The taste of tea is changing—and generally for the worse if left unmanaged," declares ethnobotanist Selena Ahmed, an assistant professor of sustainable food systems at Montana State University. Ahmed is the project lead of a research group from Tufts University in Massachusetts studying the effect of climate change on tea. And not only is flavor being compromised, but ultimately, due to erratic precipitation and extreme temperatures, "there are [fewer] areas suitable for [growing] high quality tea" around the world, she finishes.
Taiwanese farmer Alfredo Lin, a relatively new tea producer, would agree. He planted his first tea farm four years ago in Nantou County, in central Taiwan, and confirms that his crops have already experienced the effects of climate change.
"The extreme rain last year really overwhelmed my plants," he says. "It never used to be this serious. The rain is threatening the root systems."
Although Lin is new to the tea game, he’s not short of experience. Lin’s family has been growing oolong tea in central Taiwan for decades. His aunt and uncle are oolong tea producers, and his own mother works full-time as a tea picker, rising daily at 6 a.m. during the harvest season to pluck tender tea buds underneath the increasingly harsh sun. Lin calls his mother and her friends, adoringly, "mother pluckers." They are all Taiwanese women over the age of 60, and they wear long protective layers and a thick hat to prevent themselves from heatstroke in the fields.
"Young people don’t want to do this job anymore," Lin’s mother says. "It’s too much hard work. It’s getting too hot."
Lin’s crop of choice is Ruby Red #18—a highly oxidized black tea cultivar bred by the government-sponsored Tea Research and Extension Station, whose sole purpose is to improve tea plantations in Taiwan. Scientists there created Ruby Red #18 by crossing a Taiwan native variety with an Assam cultivar from Burma. The result: a wonderful brew distinguished by its cinnamon and malt sugar undertones.
"The average yield for Ruby Red tea is around 500 kilograms," explains Lin. "I only brought in 125 kilograms and 80 kilograms during my two harvests this year." Lin admits he is also afraid that the intense scorching summer heat this year will damage his plants’ buds.
"The taste of tea is changing—and generally for the worse."
"In Taiwan this spring, it was cold for a long time, and all of sudden it was hot. This decreased yields," explains David Tsay, a tea teacher who specializes in organic farming and travels around China and Taiwan giving lectures at universities. "We’re also currently waiting for the typhoon season, which is delayed this year."
These observations are not uncommon. All over the world, tea farmers are dealing with irregular precipitation and higher temperatures. In the last 15 years, global surface temperatures have been increasing; 2015 was the hottest year on record.
Too Much Rain Is Dulling the Flavor of Tea
Global warming has brought unseasonally high levels of rainfall in parts of the world. Because the atmosphere’s water-holding limit increases by about 4 percent for every one degree Fahrenheit 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 Japan, China’s Yunnan province, and Assam and Darjeeling in India. Tea plants can only take a certain threshold of rain, and in all of these areas, plants are being pushed past their precipitation limits.
"For tea, when there’s too much rain, there’s a dilution effect of the secondary metabolites," Ahmed explains, referencing the compounds that tea drinkers value—like flavor, antioxidant properties, and caffeine levels.
"Those are basically the aromatic compounds that give tea all of its flavors and really distinguishes one tea from another tea," she adds. "When it’s really wet, the plant doesn’t have the ecological cue to make these compounds, and they also get diluted."
And so while size and the weight of the tea leaves may nearly double because of the rain, the plant's major phytochemicals will decrease to about half.
Farmers Are Hiding Lower-Quality Tea
Generally speaking, all tea comes from the same plant, Camellia sinensis. But it’s the processing method a farmer follows that differentiates teas—white, black, oolong, pu’erh, red, green, yellow—from one another.
For producers of high grade green pu’erh tea in Yunnan, the quality of leaves has decreased so severely during monsoon seasons that farmers are forced to diversify their processing mechanisms so consumers won’t notice the drop in tea quality. If they don’t, the prices of the tea will sink.
"It never used to be this serious."
So, that means, instead of making green pu’erh, these producers are opting for oolong and black teas during the monsoon season instead. Oolong and black tea require heavy processing methods and undergo more fermentation than green pu’erh. The fermentation process covers up some of the aromatic imperfections of the raw leaf. "With green pu’erh, it’s hard to hide the decrease in quality," Ahmed says. "With oolong or black tea, you can sort of cover up some of the issues in the growing conditions in the ecosystem itself."
