Mid-term impact of climate change on hazelnut yield

Abstract

The impacts of climate change on hazelnut production in Turkey—the world’s largest producer and exporter—may significantly affect the global hazelnut market depending on production and yield change. In this paper, based on gridded climate data with a 10-km horizontal resolution from regional climate model RegCM4.4 under the RCP8.5 business-as-usual scenario, multiple regression analysis was conducted to investigate yield change for the period of 2021–2050. We examined a total of 88 different locations and three phenological growth stages. We observed that hazelnut yield exhibits considerable variability depending on the phenological and sub-regional and the microclimate conditions in the humid-temperate Black Sea and the semi-humid Marmara regions. Until the middle of the century, we project that hazelnut yield will decrease up to 13% in approximately half of the current production areas. In addition, the fact that the majority of the decreases will be observed in the eastern Black Sea sub-region will cause hazelnut quality to be adversely affected. These findings are highly relevant in the context of regional development and trade in Turkey, and hazelnut processing and manufacturing sectors abroad.