# Projected shifts in climatic suitability of olive (Olea europaea L.) in the Mediterranean

## TL;DR

This study predicts how climate change will shift suitable areas for olive cultivation in the Mediterranean, highlighting new opportunities and risks.

## Contribution

The study introduces a robust modeling framework with rigorous calibration and extrapolation diagnostics for predicting olive suitability under climate change.

## Key findings

- Minimum temperature of the coldest month is the main factor determining olive suitability.
- Future projections show a northward expansion of suitable areas, especially in France.
- Traditional olive regions face increasing climatic stress from heat and water scarcity.

## Abstract

Climate change is reconfiguring the spatial structure of agricultural landscapes worldwide. The Mediterranean Basin, a hotspot of change and the core region for olive cultivation, faces significant shifts in the distribution of this economically and culturally pivotal crop, with profound implications for landscape ecology, ecosystem services, and sustainability.

This study aims to assess current and future climatic suitability for olive cultivation (Olea europaea L.) across the Mediterranean Basin, identifying potential shifts in suitable areas under contrasting climate scenarios while explicitly accounting for model complexity, transferability, and extrapolation uncertainty.

We applied a species distribution modeling framework based on MaxEnt using 7,490 presence records and a set of bioclimatic predictors at 30 arc-second resolution. A baseline MaxEnt model was first developed to ensure comparability with previous basin-scale assessments. Model calibration and transferability were subsequently refined using the kuenm package, exploring multiple combinations of feature classes, regularization multipliers, and variable subsets. Future projections were generated under CMIP6 SSP1-2.6 and SSP5-8.5 scenarios for mid- and late-century periods. Extrapolation risk was evaluated using Mobility-Oriented Parity (MOP) analysis, while soil and aridity constraints were explored through post-hoc analyses.

Minimum temperature of the coldest month (Bio6) emerged as the dominant predictor of olive suitability. Model projections consistently indicate a northward expansion of climatically suitable areas, particularly in France, driven by the relaxation of winter temperature constraints. Traditional olive-growing regions in southern Europe and North Africa remain broadly suitable but exhibit increasing exposure to climatic stress related to heat, reduced chilling, and water scarcity. Post-hoc analyses suggest that soil type and aridity indices alone are insufficient to delineate suitability patterns at this spatial resolution.

Our results reveal a substantial reorganization of Mediterranean olive-growing landscapes under future climate change. While new opportunities may emerge in currently marginal regions, climatic suitability does not automatically translate into agronomic viability. Adaptation strategies in traditional areas and cautious planning in emerging regions will be essential. By integrating basin-scale modeling with rigorous calibration and extrapolation diagnostics, this study provides a robust and transparent framework to support adaptive planning and climate-resilient management of olive-based agroecosystems.