Chocolate faces more climate shocks as study highlights risk of extreme rainfall

The road to chocolate starts with these beans, and they face many threats including too much rain during the wet season, says a new study. (Francis Kokoroko/Reuters)Social SharingAs stores around the country trot out hyper-bright boxes of bite-sized chocolate for Halloween, a new peer-reviewed study says there's an underappreciated threat that cocoa production faces. 

"People have tended to focus on heat and drought as the main climate risks, and those do matter," said Anna Lea Albright, who led this research as an environmental fellow at Harvard University.

"But what we found is that the strongest weather risk to cocoa is actually heavy rainfall." 

Cocoa prices have shot up in recent years and consumers have felt it. Today, a tonne of cocoa hovers around $6,000 US, from a relatively long period of trading around $2,000 to $3,000 US per tonne since 2014. In 2024, the price shot up to over $12,000 US. That was triggered by multiple factors including heavy flooding in West Africa, where more than two million farmers help make it the world's biggest cocoa-growing region.

Boo! Chocolate prices are haunting Halloween shoppers

Leslie Agyare, founder of Three Mountains Cocoa, which works with thousands of farmers in a mountainous region of Ghana, says the rainfall has been a real challenge this year. 

"Just imagine, you manage your whole crop, then it's raining so much and you can't harvest because the rains are just too much," Agyare told CBC News from London, England.

But even as climate change, driven by humanity's burning of fossil fuels, is expected to make extreme rainfall events worse, the authors say there are ways to mitigate the impact on this crop that billions of people enjoy. 

The study, published in the Proceedings of the National Academy of Sciences, focused on Ghana, the world's second largest producer of cocoa. Using newly available district-level data on production, the authors compared that to rainfall and temperature data. 

"When we did that pairing, extreme rainfall during flowering stood out as limiting yields, much more so than temperature during those months," Albright told CBC News from Paris. While cocoa trees need this moisture during the wet season, too much of it can damage the sensitive flowers and young pods. 

The tiny flowers that grow on cocoa trees are very sensitive and heavy rains can damage them. (Ricardo Moraes/Reuters)Wet conditions, Albright says, can also lead to more fungal infections — such as black pod disease — that are spread by splashing rain. The connection between extreme rain and lower yields was also found when the team looked at other cocoa-producing countries, Ecuador and Indonesia. 

The research also found a clear climate signal, as warmer air holds more moisture. 

"In the satellite record, in rain gauges, we see [evidence] over the past few decades that the heaviest rain events during the wet season are indeed becoming more intense," Albright said.

It's worth noting that in West Africa, El Niño typically reduces the risk of extreme rain but raises the chance of drought, which the region is expecting. 

"Now there is a dry period — when they need the rain, there is no rain," Agyare said. 

The typical challenge for cocoa farmers is a lack of rain, leading to dried-out pods like this. (Issouf Sonogo/AFP/Getty Images)Losing ground  While underappreciated, extreme rainfall's impact on crops isn't a new danger. The study also points out non-climactic risks like aging trees and illegal gold mining, which the UN Food and Agriculture Organization says is part of multiple threats to cocoa production.

Still, Sophia Carodenuto, environmental governance expert and associate professor at the University of Victoria, appreciates the study's findings, but says the key question remains about what farmers can do about it. 

"You cannot stop rain, especially extreme rainfall," Carodenuto said, acknowledging the authors hinted at potential interventions involving fungicide and better drainage to mitigate spread of fungal diseases.

For Agyare, the solution requires serious infrastructure investment. 

"For some areas that we work with, once it rains, the farmers are trapped in that area," he said. "These are kids that can't go to school. These are families that are stuck." 

Many farmers also don't have reservoirs to save some of that rainwater for later use. But a major issue, Agyare says, is a system that puts too much work on the farmer. 

Two cocoa farmers spread cocoa beans during the sun-drying process in Asikasu, a village in Ghana, in December 2020. (Cristina Aldehuela/AFP/Getty Images)"In Ghana, they have two issues. The farmers farm, then they do all the post-harvest themselves," he said, suggesting that splitting the post-harvest duties with other labourers would allow farmers to focus on growing only.

This would allow for collection and processing to be done in a centralized area, avoiding the losses that come from farmers drying their beans on the land and losing them during torrential rains. 

These climate shocks, experts say, are making the job of cocoa farming unattractive in West Africa, and a lot harder. 

"I think smallholder farmers are going to be a thing of the past," Agyare said, adding that children don't want to get into what their parents are doing and prefer to find opportunities in the cities. 

Carodenuto questions whether adapting to the changing climate will eventually be too much, forcing people out of the job. That will add to the price volatility, which won't just edge out farmers, but push chocolate producers to ditch cocoa in chocolate altogether.

"It's been [a] completely crazy spike in price that I think was a major instigator for a lot of the innovation around cocoa-free chocolate," she told CBC News from Graz, Austria, adding that alternative chocolate is being promoted as less vulnerable, with a more resilient supply chain. 

Earlier this year, the world's largest food company, Nestlé, entered the space, partnering with a German cocoa-free chocolate startup. That company makes ChoViva, an alternative that uses sunflower seeds, which Carodenuto says is attractive in terms of supply chain control because it's grown in Europe.

Hardened chocolate before the packaging stage. (Valentine Chapuis/AFP/Getty Images)Even a significant rise in price, she says, won't result in a better future for the people who grow and harvest cocoa. 

"Chocolate, especially the type of chocolate that you give out for trick-or-treating at Halloween, it's been so historically underpriced," Carodenuto said. 

"And who's been footing that bill? It has been smallholder farmers in West Africa." 

Anand Ram is a reporter and producer with CBC's science and climate unit. He's worked as a reporter covering technology, business and the environment and as a producer with The National.