| ABSTRACT | Mediterranean type-climate regions (MC) are characterized by a warm and dry summer season. Recent studies reveal that the observed temperature trends vary significantly between these regions, with the Mediterranean Basin warming faster than MC regions in the Americas, southern Africa and Australia. These differences in trends are attributed to various external or internal climate drivers. Nevertheless, the contribution of each driver is not well understood. We carried out two analyses in order to achieve a basic knowledge of surface temperature variability components related to anomalies of monthly temperature for the last four decades (1980 to 2020). First, a composite analysis using the ERA5 reanalysis dataset (2-m temperature and soil moisture), trying to identify the importance of land-atmosphere interactions. Second, a reconstruction of monthly anomalies based on the methodology by Lean and Rind (2008), which considers global Carbon Dioxide (CO2), Local Soil Moisture, Zonal Volcanic Aerosols, ENSO, and Global Total Solar Irradiance. We find that across the Mediterranean-type climate regions the local signal of temperature for the driest and wettest years varies. It is stronger in Mediterranean Basin, North America and southern Australia for dry and wet years (defined by the 10th and 90th percentiles respectively). Climate drivers play a fundamental role in surface temperature anomalies. For the northern hemisphere, the role of CO2 is more prominent (explains ~85% of temperature variability). Instead, in the southern hemisphere the relative importance of CO2 changes dramatically (below 50%), and other climate drivers, such as volcanic aerosols, explain most of the variability. Reference: Lean, J. L., & Rind, D. H. (2008). How natural and anthropogenic influences alter global and regional surface temperatures: 1889 to 2006. Geophysical Research Letters, 35(18), 1–6. https://doi.org/10.1029/2008GL034864 |