Approximately 100m farmers around the world depend on coffee for a living; and so do the economies of several countries. But global warming now poses an existential threat to coffee cultivation.
Regardless of pronouncements of targets by governments, the financial markets have priced in an increase in global temperatures north of 3°C. This is based on the values of current investments and loans relating to the carbon economy. This prediction kills coffee as a cash crop, indeed anything over 2°C would do the same.
The coffee market is dominated by coffea arabica and coffea canephora (also referred to as robusta). Arabica does not cope well with temperatures over 22°C and canephora doesn’t cope well over 24°C. There are over 122 other species of coffee but they don’t taste as good, the beans are smaller, and the yields are poorer.
Looking to the past can sometimes provide risk solutions, so it can be worth the effort. Researchers at Kew Gardens have come across a document written by Scottish botanist, George Don, in 1834. It describes a species of coffee, coffea stenophylla, grown in Sierra Leone that Don found superior in flavour to arabica. It was farmed in that region up until the 1920s, then gradually forgotten. Not only does it taste as good if not better than arabica, it can withstand far higher temperatures.
The team at Kew, along with an agricultural research centre in France, tested stenophylla to see if Don’s claim about its flavour was true. They arranged a blind tasting with 18 professional coffee tasters, 15 of whom thought that the stenophylla they were tasting was arabica.
There is now at least the possibility of cultivating stenophylla directly or cross-breeding it to give existing, higher yielding coffees increased heat resistance. This became possible by looking back in time for a simple solution that was waiting to be found.
Data Sources: parliament.tv, The Economist magazine