Climate change threat to coffee identified

Climate change threatens coffee production, researchers have found.
Date:29 April 2015

Climate change has been linked to declining coffee crops in the East African Highlands, according to research published in Agricultural and Forest Meteorology. Disastrous  yields have forced some farmers to quit – and there are warnings that it could get worse.

We needn’t think that this is a local phenomenon, either. The researchers also warn that attention should be drawn to the coffee regions of Brazil, Colombia, Costa Rica, Ethiopia and Kenya. There’s evidence that these areas have followed strikingly similar minimum temperature trends.

The team of scientists responsible for the study warns that, unless substantial climate change adaptation strategies are implemented, the average coffee production in Tanzania (where the study was conducted) will drop to around two-thirds of its current 225 kilograms per hectare by 2060. That could have massive implications for the world’s most valuable tropical export crop, which underpins an industry that supports an estimated 100 million people worldwide.

Using data from the northern Tanzanian highlands, the study verifies – for the first time – increasing night-time (minimum) temperature as the most significant climatic variable responsible for diminishing Coffea arabica coffee yields between 1961 and 2012. This is seen as proof that climate change is an ongoing reality.

“Coffee yields have declined to their lowest point in years, with many farmers in Tanzania giving up on coffee completely,” says lead author Alessandro Craparo, a PhD candidate from Wits University. “This is approximately a 35 % loss in yield for the farmer, which could mean a decrease of up to $28 million in export earnings for the country,” says Craparo.

Coffee is made from the roasted, ground seeds of the flowering plant coffea arabica – we know them as coffee beans. For sustainable growth, these plants need cool conditions like those found  like in the tropical highlands of East Africa, typically at 1 000 and 2 300 metres altitude.

According to the researchers, the hotter the nights get, the higher the danger for Arabica coffee production.  At night temperatures of 15°C and above, the plant’s metabolism starts to change, leading to lower yields and reduced quality, which will have a significant impact on the coffee industries and processors.

“This is the first study on coffee, globally, that provides essential time series evidence that climate change has already had a negative impact on Coffea arabica yields. Every 1° rise in minimum temperatures will result in annual yield losses of approximately 137 kilograms per hectare. For an average smallholder, production is currently around 225 kilograms per hectare,” Craparo explains.

In the face of this potential disaster, despite substantial government interest in the coffee sector, there is little matching involvement in analyses of coffee and climate change at regional or national levels.

 

Source: Wits University