By Peter Croce — February 28, 2025

 

Spain and Italy have a long history of olive cultivation, where generations of farmers have produced rich, distinctive olive oils thanks to special local climate conditions. In recent years, the two countries have been responsible for about half of global olive oil production, with Spain alone responsible for between about a third and nearly a half of global production in the last five years.¹

Yet, both regions have begun experiencing alarming crop failures. In Spain, a devastating prolonged drought in 2021 and 2022 slashed olive yields by 50% in the 2022/2023 harvest season compared Spain’s average production over the five years prior.² In Italy, 2018’s intense heat withered an estimated 50% of the olive crop, especially in regions like Puglia,³ and the 2024/2025 harvest is estimated to be down by about a third compared to the prior year.⁴
As climate conditions change, what can producers in Spain and Italy do to increase the resilience of their olive cultivation? To answer that question, let’s begin by developing literacy about the conditions that made these places ideal for quality olive oil production in the first place.

The Climate Conditions That Make Olive Oil

Olive trees, like all other plants, thrive in specific climate conditions. For centuries, the Mediterranean climate—characterized by mild, wet winters and warm, dry summers—has been ideal for olive cultivation. The wet winters provided enough water for olives to mature slowly throughout dry summers, and the moderate summer daytime warmth combined with cooler summer nights enabled olives to ripen gradually, which yielded olive oil with rich flavor profiles.⁵ The consistency of these conditions, year over year, was also essential: olives require two years of good conditions to go from an emerging bud to a mature fruit.⁶ This natural two-year cycle can be disrupted when hot and dry conditions distress the tree in either of the two years leading up to harvest.

Local climates and consistent rainfall patterns have historically ensured a bountiful harvest. But the situation is changing. As global temperatures rise, these once-predictable conditions are becoming less reliable.

The Risks of Increasing Heat

Warmer temperatures are now becoming more frequent and extending for longer periods of time in both Spain and Italy. Olive trees are experiencing greater heat stress, especially when the heat reaches extreme temperatures and lasts for days. Even in the cooler months, warmer winters are increasing the risk of pests and reducing “chill hours” that are crucial for tree fruits.

The increasing heat is not only threatening the health of trees but also altering the timing of olive harvests, affecting the quality and flavor of the oils. Olive fruit ripens faster in such conditions, which requires harvesting before the olives’ mature flavor profile has time to develop.⁷ With even warmer conditions expected across all seasons in the future, producers in Italy are facing a growing challenge unlike any in the history of olive oil production.

In the map below, we can see that in the past, different parts of Italy either never or rarely experienced days above 38°C (100°F), but many regions are expected to experience more of these very hot days if they experienced them rarely in the past, or to experience them for the first time.

On the left, the average number of days per year above 38°C (100°F) during the 1971 – 2000 period is shown, which was when the global average temperature was about 0.5°C warmer than the preindustrial global average. On the right, the same is shown for 2°C of warming, which is the climate expected around the 2040s. Click anywhere on the map to inspect the conditions there and drag the slider to compare the two scenarios. View the full global map on probablefutures.org.

The Risks of Drought

Both countries have already experienced periods of harmful drought. When conditions are too hot and dry, crop yields fall, and in more extreme conditions, trees die.

In southern Spain, the likelihood of drought lasting more than a year has increased from about 20% in most areas in the past to over 40% in most areas now that the global average temperature is close to 1.5°C of warming. Around the 2040s, or at about 2°C of global average warming, almost all of southern Spain is expected to experience more than 50% chance of drought. When the likelihood of drought is 50%, drought occurs once in every two years on average. When the likelihood is greater than 50%, an average year is more likely to experience drought than not.

Drought conditions stress olive trees, reduce water availability for irrigation, and disrupt the delicate balance necessary for high-quality oil production.

Here is a map showing how drought risk in southern Spain is changing due to climate change.

On the left, the likelihood of more than a year of drought during the 1971 – 2000 period is shown, which was when the global average temperature was about 0.5°C warmer than the preindustrial global average. On the right, the same is shown for 2°C of warming, which is the climate expected around the 2040s. Click anywhere on the map to inspect the conditions there and drag the slider to compare the two scenarios. View the full global map on probablefutures.org.

Adaption Increases the Resilience of Olive Oil Production

The weather conditions that allow for olive oil production in the Mediterranean are changing and will continue to change. Thankfully, there are reliable forecasts that can help cultivators develop the adaptation strategies that are essential to improve resilience and reduce crop failures in a changing world. Adaptation to these changing conditions may take many forms, from increasing water storage for irrigation to advanced pruning strategies.⁸ Other options may not even be imagined yet, but when they are, they are likely to be led by farmers and their wisdom developed over years of tending to olive groves.

Adaptation starts with climate literacy and domain expertise. Maps like those above depict future conditions but questions remain about what to do in the face of these changes. Olive cultivators are likely to be able to know the answer to those questions, with their deep experience in the art and science of olive cultivation. Informed about future conditions, experienced olive producers have the opportunity to interpret how future conditions will affect crops and identify interventions that are most likely to ensure bountiful olive harvests continue.

Conclusion

The rich history of olive cultivation in Spain and Italy dates back many thousands of years. During this climatically stable period, olive trees thrived and rich oils became an essential cultural and dietary touchstone in the Mediterranean region. As commerce globalized in the last century, olive oil became a staple for households around the world. Some of those households were home to climate scientists, and some of those climate scientists delivered us a gift: reliable information about the future.

Now, olive producers are faced with a remarkable opportunity to foresee and prepare for changing conditions. Their expertise with olive trees, combined with climate literacy and data, have the potential to preserve olive cultivation in Italy and Spain for future generations around the world to enjoy. For the love of the delicious oils we all enjoy thanks to them, let’s hope they do.

Further Reading

Probable Futures offers freely available climate literacy resources, maps, and data. We welcome you to read or listen to the climate handbook, learn more about how to measure climate change, gain deeper insights into issues like drought that affect global agriculture, or explore the maps.

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