Do regional marine climate matter in crop production? Assessing the effect of sea surface temperature on cereal yield in European Union countries in the Baltic and Mediterranean sea regions

In this study, we investigated how marine climate variability, particularly sea surface temperature influences cereal yield in selected European Union countries from 2000 to 2023. Using panel data from seven coastal and four inland countries, we analysed the effects of sea surface temperature on surface air temperature, precipitation, and relative humidity, and their subsequent impact on cereal yield, while controlling for harvested areas. Pooled, first-difference, and two-way fixed effects models revealed that sea surface temperature significantly increases surface air temperature and precipitation while reducing relative humidity, with relative humidity showing a nonlinear relationship with yield. A Difference-in-Differences model approach centred on the 2015–2016 El Niño event confirmed a significant post-treatment yield decline in coastal countries, reinforcing sea surface temperature’s indirect but important role in shaping crop productivity. These findings imply that the European Union agricultural and climate adaptation policies should explicitly integrate marine climate indicators, in particular, sea surface temperature anomalies into regional risk assessment and resilience planning, especially for coastal farming systems.