Introduction

Teas made of the tender leaves and buds of the species Camellia sinensis (L.) O. Kuntze, is the most widely consumed beverage in the world, with its popularity steadily increasing year after year (Tamang, 2008). Approximately 5.1 million tonnes of tea are produced annually, with over 1.8 million tonnes exported each year (Munasinghe et al., 2017). Tea cultivation is confined to specific regions of the world, primarily in tropical and subtropical areas, where the precise climate and soil conditions necessary for its growth are met (Majumder et al., 2010; Pan et al., 2022). The tea plant is native to East Asia and thrives in these regions. Currently, over 60 countries cultivate tea trees in tropical and subtropical regions, and there are approximately 3 billion tea drinkers worldwide (Pan et al., 2022).

Most tea-producing countries are in Asia, with China, India, and Sri Lanka leading. In Africa, major producers include Kenya, Malawi, Rwanda, Tanzania, and Uganda, mainly in tropical regions (Chang, 2015; Majumder et al., 2010). Tea cultivation and consumption have also expanded to other Asian countries, including Korea, Japan, and Vietnam (Pan et al., 2022). China is the world’s top producer, consumer, and exporter of tea, producing 14.5 million tonnes in 2022 (Table 1), which accounts for 48.9% of global tea production according to the Food and Agriculture Organization. After China, India is the second-largest tea producer, contributing roughly 20.1% of the global total (FAOSTAT, 2024; Jagadeesh et al., 2024; Wu et al., 2020). Kenya and Sri Lanka follow as the next leading producers (Bhagat et al., 2016; Kumar et al., 2021).

Korea is the thirty second tea producing country in the world with the production of 4,061 tonnes in 2022 (Table 1). The primary tea-growing regions are Boseong of Jeollanam-do, Hadong of Gyeongsangnam-do, and Jeju Special Self-Governing Province, with the tea market expected to grow annually by 4.59% (Hassan et al., 2023). As one of the most important crops in these countries, tea industry significantly contributes to the gross national product, reducing poverty, and providing employment in tea-producing regions (Mukhopadhyay and Mondal, 2017).

Tea is classified into two well-known botanical varieties: C. sinensis var. sinensis (small leaved China type) and C. sinensis var. assamica (broad leaved Assam type) (Borthakur et al., 2023; Pan et al., 2022; Raman, 2021). The C. sinensis variety grows as large shrubs with thick, hardy, and very small leaves that can withstand low moisture, stress, and frost. In contrast, C. assamica variety is a small tree with sturdy branches and is characterized by its thin, glossy, and large leaves, which are sensitive to drought and cold. The diversity of teas arises from differences in type (such as white, black, green, matcha, post-fermented, and oolong), variety (whether blended and unblended) and processing methods, including cut, tear, and curl (CTC)) (Peterson et al., 2004). Fig. 1 illustrates the variety of teas based on their different processing methods. In recent decades, tea has garnered increasing attention due to its reported health benefits, particularly for its antioxidant properties, as well as its potential anticarcinogenic and antiarteriosclerotic effects (Wang et al., 2000). Various studies confirm that these health benefits are primarily due to the presence of flavonoids, such as catechins and flavonol glycosides. The major catechins in tea are (−)-epigallocatechin gallate, (−)-epicatechin gallate, (−)-epigallocatechin, and (−)-epicatechin which also contributes to the tea’s sweet aftertaste, bitterness, and astringency (Fang et al., 2021; He et al., 2021; Liao et al., 2022; Punyasiri et al., 2004; Song and Chun, 2008; Wang et al., 2000).

Fig. 1

Illustration of types of tea based on different processing methods.

