Report: Staple Crop Yields Will Drop as Global Population Grows

Climate change is affect­ing global farm­ing activ­i­ties, reduc­ing their cur­rent and future pro­duc­tion capac­ity.

While human pop­u­la­tion growth is pro­jected to con­tinue through 2050 and almost 50 per­cent more food will be needed, agri­cul­tural yields might drop or even col­lapse with harsh con­se­quences on all con­ti­nents.

This is the sce­nario emerg­ing from the lat­est Chatham House report, the data from which show that sta­ple crop pro­duc­tion may fall by 30 per­cent in the fol­low­ing decades, impact­ing food secu­rity for hun­dreds of mil­lion peo­ple and fuel­ing price increases for bil­lions.

The ​“Climate change risk assess­ment 2021” pre­sented to gov­ern­ments world­wide hints at the fact that with­out imme­di­ate action for sub­stan­tial green­house gas reduc­tion, the impacts on agri­cul­ture will be dev­as­tat­ing in a mat­ter of years.

“The chal­lenges come from mul­ti­ple sources and sce­nar­ios as whole regions of the world are expe­ri­enc­ing a cli­mate cri­sis that will ulti­mately hit bil­lions of peo­ple,” Daniel Quiggin, a senior research fel­low with the envi­ron­ment and soci­ety pro­gram at Chatham House, told Olive Oil Times.

“As an exam­ple, dur­ing the next decade, at least 400 mil­lion peo­ple will not be able to work out­side because of the too high tem­per­a­tures,” he added. ​“That will have a dra­matic impact on agri­cul­ture, and har­vest yields might be des­tined to fall also because of that.”

The report con­sid­ers the work­ing hours lost in 2019 and 2020 due to the Covid-19 pan­demic. It esti­mates that tem­per­a­ture increases led to the loss of at least 300 bil­lion work­ing hours in 2019 due to tem­per­a­ture increase, a 52-per­cent increase com­pared with data from 2000.

Devastating heat­waves, such as those expe­ri­enced in Australia or Siberia, are now between 10 and 600 times more likely due to the chang­ing cli­mate. At least 3.9 bil­lion peo­ple will be severely exposed to such heat­waves by 2040, result­ing in 10 mil­lion deaths each year from excess heat.

“No region will be spared,” wrote the report’s authors. ​“By 2040, major heat­waves will be expe­ri­enced each year by 50 per­cent or more of the pop­u­la­tions in West, Central, East and Southern Africa, the Middle East, South and Southeast Asia, as well as Central America and Brazil.”

“By 2050, more than 70 per­cent of peo­ple in every region will expe­ri­ence heat­waves each year,” the report added. ​“Urban areas will suf­fer the great­est chal­lenges of work­a­bil­ity and sur­viv­abil­ity.”

From an agri­cul­tural stand­point, per­sis­tent droughts con­tinue to threaten crop yields world­wide, includ­ing olives, wheat and cof­fee. Researchers believe that heat­waves and droughts have caused yield decreases of up to 50 per­cent in the worst years of the last decades.

While new tech­nolo­gies and research are help­ing many farm­ers bet­ter cope with the effects of the drought, experts believe that by 2040 at least 32 per­cent of global crop­land will be affected by severe drought with enor­mous con­se­quences on global food yields.

“Wheat and rice together make up 37 per­cent of global aver­age calorific intake,” the report said. ​“By 2050, more than 35 per­cent of the global crop­land used to grow both these crops will likely be exposed to dam­ag­ing hot spells each year, caus­ing reduc­tions to yields.”

The other aspect that increas­ingly will impact agri­cul­ture in many regions is the reduced grow­ing period for plants.

“Climate change will shorten the months dur­ing which the crops usu­ally pro­duce their yields, there­fore hit­ting the over­all pro­duc­tion capac­ity,” Quiggin said. ​“Adding to this, dur­ing the short­ened grow­ing peri­ods, the crops will also be more exposed to altered weather, so that the com­bi­na­tion of mul­ti­ple fac­tors might deter­mine a sub­stan­tial decrease of farm­ing capac­ity.”

Synchronous yield losses of 10 per­cent or more by the top four maize pro­duc­ing coun­tries, wrote the Chatham House experts, ​“would have dev­as­tat­ing impacts on avail­abil­ity and prices. Currently, there is a near-zero chance of this hap­pen­ing. However, over the decade of the 2040s, the risk of this increases to just under 50 per­cent.”

Current plans to coun­ter­act the impacts of cli­mate change are far from suf­fi­cient, warned the report’s authors.

If the so-called National Determined Contributions (NDCs) announced by many gov­ern­ments are enacted effec­tively, the report said there is a less than five per­cent chance of keep­ing tem­per­a­tures below 2 °C above pre-indus­trial lev­els. The pos­si­bil­ity of reach­ing the 1.5 °C tar­get set by the 2015 Paris Agreement is less than one per­cent.

“If pol­icy ambi­tion, low-car­bon tech­nol­ogy deploy­ment and invest­ment fol­low cur­rent trends, 2.7 °C of warm­ing by the end of the cen­tury is the cen­tral esti­mate, rel­a­tive to pre-indus­trial lev­els, but there is a 10 per­cent chance of warm­ing of 3.5 °C,” the report warned.

“These pro­jec­tions assume that coun­tries will meet their NDCs; if they fail to do so, the prob­a­bil­ity of extreme tem­per­a­ture increases is non-neg­li­gi­ble,” the report added. ​“A global tem­per­a­ture increase greater than 5 °C should not be ruled out.”

“Should NDCs stay as they are, many of the feared cli­mate change impacts will be locked in by 2040, so we actu­ally have between five and 10 years to sub­stan­tially cut the emis­sions,” Quiggin said. ​“Many of those impacts will go beyond what many coun­tries will be able to adapt to, so mit­i­ga­tion strate­gies are essen­tial.”

Mitigation includes plans for car­bon cap­ture, energy pro­duc­tion, defor­esta­tion, soil preser­va­tion and fos­sil fuel reduc­tion, wrote the Chatham House experts.

“The other front is adap­ta­tion strate­gies,” Quiggin said. ​“Even if we entirely decar­bonized the global econ­omy in the next 10 years, we would still have to adapt. That includes sus­tain­able farm­ing prac­tices, such as imple­ment­ing cor­rect crop rota­tion pat­terns and the diver­sity of crops thus avoid­ing mono­cul­ture which are less resilient.”

Adaptation will also mean upgrad­ing irri­ga­tion facil­i­ties in the drier areas.

“Still, many regions will be sub­jected to such an impact that their agri­cul­ture will not be able to adapt,” Quiggin said. ​“In those regions, many farm­ers and agri­cul­tural work­ers will have to find new jobs because farm­ing will not be able to offer the oppor­tu­ni­ties it tra­di­tion­ally had opened to them.”

The Chatham House report will be among the data sources dis­cussed dur­ing the upcom­ing inter­na­tional cli­mate sum­mit COP26 on October 31.

• Chatham House
• U.N. Food and Agriculture Organization