Summary 
The article discusses the threats facing olive cultivation due to climate change, including declining precipitation and solar activity, which challenges the long-term sustainability and productivity of olive farming in the Mediterranean. The study highlights the importance of adaptation strategies, such as genetic improvement and ecological practices, to mitigate the impact of climate change on olive production and maintain productivity in key growing regions.
As the Mediterranean climate becomes increasingly unpredictable, olive cultivation faces growing threats.
The severe impacts of climate change will become increasingly intertwined with decades of expected declining solar activity.
According to a recent study, such a scenario poses a challenge to the long-term sustainability, economic viability, and productivity of olive farming.
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The research, published in Communications Earth & Environment, examined 8,000 years of pollen records across the eastern Mediterranean.
These data provide a long-term perspective on how climatic variables, including precipitation and solar irradiance, have influenced olive yields over time.
A key contribution of the research lies in showing how changes in photosynthetic activity strongly modulate olive productivity.
While the physiological links between photosynthesis and factors such as light, rainfall, temperature, and carbon dioxide are well established, the new research reveals how long-term fluctuations in solar radiation and seasonal precipitation have historically influenced olive yields across the eastern Mediterranean.
“Today and in the coming decades, the primary drivers of water stress in Mediterranean olive-growing regions are declining precipitation and rising temperatures and evapotranspiration,” Nick Marriner, co-author of the study and director of research at the French National Center for Scientific Research (CNRS), told Olive Oil Times.
“Optimal yields occur within a narrow rainfall band of 330 to 370 millimeters. Beyond this window, fruit production drops sharply,” he added. “Compounding this, as rainfall decreases, evapotranspiration rates are expected to increase, placing additional pressure on already marginal growing areas.”
While this precipitation range provides a valuable benchmark, it does not apply uniformly across the Mediterranean.
“Although the indicator is based on historical and modern data, it is not necessarily universally applicable to all olive cultivars or regions,” Marriner said.
“In practice, the 330 to 370 millimeter range is a strong guideline, but regional variations in soil type, orchard management and cultivar characteristics may shift the optimal window slightly,” he added.
The study also highlights a lesser-known but emerging challenge: the approaching Grand Solar Minimum.
According to NASA, “during a grand minimum, solar magnetism diminishes, sunspots appear infrequently and less ultraviolet radiation reaches Earth.”
Such a phenomenon is expected to have only a slight impact on surface temperatures, which will continue to rise due to what 97 percent of climate scientists agree is human-caused global warming.
Still, during this period of reduced solar activity, the intensity of solar radiation reaching Earth will decline, which may potentially affect photosynthesis.
The researchers identified a 2,350-year cycle in olive pollen production that closely tracks solar activity, underscoring the role of radiation in shaping long-term yield trends.
“As global temperatures rise, higher evapotranspiration rates will further intensify water stress, especially in rainfed systems,” Marriner said. “Our study emphasizes that without irrigation, these conditions may exceed the adaptive limits of even drought-tolerant cultivars.”
“Olive trees could suffer irreversible photosynthetic damage,” he added.
This kind of damage has been observed in trees exposed to prolonged drought and heat stress. The permanent inability of the tree to convert sunlight into energy can occur.
In such conditions, recovery is commonly considered rare or even impossible.
To confront this multifaceted threat, adaptation will be essential. One promising avenue lies in genetic improvement.
“Cultivar selection and breeding are key tools in adapting to these stressors,” Marriner said. “Cultivars with early bearing capacity and tolerance to drought and low irradiance are already being developed, with new varieties like Askal, Barnea, Kadesh and Maalot.”
“In addition, pruning strategies that improve light penetration and canopy aeration can help optimize photosynthesis under reduced solar radiation,” he added.
The study estimates that the amount of precipitation required for efficient fruit development in most Mediterranean olive regions ranges from 290 to 410 millimeters during the phenological cycle, particularly from March to November.
When precipitation dips below this threshold, or when extreme weather shortens flowering and fruiting periods, both yield and oil quality suffer.
Adaptation strategies are already being tested across the region.
A 2024 study conducted in Spain evaluated 12 olive cultivars for drought tolerance under field conditions.
Researchers found that varieties such as Empeltre and Cornicabra showed greater physiological resilience under water stress, highlighting the potential for selecting cultivars better suited to future climate scenarios.
Other responses are ecological. In North Africa, for example, producers are increasingly adopting conservation practices such as mulching, utilizing organic soil amendments like biochar, and integrating cover crops to improve water retention and soil health.
These practices helped some growers maintain healthy orchards and achieve high-quality yields even in the record-dry 2023/24 crop year.
“A geographical shift is already underway and more may follow,” Marriner said. “Western Mediterranean [olive oil production] leaders like Spain and Italy have already seen yield declines.”
According to the scientist, the eastern Mediterranean is also facing sharp drops in output.
“If these trends continue, it is quite possible that we will see an expansion of olive production into more temperate zones, including northern Mediterranean or even Atlantic-facing regions,” Marriner said.
“In drought-affected regions, there will be increased reliance on irrigated plantations, although this raises sustainability concerns and other challenges,” he added.
In Lebanon, a traditionally rain-fed olive-growing country, studies have found that warming temperatures are shortening the growing season, potentially leading to increasingly erratic yields.
Those challenges are well known to local growers. Karim Arsanios, the owner of Solar Olives in northern Lebanon, told Olive Oil Times that his farm is continuously testing and adopting new mitigation and adaptation strategies.
“At Solar, we adopt a biodynamic approach to agriculture. We are trying to create an ecosystem that goes beyond sustainability and becomes regenerative,” Arsanios said.
According to the researchers, in the context of climate change, the balance that supported Mediterranean olive cultivation is increasingly fragile.
“Understanding the limits of olive tree adaptability is crucial. Our findings suggest that without proactive adaptation strategies, key olive-growing regions may struggle to maintain productivity,” the authors wrote in their study.
“Long-term sustainability will depend not only on biological and agronomic innovation, but also on recognizing and addressing the environmental thresholds shaping the viability of olive agriculture,” the researchers concluded.