Climate Change Impacts Mediterranean Citrus

Turkey’s citrus industry has already experienced effects from climate change, Okan Ozkaya, professor at Cukurova University, reported in a recent World Citrus Organisation (WCO) presentation. His presentation was titled Impact of Climate Change in the Citrus Sector in Turkey and the Broader Eastern Mediterranean Area.

“Climate change has been a scenario for many years, but we started to see the effects and reality recently,” stated one of Ozkaya’s concluding slides. It added that “pest management, irrigation regimes and plant stresses started to be more severe.”

Ozkaya said climatic variables affecting fruit production include temperature, rainfall, light, wind, relative humidity, hail, and soil temperature and moisture. He said temperature rise due to climate change is predicted to lead to faster, shorter and earlier growing seasons as well as heat stress risk and increased evapotranspiration.

The past six citrus seasons in Turkey indicate that citrus plants are better equipped to deal with changing climate than other fruit crops because they flourish in the heat, Ozkaya reported. However, high temperature and high evaporation during flowering and fruit set result in low yield due to flower and fruit drop, he added. Additionally, fruit has poor color if temperature is high during fruit maturation, he reported.

Global mean temperatures have increased more than 0.74 degrees Celsius during the past 100 years and are expected to rise another 4 degrees Celsius by 2100, according to Ozkaya.

Another WCO speaker, Carlos Mesejo of Valencia Polytechnic University in Spain, addressed the potential impacts of climate change on citrus in the Western Mediterranean.

He said the problems associated with climate change include increase of temperature, extension of summer temperatures into fall, and an increase of extreme events including wind, heat and rain.

For instance, he stated that the potential impact of increased temperatures in the Western Mediterranean can be related to:

• Increased fruit drop
• Increased water demand
• Reduction of fruit size
• Changes in fruit acidity and sugars
• Physiological fruit disorders
• Modification of pest populations including mites and fruit flies