Lebanon's Climate Is Becoming Less Conducive to Olive Growing

Scientists believe the loss of productivity and quality may occur in the Levant and the Mediterranean basin due to rising temperatures and less precipitation.

Rummana Camp near Dana village, Jordan
By Paolo DeAndreis
Feb. 15, 2023 15:41 UTC
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Rummana Camp near Dana village, Jordan

Olive grow­ers and oil pro­duc­ers across the Mediterranean basin have observed the chal­lenges caused by cli­mate change in the region.

New research now sug­gests that ris­ing sur­face tem­per­a­tures will sig­nif­i­cantly impact the region’s olive trees’ health and abil­ity to bear fruit.

We can see that tem­per­a­tures in those areas are going to exceed the thresh­old, and that might not be good news for the local olive tree pop­u­la­tion.- Rachid Cheddadi, researcher

A team of researchers focused on the cli­mate his­tory of Tyre, Lebanon, where olive trees have thrived for thou­sands of years.

They con­firmed that the cli­mate changes over time, slowly drift­ing away from ideal rain­fall and tem­per­a­ture con­di­tions for olive tree cul­ti­va­tion.

See Also:Ahead of a Bumper Harvest, Lebanese Producers Demonstrate Resilience

The research pub­lished in Nature Plants is based on ana­lyz­ing 5,400 years of pollen data from a 390-cen­time­ter sed­i­ment sam­ple col­lected in Tyre, 83 kilo­me­ters south of Beirut.

Once dated and treated, the pollen grains found in sed­i­ments offer deci­sive clues about tem­per­a­ture and other weather con­di­tions that accom­pa­nied the domes­ti­ca­tion of the olive tree in human set­tle­ments.

We used the pollen data, not only from olive trees but also sev­eral dif­fer­ent species, to recon­struct cli­mate data over time,” Rachid Cheddadi, co-author of the study and a bio­di­ver­sity researcher at the University of Montpellier in France, told Olive Oil Times.

By exam­in­ing the sam­ple layer by layer, researchers were able to mea­sure the dis­tri­b­u­tion and vol­ume of pollen through time and asso­ciate it with cor­re­spond­ing cli­mate con­di­tions.

To com­plete the pic­ture, the researchers used the cur­rent cli­mate data, ref­er­enc­ing 325 olive-grow­ing areas in the Mediterranean.

By asso­ci­at­ing the datasets and their find­ings, the researchers found that opti­mal grow­ing con­di­tions for olive groves include an annual aver­age tem­per­a­ture between 16.9 ºC and 18.3 ºC.

This thresh­old appears as the ideal con­di­tion for the opti­mal flow­er­ing and vital­ity of the olive tree, the best suit­able tem­per­a­ture for olive trees to grow,” Cheddadi said.

Further analy­sis of those data sug­gested that cur­rent and his­toric olive yields are impacted sim­i­larly by the same cli­matic and tem­per­a­ture con­di­tions.

The more the con­di­tions change, mov­ing away from that thresh­old, the more the species is impacted,” Cheddadi said.

By study­ing the past and cur­rent rain­fall pat­terns, the researchers spec­u­lated that the lower-than-ideal rain­fall lev­els in Tyre may have resulted in the local olive trees alter­ing the chem­istry of the dru­pes, chang­ing the fla­vor pro­file and nutri­tional con­tent of the olives.

This result is due to the chem­i­cal reac­tion of the trees to the lower amount of water, which can decrease the num­ber of fruit borne by the trees.

The researcher noted that if the olive tree under­goes freez­ing tem­per­a­tures for an extended period, its tis­sues might be dam­aged.

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In the same way, if the olive tree is sub­jected to high tem­per­a­tures, those might impact pho­to­syn­the­sis, with con­se­quences on the tree’s health and pro­duc­tive capac­i­ties,” Cheddadi said.

Climate change mod­els for Lebanon and the Levant show the dis­tinct pos­si­bil­ity that many his­toric olive-grow­ing regions may no longer be well-suited for the trees in the com­ing decades.

From those mod­els, we can see that tem­per­a­tures in those areas are going to exceed the thresh­old, and that might not be good news for the local olive tree pop­u­la­tion,” Cheddadi said.

The chal­lenges of cli­mate change 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 mit­i­gat­ing and adap­ta­tion strate­gies.

Climate events are becom­ing more fre­quent and vio­lent, as we have wit­nessed recently in Lebanon,” he said. During January, we wit­nessed tem­per­a­tures climb­ing as high as 25 ºC for about two weeks.”

At Solar, we adopt a bio­dy­namic approach to agri­cul­ture,” Arsanios added. We try to inter­vene as lit­tle as pos­si­ble, but given the cur­rent sit­u­a­tion and con­sid­er­ing pro­jec­tions for the next 10 years, we real­ize that we will be faced with more extreme weather events.”

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Solar Olives

The farm is study­ing ways to retain water more effi­ciently dur­ing the rainy sea­son. And we are eval­u­at­ing when an irri­ga­tion instal­la­tion would be appro­pri­ate,” Arsanios added. We are also try­ing to cre­ate an ecosys­tem that goes beyond sus­tain­abil­ity and becomes regen­er­a­tive.”

Predictions for how the cli­mate will change in the Levant are also pre­dicted to spread to the rest of the Mediterranean basin, which cli­ma­tol­o­gists con­sider a cli­mate change hotspot. The sur­face tem­per­a­tures of the whole region are ris­ing faster than in most other con­ti­nents and regions.

For Lebanon, this is the sce­nario, also because it is located on the south­ern edge of the range for many European trees, such as oaks and cedars,” Cheddadi said. This prob­lem that we face will first affect, of course, the coun­tries that are at lower lat­i­tudes.”

For local grow­ers, adapt­ing to new con­di­tions is a must. I can say that olive trees have been in this area for almost 7,000 years, and just like figs, they are men­tioned both in the Qu’ran and the Bible,” Arsanios said.

The olive tree played an impor­tant role in the econ­omy and civ­i­liza­tion over time,” he added. It was used for trad­ing olive wood with cedar wood, as fuel for lamps and to bake bread, and it was con­sid­ered a sym­bol of beauty, courage and fer­til­ity. In Arabic poetry and lit­er­a­ture, there are a lot of ref­er­ences to the olive tree.”

We can­not pre­dict the future,” Cheddadi added. So many dif­fer­ent areas and regions in the Mediterranean might have dif­fer­ent out­comes. On top of that, in many coun­tries, there are sci­en­tists who can han­dle the sit­u­a­tion and make pre­dic­tions. Policies and adap­ta­tion instru­ments might be stud­ied that can greatly help in address­ing the chang­ing cli­mate.”

At this stage, what we sci­en­tists are doing is to give a warn­ing that we must be care­ful and address the prob­lem,” he con­cluded.

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