Climate change refers to the alteration of climate patterns across various regions worldwide (Etukudoh et al., 2024; Raihan, 2023). Numerous studies have reported that human activities, such as deforestation, extraction and combustion of fossil fuels, and industrial processes, have increased the earth’s temperature, leading to global warming and severe consequences in different parts of the world (Kaiho, 2023; Ruv Lemes et al., 2023; Trout et al., 2022; Vargas Zeppetello et al., 2020; Yoro and Daramola, 2020). Climate change also impacts millions of lives through natural disasters such as floods, droughts, and storms (Cui et al., 2022; Wasko et al., 2021). Additionally, climate change affects multiple sectors, including agriculture, health, and the environment (Ebi et al., 2021; Ebi and Hess, 2020; Li et al., 2022; Liaqat et al., 2022; Malhi et al., 2021; Raihan, 2023; Rawat et al., 2024). Effects like rising temperatures, rising sea levels, changes in precipitation patterns, drought, and floods have been reported to have adverse impacts on various crops (Agnolucci et al., 2020; Venkatappa et al., 2021). In recent years, concerns have grown about the impact of climate change on tea production in both major and minor tea-producing regions around the world, such as China, India, Sri Lanka, Kenya, Nepal, Turkey, and Korea (İzmirli and Gül, 2023; Jayasinghe and Kumar, 2020; KOSIS, 2024; Muench et al., 2021). Previous studies showed that both heat and cold extremes resulted in reduced tea production in China, the largest tea producing country. Particularly, extreme cold reduced the annual tea production by 56.3% (Mujahid Hilal, 2019; Yan et al., 2021). Additionally, the altering temperature and precipitation patterns have disrupted tea production in the four major tea producers (Baruah and Handique, 2021; Jayasinghe and Kumar, 2020; Muoki et al., 2020; Rigden et al., 2020). Furthermore, between 2008 and 2011, cold shock due to climate change was particularly pronounced in Korea and Japan. However, in 2011, the severity of cold shock during the spring season was greater in Korea than in Japan (Lee, 2015). In Korea, frequent low temperatures, drought, and strong winds during the winter season from December 2010 to February 2011 increased frost damage in tea plants in major tea producing areas like Jeollanam-do and Gyeongsangnam-do. This low-temperature occurrence led to 80% frost damage in 2018 and 26% in 2021, resulting in a decrease in tea production of 8% and 15%, respectively (Hwang and Kim, 2012). This impacts the economy of the countries whose economies are predominantly based on agriculture (Muoki et al., 2020).

This review aims to assess the current status and future prospects of how tea plants respond to climate change. The present study will examine the impacts of climate variability on tea production, including alterations in growth, yield, and quality, across various regions. Furthermore, the main aim of this review is to summarize current knowledge on how tea plants respond to climate stressors and to explore current knowledge on adaptive strategies and innovations that could support the sustainability of tea cultivation under changing environmental conditions.

Climate Change and Its Impact on Tea Cultivation

1. Overview of climate change

Climate change refers to the long-term alteration of temperature and typical weather patterns. It encompasses changes in various climatic factors, such as temperature, precipitation, and atmospheric carbon dioxide (CO₂) levels, which significantly impact ecosystems worldwide (Niles and Mueller, 2016; Rajan et al., 2024; Rummukainen, 2012). According to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report, the average global temperature from 2001 to 2020 has risen by about 0.99°C above pre- industrial levels (1850－1900). Alongside this warming, climate extremes have notably shifted, with more frequent and intense heat and increased heavy precipitation in most regions worldwide (Masson-Delmotte et al., 2021; Seneviratne et al., 2021). A report by the IPCC states that global warming is primarily caused by human activities and is very likely to reach 1.5°C between 2021 and 2040 (Masson-Delmotte, et al., 2019).

In order to predict changes in tea tree cultivation areas due to climate change in Korea, we analyzed the potential tea tree growing areas by applying SSP45 and SSP585 scenarios. As a result, the potential tea tree growing areas expanded to the south coast, west coast, and east coast in both scenarios. Furthermore, if carbon emissions are more severe than the current level, the areas with high growth potential for Korean tea trees are expected to expand further, greatly expanding the cultivation areas (Kim, et al., 2023).

