Mapped: 16 times extreme weather drove higher food prices since 2022 – Carbon Brief

UK potatoes, South Korean cabbage and west African cocoa are just some of the foods that became markedly more expensive after extreme weather events in recent years, according to new research. 

The study, published in Environmental Research Letters, analyses 16 examples of food price rises across the world that followed periods of extreme heat, drought or rainfall over 2022-24. 

A “striking” example, according to the lead author, is the wide-ranging price impact following a 2024 heatwave in Asia, which saw cost increases from onions in India to rice in Japan. 

Soaring food prices have been a major concern for consumers around the world since around 2021, with prices rising due to extreme weather fuelled by climate change, higher production costs and Russia’s invasion of Ukraine – among other factors. 

The new findings act as a “stark reminder” of the “significant pressure” climate change is already having on crops, a researcher not involved in the study says. 

Effects of weather extremes 

Extreme weather has both immediate and long-lasting impacts on food production. It can destroy growing crops, impact yields and even weaken food supply chains. 

One impact frequently tied to climate change is the rising cost of food. The price of everything from olive oil to eggs, and from chocolate to rice has fluctuated in many parts of the world in recent years. 

The new study analyses 16 examples of increased food prices after a period of extreme weather over 2022-24. The researchers then assess how unusual the extreme heat, drought and rainfall events were compared to historical climate data.

These case studies are outlined in the map below. The shading indicates the percentage by which each weather extreme exceeded past climate data from that time period. 

Many events, indicated by the darkest shading, “were so extreme as to completely exceed all historical precedent prior to 2020”, the study says. 

The analysis is based on temperature data from Copernicus ERA5 spanning 1940-2024 and the Standardized Precipitation Evapotranspiration Index spanning 1901-2023, along with reporting from a range of news outlets and food price data from governments and industry groups. 

(ERA5 is a reanalysis dataset that combines climate observations with model simulations.)

Dr Maximilian Kotz, a postdoctoral fellow at the Barcelona Supercomputing Center and the lead author of the new study, explains that some of the examples involve multiple types of extreme weather, such as intense heat and drought. But the researchers chose the extreme which occurred closest to the price rise for “simplicity of communication” on the map. 

The research team selected “prominent” case studies, Kotz tells Carbon Brief, where the “effects are so obvious…that you don’t need a substantial, quantitative statistical analysis to see them. The people on the ground can see that this is what’s happening.” 

The 2024 heatwave in Asia was a particularly “striking” example, he says, adding: 

“What’s so interesting there is how widespread that exceptional heat was and also how ubiquitous these effects [on food prices] essentially were towards the end of last summer. 

“India, China, South Korea, Japan, Vietnam – all of these countries that all experienced really exceptional heat…and all of them had documentation of these kinds of effects, to some extent.” 

The study authors note that while the 2023-24 El Niño “likely played a role in amplifying a number of these extremes”, the increased intensity and frequency of the events is “in line with the expected and observed effects of climate change”. 

(Other researchers have carried out rapid attribution analyses to assess the role of climate change in a number of the events included in the study, such as UK winter rainfall in 2023, Pakistan floods in 2022 and Ethiopian drought in 2022.) 

In the UK, food price inflation is still rising as retailers partly blamed “hot weather hitting harvest yields”, the Guardian reported. 

Cabbage, olive oil and rice 

Government statistics indicate that extreme heat across east Asia in 2024 contributed to the cost of cabbage in South Korea rising 70% and rice in Japan increasing 48% from September 2023 to September 2024, the study says. The same heat also contributed to a 30% rise in the cost of vegetables in China between June and August 2024. 

China, South Korea and Japan were among the many countries to experience their hottest year on record in 2024. 

In the US, the researchers find that an “unprecedented” drought in California and Arizona across 2022 contributed to an 80% increase in vegetable prices between November 2021 and November 2022. 

Droughts in southern Europe in 2022-23 drove a 50% price increase in olive oil across the EU from January 2023 to January 2024. Spain is the world’s largest producer of olive oil, followed by Italy – both of which were badly affected by the drought. 

Cocoa was another commodity whose price has soared globally in the past couple of years. This was due to a number of factors, the study says, including extreme weather in Ghana and the Ivory Coast where more than 60% of the world’s cocoa is grown. 

Many parts of the two west African countries experienced “unprecedented” temperatures of up to 50C in February 2024, following a “prolonged drought” in 2023. 

The “dangerous”, humid February heat was made about 4C hotter due to climate change, according to analysis from the World Weather Attribution group. 

The new study also looks at coffee price increases after extreme heat in Vietnam in 2024 and a 2023 drought in Brazil. 

Kotz said the most notable examples of price rises were with commodities such as cocoa and coffee, which are available globally, but produced in concentrated areas – opening up the “possibility for greater volatility” in the event of weather extremes. 

‘Knock-on’ effects

A 2024 study by Kotz and researchers at the European Central Bank found that high temperatures increased food inflation “persistently” for 12 months after the extremes in both high- and low-income countries. 

Kotz says the new study is a “follow up” to this research. It discusses some of the other factors impacting the food prices in the study, such as high transport costs contributing to rising food prices in Ethiopia, as well as rising production costs and high tourist demand contributing to soaring rice prices in Japan. 

The findings are a “stark reminder that climate change is already putting significant pressure on crop production globally”, says Dr Jasper Verschuur, an assistant professor of engineering and climate security at Delft University of Technology in the Netherlands. 

Verschuur, who was not involved in the research, tells Carbon Brief: 

“This study also stresses that the impacts of shocks to the agricultural sector can have cross-sectoral impacts – for instance, to health, political stability and monetary policy – which are rarely ever captured in modelling studies.” 

He notes that while understanding of local impacts of extreme weather on crop yields and price has “improved”, the wider impacts and dual effects of climate and non-climate “shocks” are still less well-understood. 

The researchers discuss some of the “knock-on societal risks” from rising food prices in the study, such as increasing economic inequality, malnutrition and an overall increase in inflation. 

In a statement about the new research, Shona Goudie, the policy and advocacy manager at the Food Foundation, a UK charity whose executive director was involved in the study, says:

“Increasingly frequent price shocks due to climate change could see food insecurity and health inequalities deteriorate even further.”