Spatial variability of water-induced soil erosion under climate change and land use/cover dynamics: From assessing the past to foreseeing the future in the Mediterranean island of Crete

Climate change and land use/cover (LULC) changes are considered as main agents of soil erosion by water. Hence, evaluating both the past and future trends in rainfall and LULC patterns is crucial to seek their multi -temporal impacts on the erosion. In this line, the main objective of the present study was to assess the past and project the future variabilities of water-induced soil erosion under changes in rainfall and LULC patterns for the Mediterranean island of Crete (Greece). They were based on the estimation of soil loss rate by the GIS-based empirical model of RUSLE, and referred to three past periods (1991-2000, 2001-2010 and 2011-2020) and four periods of near and far future (2021-2030, 2031-2040, 2041-2050 and 2051-2100) under three different climate change scenarios (RCP2.6, RCP4.5 and RCP8.5). The relevant dynamics of R and C-factors incorporated in RUSLE were determined by using rainfall multi-historical observations and future simulations for the former, and LULC outputs derived from satellite images and CA-Markov model for the latter. The RUSLE outputs showed a gradual increase of mean soil loss during the past periods as a result of continuously increasing rainfall erosivity and bare land extent. However, the generally decreased levels projected for them in the future are expected to lead to a subsequent decrease of mean soil loss. In all cases, the mountainous parts of Crete and especially in the west were found to be more affected by erosion. Compared to the more recent past period of 2011-2020, the future period of 2041-2050 was projected to be the most notable in terms of potential risk, indicating the only scenario of increase (+0.4) in mean soil loss as well as the highest coverage (a total of 8 %) by areas of high and extreme loss. The RCP8.5 and RCP2.6 were projected to be the most negative climate change scenarios for the near (until 2040) and far (2040 onwards) future, respectively, presenting the smallest decreases (about-16 % and-5 %, respectively) in mean soil loss. The study's findings can offer knowledge indispensable for future sustainable policy-making and spatial planning.