Asia is the most populous subcontinent, and it is particularly vulnerable to the effects of climate change, and these impacts are expected to intensify in the future (Habib-ur-Rahman et al., 2022; You et al., 2022). The agriculture sector is likely to experience varied adverse effects from climate change, given the diversity of farming and cropping systems that rely heavily on climate conditions (Habib-ur-Rahman et al., 2022). In China, the world’s largest tea producer, extreme climate events like heatwaves have caused significant damage, leading to direct economic losses of approximately 59 billion RMB (Sun et al., 2014). As global temperatures continue to rise, driven largely by human activities, it is crucial to develop adaptive strategies to mitigate the escalating risks associated with climate change, particularly in vulnerable regions.

2. Direct and indirect impacts of climate change on Tea plants

Tea is a climate-sensitive plant, primarily grown in tropical and subtropical regions at elevations below 3000 m where specific climatic conditions are met (Mallik and Ghosh, 2023). In recent decades, climate change has affected tea production in various regions around the world (Beringer et al., 2020). These impacts can be divided into two categories: direct and indirect effects on tea plants. Direct effects include temperature changes that cause heat stress or frost damage (Kotikot et al., 2020; Samarina et al., 2020; Yan et al., 2021). High temperatures can lead to deterioration of tea quality, while frost can cause physiological and structural damage to leaves and buds, leading to lower yields (Han et al., 2017; Kotikot et al., 2020; Larson, 2015; Lu et al., 2019; Samarina et al., 2020; Wang et al., 2023). This extreme weather can lead to reduced photosynthetic efficiency and enzyme activity, and causes water loss, imbalance metabolism and stunted growth (Hajiboland, 2018; Han et al., 2020; Lu et al., 2019; Yan et al., 2021). Altered precipitation patterns, such as prolonged droughts or excessive rainfall, directly impact tea plant health by causing water stress or waterlogging, respectively (Qian et al., 2018; Rigden et al., 2020). Water stress during droughts reduces tea leaf production and quality, while waterlogging can lead to root diseases and nutrient leaching (Ahmed et al., 2018; Hasan et al., 2023; Wijeratne, 1996). Indirect impacts involve changes in pest and disease dynamics due to shifting climate conditions. Warmer temperatures and increased humidity can lead to higher incidences of pest infestations and diseases, further threatening tea cultivation (Jayasinghe and Kumar, 2019; Muoki et al., 2020; Pandey et al., 2021). As the climate changes, these impacts are likely to become stronger, making it important to adopt sustainable farming practices.

3. Impact on tea growing regions

According to the Food and Agricultural Organization’s (FAO) database, among 20 major tea-growing countries in the would, 11 are in Asia, eight are in Africa, and one is in Latin America (Durighello et al., 2021; Jayasinghe and Kumar, 2020). Table 1 outlines the major tea-growing regions, detailing their production quantities and the percentage change in production over the past two decades, specifically between 2010 and 2011, and between 2021 and 2022 (Annual bulletin of statistics, 2022; FAOSTAT, 2024). In 2011, several key tea-producing countries, including China, India, and Vietnam, experienced production increases of approximately 12.08%, 10.53%, and 5.32%, respectively, compared to 2010. Conversely, other significant producers such as Kenya, Sri Lanka, Turkey, Indonesia, and Korea saw decreases in production of 5.30%, 0.56%, 5.70%, 2.59%, and 6.33%, respectively. Additionally, minor tea-producing countries reported an overall reduction of 3.91%. By 2022, China, India, and Vietnam again recorded production increases of 5.61%, 1.79%, and 2.35%, respectively, compared to 2021, although these increases were lower than those observed in the previous decade. In contrast, major producers like Kenya, Sri Lanka, Turkey, Indonesia, and Korea faced substantial declines in production, with reductions of 23.73%, 22.22%, 10.34%, 0.66%, and 0.51%, respectively. Minor tea-producing countries also reported a decline of 4.95%, marking a further decrease compared to 2011. Overall, tea production has declined at a greater rate in the current decade than in the previous one. Climate change poses a significant threat to global agriculture, particularly in regions like Asia, where diverse farming systems rely heavily on specific climate conditions (Arefin and Hossain, 2022; Habib-ur-Rahman et al., 2022; You et al., 2022). As a result, each tea-producing region faces unique climate challenges exacerbated by these environmental changes. These reductions in tea production may largely be attributed to these climate-related issues.

