How 200-year-old tea leaves could help breed climate-resilient tea

Record ID: 2359221

  • Title: How 200-year-old tea leaves could help breed climate-resilient tea
  • Date: 26th February 2026
  • Summary: WINCHESTER, ENGLAND, UK (JANUARY 26, 2026) (Reuters) VARIOUS OF TEA TASTERS FROM AHMAD TEA  ROWS OF TEA SAMPLES LINED UP / TEA TASTER SAMPLING TEA TEA SAMPLES PREPARED FOR TASTING VARIOUS OF TEA TASTER SAMPLING TEA USED TEA LEAVES NEXT TO CUP TEA TASTER SAMPLING TEA VARIOUS OF ZAHRA AFSHAR FROM AHMAD TEA TASTING TEA (SOUNDBITE) (English) ZAHRA AFSHAR, HEAD OF LEGAL, HUMAN
  • Embargoed:
  • Keywords: Ahmad Tea Kew Gardens Royal Botanic Gardens at Kew THAMALI KARIYAWASAM University of Bristol climate change tea tea crop
  • Location: BOGAWANTALAWA & TALAWAKELLE, SRI LANKA /  LONDON & WINCHESTER, ENGLAND, UK
  • City: BOGAWANTALAWA & TALAWAKELLE, SRI LANKA /  LONDON & WINCHESTER, ENGLAND, UK
  • Country: UK
  • Topics: Climate Adaptation and Solution,Climate Change,Environment,Europe,General News
  • Reuters ID: LVA002727804122025RP1
  • Aspect Ratio: 16:9
  • Story Text: A University of Bristol researcher is turning to tea leaves collected in Sri Lanka about 200 years ago in a bid to help protect one of the world's most consumed beverages from the growing toll of climate change on plantations.
    The project, led by Sri Lankan scientist Thamali Kariyawasam, is analysing historic tea specimens preserved at the Royal Botanic Gardens, Kew, alongside modern cultivars to understand which varieties cope better when water is scarce.
    "The project that I'm working on investigates the impact of climate change on tea, Camellia sinensis," Kariyawasam told Reuters, focusing on how drought and prolonged dry periods are affecting the crop.
    Kariyawasam is building a time series from the 1800s to the present, combining anatomical measurements with biochemical and genetic analysis.
    "The historical samples that are preserved in the herbarium… I'm trying to create a time series back from 1800s up to today and see how the plant has been changing over the time," she said, including shifts in water-use efficiency that she said can be quantified using carbon isotope signatures, alongside DNA work to track genetic change.
    The research is a collaboration between Bristol, Kew, Sri Lanka's Tea Research Institute and the University of Peradeniya, with support from British tea brand Ahmad Tea.
    Zahra Afshar, Ahmad Tea's head of legal, human rights and sustainability, said growers were grappling with fast-changing conditions.
    "That predictability of rainfall and temperature is just changing so much," she said, adding suppliers were having to invest in more climate-resilient farming.
    Tea is a long-lived crop with high exposure to weather shocks: saplings can take about two years to move from nursery to field, and bushes can live for decades, meaning farmers can lose years of investment if young plants die or heat and drought wipe out mature fields. Erratic rainfall can also erode soils and alter leaf chemistry, affecting yields and the taste profile that helps determine prices.
    "Quality is affected because the soil becomes eroded when there's really heavy rainfall and obviously the heat from the sun can also damage the soil and also burn the top of the leaves," added Afshar.
    Kew scientist Caspar Chater said the herbarium's collections provide a way to link crop genetics with how plants responded to past climates.
    "If we can overlay the genetics of the crop on the historic climate change that that crop has experienced, we'll be able to see how these teas have locally adapted," he said, helping pinpoint genes tied to resilience.
    They said the aim is to turn the findings into practical guidance for growers - identifying drought-tolerant traits and cultivars that can "do more with less water" - and to share that toolkit beyond Sri Lanka with tea producers in places such as India and East Africa.
    "I think this information would be vital for the tea breeders in all the tea growing countries to create a better and more resilient crop in the future," said Kariyawasam.
    Sri Lanka's "Ceylon tea" sector is central to the island's export economy, and the broader industry is watching for tools to protect supply as producers in major growing regions report more erratic weather.
    (Production: Matt Stock)
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