The doom and gloom of climate change is well-documented: Rising sea levels; infectious diseases on the march; more frequent droughts. But a new study suggests that for olive oil production, climate change will be both a blessing and a curse. In the Mediterranean Basin, which produces 97 percent of the world's olive oil, average temperatures are expected to increase 2°C (3.6°F) between 2030 and 2060. Luigi Ponti, a researcher with the Italian National Agency for New Technologies, Energy and Sustainable Economic Development, wondered what that heat spike would mean for olive oil production. On one hand, olive trees are drought-tolerant, and people have made olive oil in the region since ancient times. On the other hand, no one knows how such rapid warming could affect production. To find out, he and his colleagues designed a model to predict how a 1.8°C increase in temperature would affect olive growth and yield in the region, and also how the olive fruit fly, the olive producer's nemesis, would fare. (Typically, these types of demographic models compare weather data with a species' geographic distribution to predict how climate change will affect it, but Ponti's team knew it was important to factor in the fly, since changes in its population can impact olive production.)
Olive Winners and Losers
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.
A model predicts which regions of the Mediterranean Basin may expect increased (yellow to red color range) or decreased (blue colors) profits (in euros per hectare) from olive crops after a 1.8°C increase in average temperatures. Image courtesy of Luigi Ponti. "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. It all depends on where olive groves will endure the most heat stress, and where olive fruit flies will thrive. Ponti's team has even more bad news for the areas where olive oil production is expected to wither: The disappearing groves could spur a cascade of economic and ecological consequences. As it becomes harder to make a living from growing olives, producers are likely to abandon their groves, potentially leaving the land more vulnerable to wildfires and soil degradation, which in turn could lead to a loss of biodiversity.
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