The southwestern China and its adjacent areas are the origin of the world’s tea plants and it’s growing areas range from Hainan Island at 1848’N to Shandong at 3604’N, and from Nyingchi in Tibet at 94 15’E to Taiwan at 121 45’E, with tropical, subtropical, and warm temperate climate (Durighello et al., 2021). The largest tea planting regions in China include Guizhou, Fujian, Hubei, Sichuan, and Yunnan, while the major yields are from Fujian, Yunnan, Sichuan, and Zhejiang (Durighello et al., 2021; Xiao et al., 2018). In China, rising temperatures and altered precipitation patterns are leading to increased heat stress and drought impacting tea yield (Lou et al., 2021; Yan et al., 2021). Studies demonstrated that rising temperature and drought due to global warming negatively affects tea production in Zhejiang province, China (Jayasinghe and Kumar, 2021; Lou et al., 2021). Additionally, the uneven distribution of rainfall has led to a significant decline in tea output across the country (Boehm et al., 2016). Furthermore, a privious study shows that tea crops in Fujian province, eastern China is under higher risk from cold stress than heat stress (Cao et al., 2024). Additionally, tea yield and quality are significantly impacted by the increased outbreak of pests and diseases driven by climatic warming and extreme shifts in water availability. Rising temperatures accelerate the emergence of pests and diseases, leading to more frequent pest generations (Ahmed et al., 2014a, 2014b; Ye et al., 2014; Zhao et al., 2022).

In India, the main tea-growing regions are in North India (located between 22-27 N) and South India (located at 7 N). The North India tea belt experiences hot, wet summer and cold, dry winter while the South Indian tea belt enjoys tropical climate (Hajra, 2019). The chief producers of tea crops in India include the Northeast Indian states of Assam and West Bengal and the South Indian states of Tamil Nadu and Kerala (Baruah and Handique, 2021; Mallik and Ghosh, 2022). Studies showed that rising temperature, increase in wind velocity, altered rainfall, and drought as consequences of climate change are detrimental for tea production in major tea producing regions of India (Baruah and Handique, 2021; Das et al., 2021). The previous study showed that monthly temperatures exceeding 26.6°C have reduced tea yields in Assam, India. Notably, an increase of just 1°C above an average monthly temperature of 28°C would result in a 3.8% decline in tea yield (Duncan et al., 2016). Climate changes have resulted in erratic rainfall and frequent droughts, severely impacting tea yields. Low tea productivity is attributed to erratic rainfall, particularly evident during the winter and pre-monsoon seasons of 2013, 2014, and 2021 (Sarma, 2022). Additionally, these changes have altered the tea pest landscape, with pests now causing greater damage due to increased reproduction, faster development, higher feeding rates, and more frequent secondary outbreaks (Pathak, 2004; Roy et al., 2020).

Sri Lanka and Kenya are the other two major tea-producing countries. In Sri Lanka, tea is grown as rain fed plantation crop which requires certain soil and air temperature as well as moisture condition for its growth (Bhagat et al., 2016). Tea plantation regions currently cover 16% of the Sri Lanka’s total agricultural land area including Central province (Kandy and Nuwara Eliya), Uva province (Badulla, Bandarawela, and Haputale), and Southern province (Ratnapura and Kegalle) (Jayasinghe and Kumar, 2023, 2019).The occurrence of extreme weather events such as droughts and high-intensity rainfall as a result of climate change has negatively impacted the yield and production of tea in these regions (Gunathilaka et al., 2017; Jayasinghe et al., 2021; Jayathilaka et al., 2012; Sujith and Hasula, 2017). These regions have faced prolonged dry spells and intensified monsoons, disrupting the balance of water availability crucial for tea cultivation. The drought events in the regions are mainly due to weak south-west monsoon in the Indian sub-continent leading to failure of wet season rainfall (Gunathilaka et al., 2017; Wijeratne, 1996). In Kenya, another major tea-producing country, tea is cultivated in high-altitude regions both east and west of the Great Rift Valley, where annual rainfall ranges from 1800 to 2500 mm (Ahmed et al., 2018, 2019). However, changes in seasonal rainfall patterns have caused both flooding and drought, which negatively impact tea quality and production (Kariuki et al., 2022; Muoki et al., 2020). Drought, in particular, is responsible for a 14－20% reduction in tea yield and 6－19% plant mortality (Ng’etich et al., 2001). In 2012, the Nandi Hills, a key tea-producing region in Kenya, experienced a severe frost event, leading to significant losses estimated at around 9.6 million USD. The area is also vulnerable to hail and frost, which continue to impact tea production (Kotikot et al., 2020). These climate shifts in key tea-producing countries highlight the vulnerability of tea cultivation to ongoing climatic changes and underscore the need for adaptive strategies.

