Climate change threatens olive oil production in the Levant

Abstract

The olive tree (Olea europaea L.) is one of the best-adapted species to Mediterranean-type climate 1-8 . Nonetheless, the Mediterranean Basin is deemed to be a climate change "hotspot" by the IPCC 9,10 because future model projections suggest considerable warming and drying 11,12 . Within this context, new environmental challenges will arise in the coming decades, which will both weaken and threaten olive-growing areas, leading to a loss of productivity and changes in fruit and oil quality [13][14][15] . Olive growing, a core of the Mediterranean economy, might soon be under stress. To probe the link between climate and olive trees, we here report 5400 years of olive-tree dynamics from the ancient city of

A history of olive and grape cultivation in Southwest Asia using charcoal and seed remains

“…From Fig 11 it is visible that few sites with olive are found below 250 mm (reconstructed) annual rainfall. While that is the conventional dryland cultivation border, it is generally known that olive does not thrive and produce many fruits below 400 mm of rainfall [ 24 ]. Fig 12 depicts the sites below 400 mm (reconstructed) rainfall.…”

“…Both lows during these times suggest a possible aridity impact on olive and grape cultivation. The typical dependance of olive cultivation on rainfall, and its extension somewhat away from its natural distribution especially between 4000 and 2000 BC ( Fig 14 ), makes it prone to increased aridity which would particularly decrease in yield [ 24 ]. Since grapes are sensitive to drought stress [ 72 ], water scarcity may have affected grape production as well, despite certain precautionary measures, such as irrigation in the generally more arid regions.…”

“…Grape vines can be damaged by temperatures around -15 and -20 °C [ 54 ], while olive is not able to survive below -12°C and severe frost damage occurs already at -7°C [ 79 ]. Kaniewski et al [ 24 ] have shown that the optimal mean annual temperature for olive is 16,8°C and that temperature changes have affected olive growth and yields in the Tyre region of the Levant through time.…”

“…Such instances of social unrest are thought to relate to climate change [23] which has been argued to have caused an overall system collapse at that time [22]. While some palynological studies have investigated the impact of climate change on fruit tree cultivation for specific regions and periods of Southwest Asia [24][25][26][27], no supra-regional investigations have been undertaken exploring the role of former rainfall and temperature in decisions related to investments in olive and grape cultivation and the possible consequences of climate change on crop yields and the nourishment of the population.…”

Cold stress resilience of Iranian olive genetic resources: evidence from autochthonous genotypes diversity

“…The Middle East region and Iran are also affected by this problem. Spells of extreme heat and cold out of the usual season are among the consequences of climate change ( Kaniewski et al., 2023 ). On the other hand, adaptation enables plants to overcome changes in the environment that can be used as a criterion for selecting plant materials that display high adaptability to new environmental settings ( Kawecki and Ebert, 2004 ; Gibson et al., 2016 ).…”