YUNNAN, China — A study funded by the National Science Foundation will investigate changes in temperature and rainfall patterns that are believed to alter not only the taste and aroma but also the potential health benefits of tea.
Science Daily reported this week on a research project by Tufts University biologist Colin Orians to “examine how climate change affects the concentration of chemical compounds that are responsible for tea’s stimulant, sensory and healthful properties.”
The study is based on preliminary research conducted in southwestern China’s Yunnan Province by co-principal investigator and tea expert Selena Ahmed while she was a graduate student and later Training in Education and Critical Research Skills Program (TEACRS) postdoctoral fellow at Tufts.
“Since the quality of tea is determined by a range of secondary chemicals that depend on climatic conditions, climate change can have significant consequences for tea markets,” says Orians, a professor in the Department of Biology in the School of Arts and Sciences at Tufts. “People buy and drink tea for certain qualities. If those qualities are not there, then they may not buy the tea.”
Similar research is ongoing in Assam, India where R.M. Bhagat, deputy director of the Tea Research Association, based in Tocklai told Al Jezeera that “the degree of impact varies regionally, depending on distance from equator and other local conditions.”
The Tocklai tea experimental station has been recording daily weather and tea production data for more than 100 years. “We have found that the minimum temperature has risen by 1.5 degree centigrade, and the annual rainfall has reduced by 200 millimeters,” said Bhagat.
Bhagat says tea trees in Assam previously would be high yielding until 40-45 years of age, but now decline at 30-35. The resulting tea is less pungent and full-bodied. Assam was historically viewed as sub-tropical with an ambient temperature under 95º Fahrenheit (35º Celsius). The range is now 100º to 104º (38-40º C) in shaded areas, and upwards of 122º F. (50º C) in non-shaded spots. Photosynthesis slows at 95º F. and food production in the plant stops above 102º F. Tea leaves can no longer breathe and die above 104º F.
“Only time will say whether the tea trees will adapt or not, but the industry has to gear up,” he says. He recommends increasing shaded areas, alternative water systems, and using organic manure. The association is also testing clones that are resistant to climate change, he adds.