Except for the occasional occurrence of cold damage, the main producing areas of tea trees in Korea are cultivated under meteorological conditions such as average annual temperature and average annual precipitation that are favorable for the growth of the species C. sinensis var. sinensis, which is mainly cultivated in Korea. The optimal areas for tea tree growth at present are Jeollanam-do, Gyeongsangnam-do, and Jeju-do in that order, and it can be seen that tea tree growth is higher in the southern region. As a result of predicting the possible areas for tea tree growth until the 2070s using the SSP245 and SSP585 scenarios, the growth probability of tea trees in the central and northern regions gradually increased, whereas in the case of Jeju-do, the growth probability varied greatly and tended to decrease, indicating the need to prepare for this by region (Kim et al., 2023).

Physiological and Biochemical Responses of Tea Plants to Climate Stressors

1. Temperature stress responses

Temperature is a crucial factor influencing the growth and productivity of tea plants. Tea plants can typically withstand temperatures ranging from 13°C to 26°C, with an optimal temperature for photosynthesis around 25°C to 30°C. When temperatures deviate from this range, especially during extreme heat or cold events, tea plants exhibit distinct physiological and biochemical responses (Table 2) (Arefin and Hossain, 2022; Barman et al., 2008). Heat stress, which occurs when temperatures rise above the optimal range, has profound effects on key physiological processes such as photosynthesis and respiration. The primary impact of heat stress on tea plants is the impairment of the photosynthetic apparatus, which leads to a decline in both photosynthesis and respiration rates. This reduction is largely attributed to decreased stomatal conductance in the leaves (Muoki et al., 2020). A recent study demonstrated that tea plants exposed to temperatures of 4°C and 35°C experienced environmental stress, which adversely affected photosynthesis process (Xia et al., 2022). Additionally, high temperatures can reduce chlorophyll content and impair the photosynthetic machinery, decreasing the plant’s ability to convert sunlight into chemical energy. This reduction in photosynthetic activity lowers growth rates and overall yield (Shen et al., 2019; Tan et al., 2023).

On the other hand, cold stress also has detrimental effects on tea plants. Exposure to temperatures below the normal range can negatively impact the photosynthetic capacity of tea plant leaves (Li et al., 2020; Oh and Koh, 2014). In response to cold stress, tea plants can inhibit enzyme activity and cellular damage, leading to reduced growth and productivity (Li et al., 2020). The combination of low-temperature-induced enzyme inhibition and impaired photosynthetic efficiency leads to a significant reduction in tea plant health and yield during colder periods. In Korea, the lowest average temperature recorded during winter from January to February 2011 was ‒5.6℃, 4.5℃ lower than the previous year. The cold stress had severe impacts on key tea-producing areas, particularly Hadong in Gyeongsangnam-do and Boseong-gun in Jeollanam-do, leading to 93.8% damage to tea plants in Hadong and 70.5% damage in Boseong (Hwang and Kim, 2012). As a result of the low temperatures, Jeju-do experienced a delayed first harvest and sustained 10% damage to its tea plants (Hwang and Kim, 2012; Lee, 2015). Furthermore, the cold shock altered metabolite levels, which negatively impacted the quality of the tea (Lee, 2015). Fig. 2 shows the impact of low temperature on tea plants in various regions of Korea including Jeollanam-do and Gyeongsangnam-do. The photographic evidence highlights the vulnerability of tea plants to late spring frosts, which can result in severe physiological stress. It shows varying degrees of damage, including leaf browning, wilting, and stunted growth, underscoring the need for effective management strategies to mitigate the impacts of climate variability.

