LONDON, UK [TAC] — Tea leaves picked in the hills of Sri Lanka two centuries ago may hold the genetic key to saving the global tea industry from extinction.
Researchers believe these historical samples, preserved in a UK herbarium, could help develop a climate-resilient tea crop capable of surviving increasingly severe droughts and heatwaves.
The future of the world’s most popular beverage is under threat from climate change, with longer and more frequent dry periods decimating plantations in major tea-growing nations like Sri Lanka, India and Kenya.
In Sri Lanka alone, the sector produces up to 300 million tons of tea annually and employs over 2.5 million people, putting vast livelihoods at stake.
Thamali Kariyawasam, a PhD researcher who moved from Sri Lanka to the University of Bristol’s School of Biological Sciences, is leading the charge. Her project, titled ‘Climate resilient tea: exploring the drought tolerance of Sri Lankan tea cultivars,’ aims to identify or develop new tea plants that can thrive using less water without a loss in quality.
“We are seeing tea fields being scorched by heatwaves… the biochemical composition of the tea leaf changes which can affect the taste of the cup of tea, reduce crop yields or destroy plantations entirely,” said Kariyawasam.
Tea plants are a long-term investment; saplings take two years to graduate from the nursery and can live up to 100 years. This fragility makes them extremely vulnerable to sudden extreme weather events.
A ‘time machine’ for tea
The invaluable historical resource is found at the Royal Botanic Gardens at Kew, which holds tea leaves plucked by botanists 200 years ago, when tea was first introduced to what was then Ceylon by the British.
Dr. Caspar Chater, senior research leader at Kew, described the seven million dried plant specimens in Kew’s herbarium as a “time machine.” He believes these older, hardier cultivars may hold the key, while also providing insight into how tea has adapted to past climates and diseases.
“So many livelihoods depend on tea production,” Chater noted, adding that Thamali is “dig[ging] into this past to help find solutions for the future of tea.”
The research is a crucial collaboration between the University of Bristol, the Royal Botanic Gardens at Kew, the Tea Research Institute of Sri Lanka, and the University of Peradeniya. Funding and support are also provided by Ahmad Tea, a family-run company that dedicates up to a fifth of its profits to good causes.
Zahra Afshar, Ahmad Tea’s Head of Legal, Human Rights and Sustainability, highlighted the urgency of the issue, stating there has been “astonishingly little” research on climate change’s effects on tea.
“Climate change is already affecting the cost of production and yield in tea-growing regions,” Afshar said. “We are excited to be working with the University of Bristol and Kew to keep tea crops resilient, ensure farmers stay in business and save the cup of tea as we know it.”
