Climate change and the taste of a sip of tea
By Carolyn Y. Johnson (The Boston Globe) - February 3, 2014
Everyone knows that climate change threatens coastlines and wildlife. But its effects won’t be limited to destroying property and altering the natural world; it will also affect the quality of experiences and products we now take for granted — such as the simple ritual of sipping a cup of tea.
A group of scientists including a Tufts University chemical ecologist are exploring the effects that climate change will have on tea crops in China, supported by a four-year, $931,000 grant from the National Science Foundation.
Colin Orians, a professor of biology at Tufts, sees tea as an ideal way to study fundamental questions about plant biology, including how changing external conditions influence plants’ allocation of resources toward making defensive chemicals that protect them against being eaten.
Orians answered a few questions about the research by e-mail. His answers, edited for length, are below.
Q: When did changes in tea quality begin to be noticed?
A: It is known that the chemistry of tea shifts in response to the onset of the monsoons. What our preliminary work was able to show was that farmers perceive these changes, that the changes happen within days of the onset of the monsoon, that buyers pay substantially more for the premonsoon spring tea, and that the monsoons are arriving earlier in this area of China (Yunnan). Importantly we showed that within five days of the arrival of the monsoons, what farmers harvest has twice the biomass (plants are growing faster) but lower concentrations of some key phenolics known to be important in tea. We are in the process of more thoroughly characterizing the change in chemistry and taste, and plan to compare teas from different regions as part of the study.
Q: Would the changes be noticeable to people who aren’t very picky (i.e. drink tea out of bags)?
A: I believe many could notice the changes. . . . Our preliminary analysis of teas showed that everyone was easily able to distinguish between tea picked in the spring and that picked after the monsoons arrived. Of course bagged tea is often blended so we would expect tea companies to try new blends to limit any changes perceived by the consumers.
Q: How widespread are these issues among tea-producing regions of the world?
A: Globally, climatic conditions are becoming more and more variable and we are working with a climatologist to explore how conditions are changing in some of the key tea producing regions. I might expect the change to be highest in regions influenced by monsoons since increases in precipitation have such a large effect on tea.
Q: Typically, when people think about the effect climate change will have on agriculture, they worry about crops failing. Do you expect these changes are already occurring in other agricultural products?
A: Yes, we tend to focus so much on yield when thinking about climate change but this emphasis loses sight of the importance of quality. Is climate changing the quality of spinach, kale, or blueberries? I think we all could come up with a list of a dozen food and beverage items that we regularly consume because they are good for us. I want to know how those benefits are, or might be, changing.