Fig. 2

Frost damage in Korean tea fields. Photogrpahs showing the impact of low temperatures on tea plants across Jeollanam-do (A and B, taken in February 2023), Hadong (C, March 2013) and Jinju (D, March 2014) of Gyeongsangnam-do (E, February 2022) in Korea. The images capture the extent of frost damage, including leaf browning and wilting.

In response to both heat and cold stress, tea plants activate several biochemical pathways to mitigate the damaging effects of temperature fluctuations. One of the key responses to temperature stress is the activation of antioxidant pathways. Antioxidants like superoxide dismutase (SOD) and peroxidase (POD) help neutralize reactive oxygen species (ROS) generated under stress conditions (Li et al., 2020; Zhou et al., 2019). Additionally, tea plants produce secondary metabolites like catechins, which serve as natural defense compounds (Hao et al., 2018; Samynathan et al., 2021). The enhanced production of these metabolites not only helps the plant mitigate stress but also influences the quality of tea by affecting its flavor and health benefits (Shao et al., 2021). The enhanced production of these metabolites during temperature stress underscores their dual role in stress adaptation and tea quality enhancement.

2. Water stress responses

Water availability is another critical factor affecting tea plant growth, with both drought and waterlogging presenting significant challenges. Globally, the normal range of annual precipitation for tea cultivation is 1,500－2,000 mm (Arefin and Hossain, 2022). When precipitation petterns change, tea plants have evolved a range of physiological and biochemical mechanisms to adapt to water stress, whether caused by drought or waterlogging (Table 2) (Maritim et al., 2015).

Leaves, as key organs of photosynthesis, directly reflect plant responses to drought stress, with changes in their morphology closely linked to water deficit. Under drought, stomata close to reduce water loss, and leaf structure adapts by decreasing thickness and moisture content, helping retain water, reduce transpiration, and maintain photosynthesis (Chen et al., 2020; He et al., 2020; Maritim et al., 2015; Safaei Chaeikar et al., 2020; Waheed et al., 2012). The exposure of tea plants to drought has decreased polyphenol content and increased proline and total sugar concentration in Iranian tea clones (Safaei Chaeikar et al., 2020). Prolonged drought can lead to leaf shedding, reduced leaf size, and, ultimately, lower yields (Hajiboland, 2018; Waheed et al., 2012). Conversely, waterlogging due to excessive rainfall can suffocate roots by reducing oxygen availability in the soil, leading to root damage and reduced nutrient uptake (Nasrullah et al., 2022). Flooding stress is also known to significantly decrease the synthesis of quality constituents such as gallic acid and caffeine in tea plants (Jeyaramraja et al., 2003). Tea plants have developed several mechanisms to tolerate drought, including deep root systems that access water from deeper soil layers and physiological adaptations such as osmotic adjustment to retain cellular water (Damayanthi et al., 2011; Shen et al., 2022). They also exhibit water-use efficiency by optimizing water usage during periods of scarcity (Gupta et al., 2012; Pang et al., 2022). Understanding these responses is crucial for developing strategies to improve tea plant resilience to water stress, such as breeding drought-tolerant varieties and implementing efficient irrigation practices.

3. Responses to increased CO₂

Climate change is expected to elevate atmospheric CO₂ levels, which can have both positive and negative effects on tea plant growth and leaf composition (Table 2). At the same time, nutrient limitations, exacerbated by environmental changes, can further influence tea plant physiology. Elevated CO₂ levels generally stimulate photosynthesis and promote greater growth in tea plants due to increased carbon availability. This can lead to enhanced biomass production and potentially higher tea yields (Ahammed et al., 2020; Li et al., 2017). However, elevated CO₂ levels can also alter the composition of tea leaves, affecting the balance of primary and secondary metabolites (Li et al., 2017, 2018, 2019). For example, higher CO₂ concentrations may lead to an increase in carbohydrate content while reducing nitrogen-containing compounds such as amino acids and proteins (Ahammed et al., 2020). This shift in metabolite composition can impact tea quality, particularly in terms of flavor and nutritional value.

