Climate Change Not Responsible for Fungal Disease Outbreak in Colombia's Coffee Crops

A new study reveals that climate change is not responsible for the recent outbreak of fungal disease damaging coffee crops across Colombia and neighboring countries.

The study, published in the journal Royal Society Philosophical Transactions B, found no evidence supporting the claim that climate change is increasing the probability of weather condition promoting the growth and spread of coffee leaf rust.

"The climate at the time was conducive to CLR but there had been earlier periods of similar conditions when there wasn't an outbreak," explained Dr Dan Bebber, lead author of the study, in a statement.

For the study, the researchers analyzed the weather conditions in the coffee-growing regions of Colombia from 1990 to 2015. The researchers found that the weather conditions from 2008 to 2011 were more conducive to coffee leaf rust outbreak. However, the researchers attribute the 40 percent decrease in Colombian coffee production not only to the weather conditions, but also to the financial crisis in 2008.

The researchers believe that the higher prices of fertilizers during the financial crisis have forced the farmers to treat coffee bushes less than they normally would. Furthermore, the researchers discovered that Colombian coffee yields are highly variable overtime due to varying weather, the effects of disease management and socio-economic factors.

Coffee leaf rust is an obligate parasitic fungus that thrives in areas with high moisture and moderate temperature, 21 to 25 degrees Celsius. In most cases, coffee leaf rust does not kill the coffee bushes. However, a coffee bush that is heavily infected with coffee leaf rust could dramatically decrease crop production.

With their findings, the researchers noted that more studies are needed to fully understand the underlying causes of the coffee leaf rust outbreak in Colombia. Thousands of people in the region have lost their jobs due to the outbreak. Additionally, future outbreaks of the fungal disease could endanger the livelihood of more than 120 million people across 70 countries.