Weather conditions that reduce coffee yields have become more prevalent over the past four decades, and rising temperatures due to global warming are likely to lead to “continuing systemic shocks” in coffee production globally, a study suggests. new research.
The researchers analyzed the impacts of climatic factors such as temperature, rainfall, and humidity in the top 12 coffee-producing countries globally between 1980 and 2020.
The study, published in the journal PLOS Weather, found that the frequency of “weather hazards” (suboptimal growing conditions due to extremes such as high temperatures) had increased in all regions during that period. Five of the six most dangerous years occurred between 2010 and 2020.
Optimum growing temperatures for the two main coffee varieties, Arabica and Robusta, are 18-22°C and 22-28°C.
The researchers found that between 1980 and 2020, growing regions were more likely to experience too cold temperatures. “However, the current climate is characterized by excessively hot conditions in all regions,” they found, adding that “the vast majority of coffee-growing regions experience excessively cold temperatures during the growing season.”
The study’s lead author, Dr. Doug Richardson, who completed the research while at CSIRO, said the change from cool and wet to hot and dry conditions “we’re pretty sure is the result of climate change.”
The researchers wrote: “Given that climate change projections show a continued rise in temperatures in the tropics is likely, we suggest that coffee production can expect continued systemic shocks.”
“As with other crops, synchronized crop failures pose a systemic risk to the global coffee trade,” they added.
Previous research has shown that the amount of land suitable for growing coffee globally could be cut in half by 2050 due to climate change.
Richardson said: “If you have an impact on the supply of coffee in any given year, if there’s not enough coffee in storage from previous years, then you might expect the price to go up.”
The researchers also looked at the impacts of six different climate drivers on coffee production, including the El Niño-Southern Oscillation (Enso), the largest annual climate fluctuation on the planet.
“During El Niño events, we see a higher probability of conditions being too hot or too dry, and it’s more or less the opposite for La Niña,” Richardson said.
Although El Niño has global effects, it appears to have less of an impact in southern Brazil, the world’s largest producer of arabica beans. “It’s lucky that it’s less affected by Enso,” Richardson said. “What we hope is that during El Niño events, suppliers in southern Brazil can compensate for the reductions [in crop] elsewhere.”
The researchers found: “The major arabica regions in far southeastern Brazil and southwestern Ethiopia are among the regions least susceptible to climatic hazards.”
The top 12 coffee producers account for about 90% of world production. These include Brazil, Peru and Mexico in the Americas; Uganda and Ethiopia in Africa; and Vietnam and Indonesia in Southeast Asia.