Nutrient stress, particularly deficiencies in essential elements such as nitrogen, phosphorus, and potassium, can have severe consequences for tea plant growth (Huang et al., 2022; Mudau et al., 2007). Under nutrient-limited conditions, tea plants may exhibit stunted growth, reduced leaf area, and lower chlorophyll content, all of which negatively impact photosynthetic efficiency (Mudau et al., 2005; Wang et al., 2013). Nutrient stress can also exacerbate the effects of other climate stressors, such as temperature and water stress, further reducing the plant’s ability to cope with environmental challenges.

Current Adaptive Strategies in Tea Cultivation

Climate change poses a significant threat to tea cultivation, with profound implications for the livelihoods of farmers. Shifts in climatic variables beyond the optimal range for tea production can severely affect both the quality and yield of tea. Therefore, it is essential to implement strategies aimed at mitigating the effect of climate change and its far-reaching impacts on tea production. The tea farmers are increasingly adopting adaptive strategies to safeguard their crops and ensure sustainable production (Ahmed et al., 2014b). These strategies focus on three primary areas: agricultural practices, breeding and genetic improvement, and pest and disease management (Fig. 3). By adjusting traditional farming techniques, developing climate-resilient cultivars, and employing integrated pest management (IPM) approaches, tea producers are better equipped to navigate the evolving environmental conditions (Ahmed, 2018; Ahmed et al., 2015). This section explores how these adaptive measures are being implemented to enhance the resilience of tea cultivation under climate change.

Fig. 3

Illustration of adaptive strategies in tea plant cultivation.

1. Agricultural practices

Investing in agricultural practices is a highly effective strategy for enhancing climate resilience in tea production systems. These practices, often referred to as Good Agricultural Practices (GAPs), play a crucial role in both mitigating the effects of climate change and adapting to its impacts. GAPs for climate mitigation and adaptation include agricultural diversification, tree planting and maintaining vegetative cover, management of soil organic matter and carbon sequestration, water management, and migration and relocating agroecosystems to more suitable locations (Ahmed, 2018; De Silva and Rathnayaka, 2014).

Farmers in southern Yunnan, China, report that agricultural diversification practices help reduce the vulnerability of tea plants to climate risks. These practices include integrating tea cultivation within agroforests, maintaining trees within tea plantations, and managing diverse forest buffers around tea farms (Ahmed, 2018; Ekanayake, 2003). Shade tree, intercropping, and mulching are being strategically integrated into tea plantations to mitigate the effects of climate change, such as excessive sunlight, rising temperatures, drought, and declining soil health. High temperatures and intense light caused by climate change can lead to photoinhibition in tea leaves within plantations. The use of shade trees in these areas helps mitigate photoinhibition and reduce local temperatures. This not only protects the tea plants but also enhances the development of functional components that contribute to tea quality (Mohotti and Lawlor, 2002; Yamashita et al., 2020). When tea plants are exposed to sunlight with air temperatures of 30－32°C, the temperature above the leaves can reach as high as 40°C. However, with the use of shade trees, the leaf temperature increases by only 1－2°C. The use of shade trees in tea plantations can prevent damage to tea plants caused by rising temperatures (Rokhmah et al., 2022). Intercropping is a key agroforestry practice known to enhance the microenvironment, as well as improve crop yield and quality. Such practices can also benefit the soil by minimizing erosion and enriching soil nutrients, leading to a more sustainable growing environment (Ekanayake, 2003; Wen et al., 2020). Soil mulching is a widely used agricultural technique globally. In tea cultivation regions like Assam, India, the adoption of soil mulching has significantly increased (Baruah and Handique, 2021; Rokhmah et al., 2022). During drought condition, soil mulching has been shown to effectively regulate soil microclimate, especially temperature and moisture, supporting the optimal growth of tea plants and enhancing the production of compounds that improve tea quality (Komariah et al., 2021; Nelum et al., 2023). In periods of increased precipitation, mulching helps reduce the impact of heavy rainfall by minimizing surface runoff and preventing soil erosion (Xianchen et al., 2020). The application of soil mulch in tea plantations in Qingdao, Shandong Province, China, led to a 12－13% increase in tea yield (Sun et al., 2011). Overall, the adoption of diverse agricultural practices, including shade trees, intercropping, and soil mulching, is essential for addressing the challenges of climate change in tea cultivation. These practices enhance both yield and quality while protecting the plants from the adverse effects of climate change.

