In the scorching heat, Felipe Elvira inspects the branches of his olive trees, planted as far as the eye can see on a dusty hillside in southern Spain. "There are no olives on these. Everything is dry," the 68-year-old said.

He and his son operate a 100-hectare (250-acre) olive estate in the sun-drenched Andalusia province of Jaen, which produces the majority of the country's olive oil.

However, a severe drought affecting much of Spain this year threatens to reduce their yield. "We're used to a scarcity of water, but not to this extent," Elvira explained.

The region used to receive 800 liters (210 gallons) of rainfall per square meter but is expected to receive only half that amount this year, according to him. "Every year it's worse," Elvira observed.

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Spain is being harmed by global warming worse than most other European countries. Since May, the country has had three severe heatwaves, which have harmed crops already suffering from an exceptionally dry winter.

"Olive trees are very resistant to water scarcity," said Juan Carlos Hervas, an expert with the COAG farmers' union.

But when droughts become extreme, the trees "activate mechanisms to protect themselves. They don't die but no longer produce anything," he added.

'Absolutely dramatic' 

Hervas forecasts that the olive yield from unirrigated land will be less than 20% of the five-year norm.

He estimates that the harvest from irrigated land will be 50 to 60% of the average. However, water reserves are depleting.

The Guadalquivir river, which provides Andalusia with a large part of its water, is in "an absolutely dramatic situation" due to the lack of rain, said Rosario Jimenez, a hydrology professor at the University of Jaen.

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According to Spain's Ministry of Environmental Transition, reservoirs fed by the river are only 30% full.

"Some are even at 10 percent capacity -- that is practically dried up," said Jimenez. Farmers have also noticed changes in recent years.

"Not only does it rain less, but when it falls, it does so torrentially. The water flows without penetrating the earth," said Hervas.

Unless it accelerates energy transition steps and improves governance, #Europe will fail a major climate objective of cutting greenhouse gas emissions by more than 20 years.#ClimateEmergency #ClimateCrisis pic.twitter.com/aGGWEI4986

— Al Mayadeen English (@MayadeenEnglish) September 5, 2021

According to a study published this month in the journal Nature Geoscience, parts of Portugal and Spain are the driest they have been in a thousand years due to an atmospheric high-pressure system caused by climate change.

The issue is expected to worsen, threatening crops such as olives and grapes.

At stake is a key export: Spain supplies nearly half of the world's olive oil. Its exports of this "green gold" are worth some 3.6 billion euros ($3.7 billion) per year.