DAR ES SALAAM, April 27 (Thomson Reuters Foundation) - Warmer weather means that Tanzania is producing less coffee as higher temperatures affect yields, hurting both the nation's producers and coffee drinkers who may pay more per cup, a South African university has found.
According to a study conducted by the University of Witwatersrand, researchers have established that higher night-time temperatures are the main factor behind a significant decline in Tanzania's Arabica coffee yields.
Coffee is Tanzania's largest export crop; on average the country produces around 50,000 metric tons each year of which approximately 70 percent is Arabica. Sales generate over $100 million per year, according to data from Tanzania's Coffee Board.
The East African nation produces less than 1 percent of the world's Arabica coffee, but the industry employs about 2.4 million people in Tanzania and several millions in neighboring countries.
Since 1966, however, coffee production has dropped by 46 percent in Tanzania - a trend research predicts is likely to continue. Over that period, Tanzania's night-time average temperature has risen by 1.4 degrees Celsius.
1 DEGREE RISE, HALF THE COFFEE
According to the study, published in the journal Agricultural and Forests Meteorology, for each 1-degree Celsius rise in mean minimum (night-time) temperature, farmers in Tanzania are likely to see a loss of approximately 137 kilograms of coffee per hectare. That is almost half the average small producer's production, which is currently 225 kilograms per hectare.
Negotiators at U.N. climate talks are working toward a global agreement to limit global warming to 2 degrees Celsius - but the world is currently on a path toward at least 4 degrees Celsius of warming by the turn of the century, scientists say.
"Our forecast indicates that if the trend continues as has been observed during recent decades, then Arabica coffee production in Tanzania will drop to 145 kg per hectare by the year 2060," the University of Witwatersrand study said.
Researchers say the threat to Tanzania's coffee production should spur the country's authorities to design climate-smart practices that might help cushion farmers from worsening losses.
The study, which looked at the impact of climate change on Tanzania's Arabica coffee production over the past five decades, warned that dwindling coffee yields will affect incomes and jobs not only in Tanzania but in other coffee producing countries such as Kenya, Ethiopia, Brazil, Colombia and Costa Rica, which could also see temperature rises.
In Tanzania, Arabica coffee is cultivated in the southern and northern highlands along the slopes of Mount Kilimanjaro and in the Mbeya region, where the majority of small producers are based.
Alessandro Craparo, the study's author, told the Thomson Reuters Foundation that if temperature increases follow the trend of the past few decades, coffee yields in Tanzania's highlands will likely to drop to around 200 kg per hectare by the year 2030.
"Coffee yields have declined to their lowest point in years, with many farmers in Tanzania giving up on coffee completely," Craparo said.
Temperature changes are unlikely to affect other coffee species such as Robusta, which is grown at lower altitude and is more climate-resilient than Arabica, he said.
Godsteven Maro, a soil scientist with the Tanzania Coffee Research Institute (TACRI), said falling coffee yields in Tanzania may also be related to problems such as aging coffee trees, something the Witwatersrand study acknowledges.
"To attribute the trend solely to the change in minimum temperature carries some subjectivity," he told the Thomson Reuters Foundation in an email.
According to the study, although governments in coffee producing countries have invested heavily in the coffee sector, most have not put in place strategies to adapt to climate change, putting at risk the lucrative industry and the jobs of millions of small-scale farmers who depend on coffee.
James Teri, the head of TACRI, said Tanzania's government has taken some measure to deal with the changing conditions, including advising farmer to relocate to higher altitudes in order to sustain coffee quality and quantity.
"We have also introduced new climate-tolerant coffee varieties which have been introduced to farmers in various coffee growing areas," he said.
Haji Semboja, an economics professor from the University of Dar es Salaam, warned that if adaptation to changing conditions is not effective, "the effects to livelihoods and jobs will be huge."
(Reporting by Kizito Makyoe; editing by Laurie Goering)
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