Temperature Fluctuations May Mean Less Tea
Beyond rainfall, in places like Zhejiang and Fujian in eastern China and Taiwan, the biggest hurdle tea producers must overcome is temperature variability.
This spring in Zhejiang, where the famous Longjing green tea (Longjing, or Dragon Well, refers to the area in Hangzhou—the capital of Zhejiang—where, arguably, the best green tea in China is produced, also a favorite of the Qianlong Emperor) grows, the weather was warm enough to cause an early bud burst. It was followed up by frost, which ended up damaging some plants. Although this didn’t affect tea quality, it did impact yield. Zhejiang tea farmers weren’t able to harvest as much tea compared to previous years.
"The early budding also impacted the harvest schedule," Ahmed says. "It was difficult getting laborers to harvest the tea last-minute this year."
How to Save Tea
Ahmed offers several suggestions on how farmers can best protect their tea plants from climate change, but first and foremost, she believes that plants which grow in a diversified ecosystem have the best chance to withstand weather changes and produce high quality leaves. Right now, the majority of tea farms around the world exist as monocultures, which makes them more susceptible to unpredictable weather patterns.
"Traditionally in southwestern China, tea plants were grown in a forest ecosystem," Ahmed explains. "This multistoried structure, or agroforest, helped manage pests and diseases." Agroforests are also more resilient to weather changes and erratic rainfall.
Next, she notes that organic farming yields higher quality plants compared to conventional farming. "We studied quality from organic farms at sites in Fujian and Zhejiang," she says. "Organic teas have higher phytochemicals." Simply put: organic teas taste better. This is most likely because organic tea plants live under greater stress than conventional tea plants since farm managers don't apply the same amount of pesticides, fertilizers, and other chemicals to protect them. Under stress, organic plants produce more phyochemicals. Additionally, strong pesticides used in conventional farming strip the soil and shortens the lifespan of a tea bush to a couple of years versus a couple of decades.
And finally, for sites that are susceptible to erosion from heavy rainfall, Ahmed advises farmers to plant their crops from seed. "The plants grown from seeds or seedlings have stronger roots," she says. Clonal propagules, or trees planted from cuttings, aren’t able to dig as deep and absorb nutrients from the soil and water.
While the future of tea may seem bleak, on the contrary, some parts of the world may actually be benefitting, and even producing higher quality tea, as a result of climate change.
"A little bit of drought is actually good for tea quality," admits Ahmed. "It creates complex flavored teas, but if it’s too extreme, this is detrimental to the tea plant." She notes that there was a drought in southwest China in 2012 and 2013. In Yunnan, pu’erh producers were able to charge higher prices for their drought-ridden product—which had a more full-bodied and intense taste.
Tea as a Case Study
It’s difficult to pinpoint flavor subtleties in crops like wheat and rice. But tea, with its hundreds of compounds, is sensitive and complex enough to reflect minute changes in temperature and precipitation.
In the last 15 years, global surface temperatures have been increasing; 2015 was the hottest year on record.
Although weather fluctuations are normal in any ecosystem, these variables have been especially unpredictable in the last 15 years. What’s taking place with tea is a sobering microcosm for what’s happening to agricultural products around the world. "Tea is really an indicator species for climate change," Ahmed says. "It has all of these variables and makes for a really good case study."
Master tea connoisseurs, she points out, are able to drink a cup and relay the different environmental conditions in which a leaf was grown. Tsay, the tea teacher in Taiwan, is one of those people. He works with farmers across Taiwan and the greater China region to transition to organic farming. He’s a staunch advocate for the preservation of wild tea trees and agroforests in Yunnan.
"You can immediately notice the difference in taste when people cut corners," he states. "When farms blindly pursue yield, quality is at risk."
That, it seems, is the entire crux of the climate change conversation. While yields may decrease based on factors like temperature fluctuations, for tea enthusiasts, the quality of the tea is the most important component. And quality, according to Ahmed and her team, can best be maintained by diversifying planting systems.
"We need to think about ways of having our agricultural system like a naturally functioning ecosystem," Ahmed adds. "More consumers these days are aware of organic and sustainable food systems. The next step is developing a climate smart system."
Editor: Kat Odell