The impact of the war in Ukraine on wheat production

Ahmad Al Bitar.  We cal­cu­lat­ed wheat crop yields using satel­lite data in two regions: Polta­va, an area far from the front; and Kher­son, which was invad­ed by the Russ­ian army. In 2022 (the year of Rus­si­a’s inva­sion of Ukraine), wheat yields in the Kher­son region fell by 20% com­pared to pre­vi­ous years: the amount of dry bio­mass (the amount of organ­ic mat­ter) decreased from 9.7 tons per hectare (t/ha) in 2020 and 2021 to 7.8 t/ha. In the Polta­va region, on the oth­er hand, yields remain sta­ble: this demon­strates the neg­a­tive impacts in areas invad­ed by the Russ­ian army. This affects the food secu­ri­ty of many coun­tries, since Ukraine was the world’s 5th largest wheat exporter in 2021. 

There are two dis­tinct ways in which it has had an effect. First­ly, access to plots of land is lim­it­ed due to the pres­ence of Russ­ian troops. This hin­ders agri­cul­tur­al prac­tices such as till­ing the soil, fer­til­is­ing and irri­ga­tion. The oth­er impact con­cerns human and mate­r­i­al resources. Farm­ers may fall vic­tim to the war or be recruit­ed to the front. And mate­r­i­al resources such as fer­tilis­ers or means of trans­port­ing wheat are affect­ed by the war. 

Our work does not allow us to dis­en­tan­gle the dif­fer­ent caus­es; fur­ther stud­ies com­bined with val­i­da­tion data will be nec­es­sary. Here we demon­strate that it is pos­si­ble to quan­ti­fy the impact of war with­in agri­cul­tur­al plots, at a res­o­lu­tion of 10 meters and over large areas. This work is car­ried out using satel­lite obser­va­tions and mod­el­ling, and there­fore with­out going into the field: this is unprecedented. 

Agri­cul­tur­al prac­tices homogenise crops to opti­mise yields. Here, on the con­trary, we observe het­ero­gene­ity of bio­mass with­in the plots. They look like plots left in their nat­ur­al state. We assume that the lack of agri­cul­tur­al prac­tices explains this drop in yield in the Kher­son region. 

We main­ly used data from Sentinel‑2, satel­lites launched as part of the Euro­pean Earth obser­va­tion and mon­i­tor­ing pro­gramme, Coper­ni­cus. These satel­lites car­ry opti­cal instru­ments, which pro­vide high-res­o­lu­tion images of the Earth in the vis­i­ble spec­trum (the equiv­a­lent of pho­tographs) and near-infrared. They make a com­plete cir­cum­nav­i­ga­tion of the plan­et every five days. 

One of the cru­cial fea­tures of the Coper­ni­cus pro­gramme is its com­mit­ment to the con­ti­nu­ity of long-term obser­va­tions. The oth­er cru­cial point is that the data is free of charge for sci­en­tists and pri­vate appli­ca­tions. This makes it pos­si­ble to cap­i­talise on the knowl­edge acquired in order to trans­fer these new method­olo­gies to oth­er regions of the world. 

It is of course very dif­fi­cult to car­ry out field stud­ies in war zones. Pre­vi­ous stud­ies have iden­ti­fied sig­nif­i­cant dis­rup­tions in the wheat dis­tri­b­u­tion chain, but it is dif­fi­cult to deter­mine the cause because mul­ti­ple fac­tors may be involved, such as the destruc­tion of trans­port infra­struc­ture, increased fer­tilis­er prices and pop­u­la­tion dis­place­ment. Our study makes it pos­si­ble to assess the direct impact of the Russ­ian inva­sion on crop growth. 

In gen­er­al, satel­lites are the tools of choice in dis­as­ter sit­u­a­tions. There is an inter­na­tion­al Char­ter on Space and Major Dis­as­ters that coor­di­nates the space response to dis­as­ters. Space agen­cies, gov­ern­ments and pri­vate com­pa­nies can mobilise their satel­lites to focus on the affect­ed areas and pro­vide data to emer­gency ser­vices and decision-makers. 

Two pre­lim­i­nary steps are nec­es­sary. The first con­sists of cor­rect­ing the satel­lite images for the effects of the atmos­phere and clouds using the MAJA tool from the French space agency CNES. The sec­ond step aims to iden­ti­fy the wheat plots. It is car­ried out by the com­pa­ny Kermap using arti­fi­cial intelligence. 

The Agri­Car­bon-EO pro­cess­ing chain is then applied. It inte­grates remote sens­ing data and agro­nom­ic mod­el­ling to pro­vide wheat pro­duc­tion maps with a res­o­lu­tion of 10 metres. Agri­Car­bon-EO is the result of ten years of research and devel­op­ment at CESBIO. All the tools were val­i­dat­ed in var­i­ous Euro­pean con­texts before being trans­ferred to Ukraine. 

Veroni­ka Anto­nenko. From the start of the study, we iden­ti­fied the impor­tance of ver­i­fy­ing the impact of the weath­er. By com­par­ing the weath­er in 2020, 2021 and 2022 with the cli­ma­tol­ogy of the last forty years, we found that the con­di­tions were with­in the norm in our two study areas. This allowed us to exclude the weath­er as an explana­to­ry fac­tor for this drop in yield. 

Interview by Anaïs Marechal