Weakened Gulf Stream Will Have Major Impact on European Agriculture, Scientists Predict

Weakening ocean currents will likely increase incidences of extreme weather events, researchers warn, particularly in the Mediterranean Basin.

Sep. 2, 2021
By Paolo DeAndreis

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The engine” behind the sta­bil­ity of the con­di­tions that have helped Mediterranean farm­ers grow their crops for cen­turies is under­go­ing a major change.

Spain and Italy are among the first places to expe­ri­ence a new and unpre­dictable cli­mate phe­nom­e­non that is rapidly extend­ing across the Mediterranean basin.

What is hap­pen­ing is con­nected to the ongo­ing weak­en­ing of the pow­er­ful ocean cur­rents in the Atlantic, which bring huge amounts of warm water from south­ern and mid­dle lat­i­tudes to the European coast.

It is weak­en­ing. It is almost gone, and this causes the two masses, cool and warm, to clash over south­ern Europe with the con­se­quent extreme weather events we are more and more often wit­ness­ing.- Gianmaria Sannino, oceanog­ra­pher, ENEA

According to new research, the effects of the weak­en­ing Atlantic Meridional Overturning Circulation (AMOC) on the world’s cli­mate are huge and will impact at least three con­ti­nents.

The study authored by the German cli­ma­tol­o­gist Niklas Boers and pub­lished in Nature warns that the AMOC is reach­ing a crit­i­cal tran­si­tion, a tip­ping point beyond which even stronger cli­mate effects are to be expected.

See Also:Researchers Work to Identify Olive Varieties Best Adapted to Higher Temperatures

Looking at the evi­dence of the AMOC weak­en­ing is rel­e­vant because it tells us that we face a dif­fer­ence which is shrink­ing between tem­per­a­tures among waters in the trop­i­cal areas and those in the north­ern polar region,” Gianmaria Sannino, an oceanog­ra­pher and direc­tor of the cli­mate mod­el­ing and impact lab­o­ra­tory at the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), told Olive Oil Times.

AMOC is dri­ven by tem­per­a­ture. The cold north­ern region of the ocean attracts the warmer waters, cre­at­ing a stream that has played a piv­otal role in reg­u­lat­ing Earth’s cli­mate for mil­len­nia.

It is the engine of cli­mate on Earth since oceans are the most rel­e­vant cli­mate reg­u­la­tor,” Sannino said. Ninety-three per­cent of the heat pro­duced by global warm­ing is found in the oceans.”

While changes in the atmos­phere often come abruptly and impact pop­u­la­tions and crops, and are eas­ily vis­i­ble, those in the oceans are harder to see, build up slowly and bring huge con­se­quences to the whole sys­tem for much longer peri­ods of time,” he added.

The new study con­firmed the find­ings of sev­eral pre­vi­ous ones regard­ing how major changes in the AMOC could bring about a more rapid rise in sea lev­els on the east coast of the United States, per­sis­tent droughts in West Africa and sub­stan­tial cool­ing of north­ern Europe.


While many other effects are to be expected, the first region to feel the change will be the Mediterranean basin.

What cli­ma­tol­o­gists have dis­cov­ered is that south­ern Europe is a very spe­cific cli­matic hotspot, where cli­mate change effects are espe­cially evi­dent and hap­pen before than else­where,” Sannino said.

The basin and its agri­cul­ture have long enjoyed the mod­er­at­ing pres­ence of the Mediterranean Sea.

Rome has the same lat­i­tude as Boston, but the cli­mate is sharply dif­fer­ent because Rome is in the mid­dle of a very big lake,” Sannino said. This dif­fer­ence will be lost because of all the energy we released in the atmos­phere and in the oceans since the pre-indus­trial era.”

Regional cli­mate data, which informed the United Nations’ Intergovernmental Panel on Climate Change (IPCC) report, show that the Azores High, a high-pres­sure weather sys­tem that influ­ences the cli­mate of Europe and North Africa, is almost gone as a result of the weak­en­ing AMOC.

During sum­mer, the Azores High keeps the cooler north­ern air masses sep­a­rate from the hot African cir­cu­la­tion, cre­at­ing mod­er­ately warm sea­sons that favor agri­cul­ture and farm­ing.

It is weak­en­ing. It is almost gone, and this causes the two masses, cool and warm, to clash over south­ern Europe with the con­se­quent extreme weather events we are more and more often wit­ness­ing,” Sannino said.

If noth­ing will be done to reduce global emis­sions and cur­tail the effects of cli­mate change, cli­ma­tol­o­gists expect tem­per­a­tures in the Mediterranean basin to rise up to 5 ºC by the end of the cen­tury, well above the expected global pro­jec­tions.

Spain and Italy, the world’s two largest olive oil pro­duc­ers, are at the fore­front of this change. Droughts and deser­ti­fi­ca­tion already threaten their agri­cul­tural sec­tors and are expected to become even worse.



The heat­waves we had this sum­mer are just the begin­ning,” Sannino said. If we cur­rently con­sider these heat­waves abnor­mal since they hap­pen every few years, by the end of the cen­tury we will have heat­waves that will not last a few days, but for sev­eral weeks. They will be hot­ter and will occur in a sum­mer that will have an early begin­ning and a late end­ing.”

Longer, hot­ter and drier sum­mers will have a pro­found impact on olive grow­ing. Already, hot­ter and drier springs in Andalusia, the world’s largest olive oil-pro­duc­ing region by a large mar­gin, are lead­ing to ear­lier flow­er­ing in olive trees and increased dam­age from heat stress events.

Additionally, a 2020 study con­ducted by researchers in Israel demon­strated that higher-than-usual tem­per­a­tures affected olive fruit growth and weight, oil accu­mu­la­tion in the fruit and its chem­i­cal com­po­si­tion.

A sep­a­rate study in Andalusia showed that hot­ter and drier con­di­tions in the south­ern Spanish region could sub­stan­tially decrease the abil­ity of seven endemic vari­eties, includ­ing the prodi­gious Picual, to grow nat­u­rally there.

Francesco Muschitiello, a geo­g­ra­pher spe­cial­iz­ing in pale­o­cli­ma­tol­ogy at the University of Cambridge, told Business Insider that a shut­down of the AMOC is the eas­i­est, most effi­cient way to dis­rupt the cli­mate sys­tem.”

Ninety-five per­cent of the time, when we talk about rapid cli­mate change, it’s asso­ci­ated with AMOC,” he added.

According to Boers, as quoted by Business Insider, it typ­i­cally took a few hun­dred to a few thou­sand years for the AMOC to go back to the strong mode.”

If the AMOC were to col­lapse to the weak mode at some point in the future, it would indeed be very hard to bring it back to the strong mode,” he added.

Climatic con­di­tions will keep chang­ing over the next decades and that will require farm­ers to adopt new efforts in order to guar­an­tee their yields and income.

Precision and tech­no­log­i­cal agri­cul­ture means increas­ingly will be needed,” Sannino said. We will have to focus on the sus­tain­able man­age­ment of the water resources, irri­ga­tion and so on.”

More than any other sec­tor, agri­cul­ture is affected by cli­mate change and at the same time, it is one of the most rel­e­vant con­trib­u­tors to the causes of the change itself,” he added. The world needs a smarter and more sus­tain­able agri­cul­ture to face a weather becom­ing more unpre­dictable.”


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