What Does the Land - Mediterranean Basin Climate Look Like at 2°C Warming?

The Coupled Model Intercomparison Project Phase six (CMIP6) models predict that, if global temperatures keep rising and reach 2 degrees Celsius (3.6 degrees Fahrenheit) above the baseline pre-industrial levels, people worldwide could face multiple impacts of climate change simultaneously, with serious consequences. The study of temperature changes is essential in order to determine and understand how different climate effects might combine. The objective of this master-thesis is to extrapolate the down-scaled climate projections (at 0.25° x 0.25°), provided by the NASA/NEX/GDDP data base on the Mediterranean basin, for the following five key climate variables: the mean near-surface air temperature (tas), precipitation (pr), near-surface relative humidity (hurs), surface downwelling radiation (shortwave: rsds, longwave: rlds). Four of the 35 available models participating to CMPI6, were used in this work to detect the crossing year in two different scenarios compared to the baseline temperature, namely: ACCESS-CM2, CESM2, GFDL-CM4 and EC-Earth3. The Shared Socio-economic Pathway (SSPs) scenarios considered in this study are SSP2-4.5 and SSP5-8.5. The first is an intermediate scenario, in which current climate change trends continue without substantial deviations, leading to a forcing pathway of 4.5 W m-2 by 2100 (Park, et al., 2023); the second scenario represents the upper boundary of the range of scenarios described in the 3 literature with an additional radiative forcing of 8.5 W m-2 by the year 2100. Also, the historical (1950-2014) background was used to easily determine the baseline temperature. This thesis, with the box analysis, will provide a time series of the 5 variables in seven selected locations in the Mediterranean Basin and it is going to highlight the urgent need for further studies focused on identifying the Mediterranean hotspots (Giorgi & Francisco, 2000). This may be helpful in suggesting region-specific actionable adaptation and mitigation plans. The baseline temperature over the seven locations was calculated, and it was 286.6750 Kelvin or 13.525 degrees Celsius. With the moving median method in MATLAB, we obtained 2026 as the crossing year for the SSP2-4.5 scenario, and 2025 for the SSP5-8.5 scenario. These results indicate that the Mediterranean region is critical climatic hotspot as a more complete study revealed the 2040 as the crossing year at global scale.