The familiar taste of tea is under threat from climate change, which could deliver a more bitter flavour to the nation's much-loved cuppa, campaigners warn.
A report published by aid agency Christian Aid warns that rising temperatures and worsening weather extremes in countries such as Kenya, India and Sri Lanka could make tea more bitter and harsher with less consistent flavours.
Even tea growers in the UK are experiencing climate change that they warn is making it much harder to achieve consistent flavours.
And disruptions to harvests caused by the changing climate are likely to cause price spikes, rising costs and unreliable supplies of the staple British drink.
Christian Aid also warns the biggest impact is on smallholder farmers and tea producers in the countries where tea is grown who are being hit by climate change, along with issues including the rising price of fertiliser and fuel as a result of the war in Iran.
Action to protect the cuppa
The charity is calling for action to support farmers, including developing more resilient tea plants, improving irrigation and planting shade trees to protect the bushes, as well as fair pricing, funding for producers to put in measures to help them adapt to climate change and protections for workers.
The report warns that tea production relies on stable temperature and rainfall conditions, which are now shifting in producer nations, with optimal growth within a relatively narrow temperature range of between 13C and 30C and with adequate but not excessive rainfall.
Dr Neha Mittal, senior climate services scientist at the UK Met Office and visiting scientist at the University of Leeds, said: "Tea brands depend on delivering a stable and recognisable flavour profile.
"As climate variability increases, achieving that consistency becomes more challenging."
Tea flavours and quality depend on a balance of compounds such as catechins, amino acids and polyphenols, according to the report, but higher temperatures increase the production of more astringent compounds while reducing sweetness, leading to a more bitter taste.
Erratic rainfall can dilute compounds that give tea its depth and character, while extreme weather from droughts to floods and worsening crop pests in warmer conditions can also put pressure on the plants, leading to lower yields, lower quality and more bitter crops, the report says.
"The result is a simple but unsettling prospect – the familiar taste of the British cuppa, smooth, balanced, reliable, is becoming harder to guarantee," it warns.
Consistency needs consistency
Claire Nasike Akello, climate adaptation and resilience lead at Christian Aid, said: "For generations, consumers have taken for granted that a cup of tea will taste the same, day in, day out.
"But that consistency depends on a stable climate, and that stability is now breaking down.
"What we are seeing is the beginning of a shift towards a harsher brew, with the risk that Britain’s favourite drink becomes more bitter, more expensive and less reliable."
And she warned that farmers who had done least to cause climate change were being pushed further onto the frontline of the crisis, with fewer resources to adapt.
"Protecting the future of tea means investing in people as well as crops – through fair pricing, targeted adaptation finance and stronger support for farmers and workers," she urged.
Reuben Korir, a small-scale tea farmer from Kericho County in Kenya, said that when the weather was very dry or unpredictable, the quality of the tea changed.
"The leaves are smaller, and we believe the taste is not as good as it used to be during more stable seasons," he said.
"Rains no longer come when expected, and dry periods last longer.
"Harvests are not predictable anymore, and neither is the income."
Even in the UK, the changing climate is a problem for tea producers, they say.
Lucy George, who runs Peterston Tea, a small tea farm in South Wales and one of the first commercial tea farms in the UK, said: "Seasons are less predictable with warmer winters, sudden late frosts, and irregular rainfall patterns."
For the farm, warmer periods could accelerate growth, while erratic rainfall or cold snaps could slow growth and affect leaf structure.
"The balance that gives tea its depth – sugars, amino acids, polyphenols – is closely tied to stable growing conditions.
"When that stability is lost, consistency becomes much harder to achieve," she said.
