths. They decided to ship the Oromo children to the Lovedale Institution in the Eastern Cape, South Africa.