A cup of morning coffee could be much harder to find, and much more expensive, before the century is out thanks to climate change and the possible extinction of wild Arabica beans.

That’s the warning behind a new study by U.K. and Ethiopian researchers who say the beans that go into 70 per cent of the world’s coffee could be wiped out by 2080.

Researchers at the Royal Botanic Gardens in Kew and the Environment and Coffee Forest Forum in Addis Ababa, Ethiopia looked at how climate change might make some land unsuitable for Arabica plants, which are highly vulnerable to temperature change and other dangers including pests and disease.

They came up with a best-case scenario that predicts a 38 per cent reduction in land capable of yielding Arabica by 2080. The worst-case scenario puts the loss at between 90 per cent and 100 per cent.

There is a "high risk of extinction" says the study, which was published this week in the academic journal Plos One.   

That would be bad news for both coffee drinkers and coffee-producing countries such as Ethiopia, Brazil and Colombia, which in 2009/2010 shipped some 93 million bags of coffee around the world, worth an estimated $15.4 billion.

Most coffee is made from Arabica beans. They are prized for their genetic diversity and grow best at between 18 C and 21 C. Above that, the plants ripen too quickly — which affects taste — or grow too slowly. Other coffee stems from Robusta beans.  

The study goes on to note that its results are "conservative" because it did not take into account the large-scale deforestation of the Arabica-suitable highland forests of Ethiopia and South Sudan.

"The models assume intact natural vegetation, whereas the highland forests of Ethiopia and South Sudan are highly fragmented due to deforestation," the researchers wrote. Pests, disease and other factors were also not considered.

The authors of the report say certain "core sites" capable of yielding Arabica until at least 2080 should be set aside for conservation.