More than half of the world's wild coffee species could be wiped out because of climate change and other factors, according to a new study that raises concerns about the future of global coffee production.

Scientists at the Royal Botanic Gardens, Kew in southwest London, carried out an International Union for Conservation of Nature Red Threatened Species assessment on 124 coffee species.

The newly published research revealed that 60 percent of all wild coffee species are threatened with extinction because of deforestation, climate change, and the spread and increasing severity of fungal pathogens and pests.

Those in serious jeopardy include the wild relative of Coffea arabica, one of the world's most popular and widely traded types of coffee. It is in trouble largely due to the impacts of climate change.

The findings of the study have been published in leading research journals Science Advances and Global Change Biology.

Aaron Davis, head of coffee research at Kew and lead author of the paper, said: "Among the coffee species threatened with extinction are those that have potential to be used to breed and develop the coffees of the future, including those resistant to disease and capable of withstanding worsening climatic conditions. ... Targeted action is urgently required in specific tropical countries, particularly in Africa, to protect the future of coffee."

Kew scientists spent two decades conducting the research, with much of the work undertaken in the wild locations where coffee grows, mainly in the remote forests of Africa and on the island of Madagascar.

In Ethiopia, the birthplace of the Arabica coffee bean and Africa's largest coffee exporter, climate change is one of the greatest longterm threats to coffee farming.

In 2012, Kew researchers and their collaborators were able to project how a changing climate might affect the species in Ethiopia by using computer modeling. They found the number of locations where Arabica grows could decrease by as much as 85 percent by 2080.

In 2017, the Kew-Ethiopia team looked into the influence of climate change on coffee farming and discovered that up to 60 percent of the land used for the country's coffee production could become unsuitable for use by the end of the century.

Coffee production provides a livelihood for 15 million Ethiopians and the annual export is valued at $1 billion.

Eimear Nic Lughadha, senior research leader in Kew's Conservation Department and lead scientist with Kew's plant assessment unit, said: "Some of the coffee species assessed have not been seen in the wild for more than 100 years, and it is possible that some may already be extinct. We hope this new data will highlight species to be prioritized for the sustainability of the coffee production sector, so that appropriate action can be taken to safeguard their future."

Kew scientist say current conservation measures are not good enough to ensure the long-term future of one of the world's favorite beverages.

Figures from last year found the United Kingdom's coffee consumption grew to 95 million cups a day, from 70 million in 2008.

Researchers said Kew's work was not undertaken to show the bleak prospects for crop species, such as the Arabica coffee, but to understand risks, so the right intervention and planning measures can be put in place.

Davis said: "We hope our findings will be used to influence the work of scientists, policy makers and coffee sector stakeholders to secure the future of coffee production-not only for coffee lovers around the world, but also as a source of income for farming communities in some of the most impoverished places in the world."

One coffee species, thought to be lost, was discovered in December.

Coffea stenophylla, otherwise known as the Highland Coffee of Sierra Leone, has not been seen in the wild since 1954 and has all but disappeared from coffee plantations and botanical gardens.

Aaron Davis and Jeremy Haggar from the University of Greenwich went to Sierra Leone to look for the species after other stakeholders failed to locate it.

While many of the original forest sites for the plant have long been lost, the team found a single plant at a previously known location and then found more plants in a new location. Both sites are severely threatened by deforestation and human encroachment.

It's not yet known what influence species like Coffea stenophylla will hold for the future of global coffee production.

Kew experts warned that wild coffee species are needed because they support the prospect of developing a resilient and sustainable coffee production sector.

Craig Hilton-Taylor, head of IUCN Red List Unit, said: "The numerous wild relatives of the commercially grown crops, such as Arabica coffee, are essential to ensure the resilience of cultivated coffee in the face of climate change and other threats ... There is mounting evidence that climate change is affecting many crops, not just coffee. The situation is alarming and is an important reminder of the need for effective species conservation."