More production in Africa, less olive oil in the Middle Eas due climate change
Climate warming will affect olive yield and fly infestation levels across the Mediterranean Basin, resulting in economic winners and losers at the local and regional scales
Inability to determine reliably the direction and magnitude of change in natural and agro-ecosystems due to climate change poses considerable challenge to their management. Olive is an ancient ubiquitous crop having considerable ecological and socioeconomic importance in the Mediterranean Basin. We assess the ecological and economic impact of projected 1.8 °C climate warming on olive and its obligate pest, the olive fly. This level of climate warming will have varying impact on olive yield and fly infestation levels across the Mediterranean Basin, and result in economic winners and losers. The analysis predicts areas of decreased profitability that will increase the risk of abandonment of small farms in marginal areas critical to soil and biodiversity conservation and to fire risk reduction.
The Mediterranean Basin is a climate and biodiversity hot spot, and climate change threatens agro-ecosystems such as olive, an ancient drought-tolerant crop of considerable ecological and socioeconomic importance. Climate change will impact the interactions of olive and the obligate olive fruit fly (Bactrocera oleae), and alter the economics of olive culture across the Basin. We estimate the effects of climate change on the dynamics and interaction of olive and the fly using physiologically based demographic models in a geographic information system context as driven by daily climate change scenario weather. A regional climate model that includes fine-scale representation of the effects of topography and the influence of the Mediterranean Sea on regional climate was used to scale the global climate data. The system model for olive/olive fly was used as the production function in our economic analysis, replacing the commonly used production-damage control function. Climate warming will affect olive yield and fly infestation levels across the Basin, resulting in economic winners and losers at the local and regional scales. At the local scale, profitability of small olive farms in many marginal areas of Europe and elsewhere in the Basin will decrease, leading to increased abandonment. These marginal farms are critical to conserving soil, maintaining biodiversity, and reducing fire risk in these areas. Our fine-scale bioeconomic approach provides a realistic prototype for assessing climate change impacts in other Mediterranean agro-ecosystems facing extant and new invasive pests.
The researchers’ study, published today in the Proceedings of the National Academy of Sciences, found that generally speaking, olive production in the region will probably grow—along with profits. Their model predicts that the region as a whole could see a 4.1 percent increase in crop yield and an 8 percent drop in olive fruit fly infestations, boosting profits by an average of 9.6 percent. Producers in North Africa will enjoy the biggest windfall, with a whopping 41 percent net increase in profits, according to the study.
In the Middle East, however, producers won’t be nearly as lucky. There, as warming temperatures stress olive trees and also allow the olive fruit fly to encroach into areas that were once too cold for them, net profits will likely drop 7.2 percent, on average.
“Climate warming will affect olive yield and fly infestation levels across the Basin, resulting in economic winners and losers at the local and regional scales,” the researchers wrote in the study.