The Impact of Climate Change on Tea Production & Quality

A resilient evergreen plant, Camellia sinensis has a set of requirements and preferences for soil quality, rain fall, topical environment, climate and weather pattern. Therefore, it thrives on high slopes and under
misty skies for the Chinese small leaf varietals and shaded under trees in hot and humid planes for the Assam big leaf varietals. Looking at the world map, one can see that the traditional tea-growing regions are located between the tropic of Cancer and the tropic of Capricorn, which delimit the tropical climate zone.
There are, however, some extensions into the subtropics and some tea gardens even pushing further into the temperate climate zone, such as the hilly area around Rize in Turkey; the prefecture of Saitama, north of Tokyo, in Japan; the Black Sea slopes of Georgia; the Azore Islands as Portugal’s outpost in the Atlantic; and also the recently developed tea estates in continental Europe and in the UK.
In the ancient and long-established tea producing countries like China, Laos, and Burma, where tea has been grown for millenaries, and for centuries in Japan, Korea, India, and for decades in East-Africa, Sri Lanka, and Indonesia, etc, the tea gardens were set up in areas that were well-suited for weather patterns, which allowed them to thrive after a period of rest and replenishment or after the rains. Although unforeseen weather events did occasionally occur, these remained exceptional and were usually compensated for by improved harvesting in the weeks after.
In recent and untraditional locations, the tea bush varieties that prosper have been able to adjust their agricultural requirements to the specific local climate and topography, and hence, gradually fit into growing conditions that allow to develop a valid tea economy, thus demonstrating proudly how flexible and resilient tea can be as a pioneer crop.
The growing awareness about the green house effect, the temperature calculations creating the fear of global warming, and the ever-increasing frequency of formerly unusual weather incidents, like torrential rains, sudden cold spells, long dry spells, delayed monsoon rains, and warm winters etc, have generated a need for stock taking. This first step intends to investigate ways and means to adapt, cope and respond to the adverse effects of climate change. Whilst tea farmers are used to adjusting their
ways every year according to the ups and downs of the weather, these fluctuations have become
more erratic, more intense and more frequent recently, generating concern about the short term outlook, fearing that the traditional seasonal patterns will no longer occur in a reliable way.
Considering Possible Adjustments
Since the concerns are caused by the manifold incidents of abnormal weather due to climate changes, the impacts of such unorthodox weather on tea cultivation are under close scrutiny. Whilst these meteorological incidents vary greatly from one tea region to another, they all result in adverse effects on volume and quality, and of course, on producer income and livelihood, which is particularly dramatic in
smallholder villages, where tea is often the main cash crop, namely in China, India, Kenya, and Indonesia, but also in other countries.
Professor Han Wenyan, from the Chinese Tea Research Institute in Hangzhou, underlines that the high temperatures and long-lasting draughts during the summer may finally result in a shifting of the southern tea growing areas to higher altitudes and higher latitudes, moving towards the subtropical climate zone. China is furthermore actively developing more heat resistant cultivars. The torrential rains that hit Assam in 2022 produced such an intense proliferation of pests attacking the leaves, that the bushes were severely damaged down to root systems, which most adversely affected the harvest. In Kenya’s high altitude tea-growing areas, the occurrence of unusual and long lasting cold spells, that resulted in frostbite and made the leaves unfit for harvesting, spurred research into creating more resilient and cold
resistant varietals.
Florent Weugue, a French premium tea retailer, who operates in Tokyo, Japan, underlines that warmish winters are one of the major problems in Japan: the Chinese tea varietals, which are grown here need four cold months of dormancy, which allow them to replenish their stock of nutrients from the soil, in order to flush with the arrival of warmer temperatures in the spring. Without a true cold season this does not happen and the result is that the bushes produce less buds and the leaves are lacking flavour intensity, which becomes highly detrimental to harvesting volume and to cup quality.
If there is enough space available, moving the tea fields higher up or further north is an option. Without available space, it’s the bush that needs to be adapted in order to thrive in hotter or colder, rainier or dryer climate by being more resilient. Both approaches need long term planning and in-depth research,
which will take several years before yielding any tangible results, bearing in mind the costs as a heavy financial burden. Many believe that such huge modifications and transfers should be taken to a dedicated international platform for sharing information and also obtain some government support in order to be processed successfully.
In the meantime, there are some practical and more readily available technical means, like more irrigation in dry areas, more shading in hot areas, setting up fans in the fields to break frost, more terracing to evacuate heavy rains, better weed control to keep away nasty insects, more fertilising to give the bush resistance, tight pruning to stimulate budding, more pest control to avoid massive infestation, adjusted picking rounds to preserve budding capacity.
All these aforementioned quoted measures can be carried out and be applied relatively rapidly, yet at significant costs and with the help of an available workforce. However, for many smallholders, the money and labour will require coordination and financial support from national authorities like Tea Boards or
Ministries of Agriculture.
And Still There is a Global Oversupply
All international reports state that there is a continued status of global oversupply, with tea consumption lagging behind. Although hampered by adverse climate incidents, international freight problems, trade
disruptions due to sanctions and political conflicts, ever-increasing costs of fertilisers and serious labour shortage, the annual world production of tea keeps increasing year on year. The market is dominated by China – the leading producer – supplying 49 percent of the world’s teas, and the other globally traded teas represent less than 30 percent of the world’s tea output. Although there is awareness about the
adverse impact of climate change in most national markets, there is not yet much effort deployed to investigate the challenges in a coordinated manner. The file is however under close scrutiny in the fields, in tea research laboratories, and in research institutes on national level mainly.
- Barbara Dufrêne is the former secretary general of the European Tea Committee and editor of La Nouvelle du Thé. She may be reached at: b-dufrê[email protected].