If you aren’t convinced by the shrinking glaciers, rising temperatures, and extreme weather events, there’s now another reason to start reducing our greenhouse emissions much faster. And that’s the negative effect climate change is having on the world’s tea production, affecting not only its yield but also its flavor.

Tea plants are very sensitive to the environments in which they are grown — so much that experts can distinguish different tastes based on where the tea is grown. But that sensitivity is also what makes the crop vulnerable to climate change. Variations in temperature and precipitation can alter tea yield as well as its balance of chemicals.

A report by the charity Christian Aid argues that some of the world’s biggest tea-growing areas will be severely hit by extreme weather, with their yields set to be reduced if the climate crisis continues at its current pace. Floods, droughts, heatwaves, and storms (all of which can be exacerbated by climate change) are already having diverse effects on tea production around the world.

The report focused on Kenya, China, India, and Sri Lanka, the world’s largest tea-producing countries in the world. Kenya is the biggest exporter of black tea in the world and for many years it had the perfect climate for tea growing, with long sunny days. But now climate change is bringing erratic weather changes that pose a threat to tea producers.

A study found that climate change is going to slash optimal conditions for tea production in Kenya by a quarter (26.2%) by 2050. This decline in production is already being felt by Kenyan tea growers. In a survey of 700 farmers in all seven of Kenya’s tea-growing regions, almost half said to have noticed changes in rainy and dry seasons.

A similar situation is being experienced by China, the world’s largest tea producer, which supplies the world with over 300 thousand metric tons of tea annually. Tea in China is regularly produced in the provinces towards the south and east of the country where the weather is humid and changes from tropical to subtropical.

“Climate change is reducing tea yields in China, with changes to weather patterns over the past 50 years affecting crop growth, quality and chemical composition of tea leaves, according to previous studies by US researchers. Longer monsoon seasons with heavier daily rainfall have been linked to crop losses,” the researchers wrote.

The report also looked at India, the second-largest tea producer. More than half of it is produced in the northeast region of Assam, the largest single tea growing region in the world. North Bengal in the Darjeeling district is another major tea-growing area. However, climate change is already threatening tea production in these regions.

In a survey of producers in Assam, 88% of plantation managers and 97% of smallholders stated that the challenging climate conditions were a definite threat to the growth and production of tea. Furthermore, climate change has caused erratic rainfall which has led to both droughts and heavy rain in Assam, the report showed.

Not just yield

The researchers at Christian Aid raised their concern not only about the declining tea production because of climate change but also on tea losing some of its many properties, including flavor. Tea has a set of aromatic compounds known as “secondary metabolites” that allow to differentiate one tea from another.

However, when tea plants get really wet they suffer a double effect because the plants stop having the ecological cues to make these metabolites, and the few that are there get diluted as the plant gets waterlogged. Global warming has brought unseasonably high levels of rainfall in many parts of the world.

Because the atmosphere’s water-holding limit increases by about 4% for every 0.6ºC rise in temperature, extreme precipitation is more likely when a storm passes through a warmer atmosphere holding more water. These places include major tea-producing areas like China’s Yunnan province, Assam, and Darjeeling in India, among others.

The study also warned over tea losing some of its many benefits to human health because of climate change, such as its ability to boost the immune system, fight off inflammation and prevent cancer – also keeping us alert during the day. Studies have shown that climate change is expected to result in lower quality and less healthy tea in the future.

Christian Aid is calling countries to increase their climate action over the course of the year, especially thinking about the upcoming climate summit COP26 in the UK, a tea-drinking nation. The organization also wants rich countries to provide poor regions with financial assistance to help them cope with the impacts of climate breakdown.