FEATURED SIGNS OF CLIMATE CHANGE AND THEIR IMPACTS ON AQUACULTURE IN THE SOUTHERN LEVANTINE BASIN

Climate change refers to significant and lasting changes in the Earth’s climate patterns over extended periods of at least 10 years, and preferred +30 years. These changes can be attributed to natural processes, such as volcanic eruptions and variations in solar radiation, or anthropogenic activities, such as burning fossil fuels and deforestation. Key aspects of change include global warming, extreme weather events, sea level rise (SLR), ocean acidification and ecosystem changes. These changes impact natural and human systems, affecting agriculture, water resources, meteorological parameters, health, biodiversity, fisheries and aquaculture.

The Levantine Sea is a prominent eastern Mediterranean sub-sea. It is surrounded to the north by the Cretan Archipelago and Asia Minor, to the east by the Middle East, and to the south by northern Africa. The Egyptian Mediterranean Coast borders the southern Levantine Basin, spanning from Rafah (east) to Sallum (west) along longitudes 24° to 35°E.

This talk highlights prominent signs of climate change along the southern border of the Levantine Basin. It summarises results from previous studies conducted in the area over different time spans and targeting various parameters.

Over 71 years (1948-2018), a consistent warming trend has been found for the analysed sea surface temperature (SST) data series, with a rate of 0.04°C per a, i.e., 0.4°C per decade. From 1975 to 1991, the mean annual SST was 17.1°C, and this increased to be 19.2°C over the period 2002–2018. Fluctuations in interannual SST and anomalies appear particularly in the southern Levantine SST from June to September.

The analysis of air temperature variations over one decade (2007-2016) revealed an overall positive trend for air temperature values in the Southern Levantine basin with a rate of increase of +0.56°C/decade. This value is in good agreement with the rates calculated for the Northern Hemisphere (+0.44°C/decade) and Europe (+0.50°C/decade) according to NOAA (2017). While the year 2010 had the highest mean annual air temperature at all of the recording stations, 2011 was the coldest year, with the lowest mean annual air temperature values.

The southern border of the Levantine Basin received a total amount of 8193.61 mm of rainfall over the period 2009-2020 (12 years), with a precipitation rate of 2.28 mm/rainy day. The indices of seasonal variations and precipitation concentration showed that rainfall variability along the southern border of the Levantine Basin is highly seasonal.

Over 46 years (1963-2008), the correlation between long-term variations in air temperature and hydrographic parameters (SST and sea surface salinity) and the total catch within the southern Levantine Basin (16 different species) revealed a special impact for the variation in the sea surface salinity on the catch (+0.51). The correlation factor between the total catch and the SST was 0.31, and with the air temperature was +0.29.