2. Breeding and genetic improvement

Efforts in breeding climate-resilient tea varieties are gaining momentum to enhance plant tolerance to higher temperatures, drought, and other climatic stresses. These cultivars are essential for securing tea production in regions that are becoming increasingly vulnerable to climate change (Chen et al., 2012; Gunasekare, 2012; Jeong and Park, 2012). Breeding objectives for tea plants vary across geographic regions, depending on the specific climatic challenges faced in each area. In China, the world’s largest tea producer, cold tolerance is the primary focus due to the frequent occurrence of frost damage (Lou et al., 2013; Wang et al., 2021). In contrast, in India, particularly in Assam, breeding efforts prioritize waterlogging tolerance to address the heavy rainfall during the monsoon season (Parida et al., 2024). Globally, there are over 600 cultivated varieties of tea plants, many of which possess special traits such as tolerance to wind, drought, frost, waterlogging, and resistance to diseases and pests (Chen et al., 2007).

Early tea breeding focused on selecting plants from wild populations, an approach still valuable for improving traits like yield and quality. Many popular cultivars, such as ‘Longjing 43’, ‘Anhui 1’, and ‘Yabukita’, originated from these selections in China, Sri Lanka, and Japan. Controlled hybridization later became the preferred method for tea improvement, while techniques like polyploid and mutation breeding contributed to developing climate-resilient varieties (Al-Khayri et al., 2019). Traditional breeding remains a fundamental approach to developing resilient tea varieties. However, understanding the genetics behind how organisms adapt to changing climates is essential for developing more climate-resistant cultivars (Chen et al., 2007). Biotechnological advancements, such as gene editing and marker-assisted selection (MAS), have enhanced our understanding of the complex molecular regulatory networks involved in tea plants’ adaptation and tolerance to biotic and abiotic stresses (Muoki et al., 2020). These technologies are helping scientists develop tea plants that are not only more resistant to climate stresses but also to diseases and pests.

3. Pest and disease management

Tea plants are susceptible to a wide range of pests, including insects, mites, nematodes, and diseases (Mamun and Ahmed, 2011). Globally, 1034 species of pests are associated with tea, of which about 3% are common pests throughout the world (Ye et al., 2014). Approximately 808 and 380 species of insects and mites have been identified as pests of tea in China and India, respectively (Roy et al., 2020; Ye et al., 2014). These pests are responsible for an estimated 10－20% yield loss in major tea-producing countries such as China and India. Climate change is further altering pest and disease dynamics in tea cultivation across different regions. A notable change in weather patterns has been observed, including a reduction of approximately 200 mm in annual rainfall, a rise in average temperature by around 1.3°C, and an increase in CO₂ levels to 398 ppm. These climatic shifts have led to a change in the pest species associated with tea cultivation globally (Roy et al., 2020). In Chinese tea-growing regions, the sucking pest Empoasca vitis (smaller green leafhopper) causes annual yield losses of 15－20% and reduces tea quality. Seasonal outbreaks of E. onukii (tea green leafhopper) can result in up to 33% economic losses, significantly affecting summer and fall tea production. Additionally, Aleurocanthus spiniferus (orange spiny whitefly) is a major pest impacting tea plants in Northern China (Wei et al., 2015). In the Eastern Himalaya region of India, the sucking pests associated with major losses in tea production are Helopeltis, Empoasca, Scirtothrips, and Toxoptera (Sarkar and Kabir, 2016). The rise in temperature and changes in humidity also create favorable conditions for the spread of fungal diseases, such as blister blight (Exobasidium vexans) and root rot (Armillaria mellea) (Cherop, 2015; Otieno, 2002; Sen et al., 2020). These diseases thrive under warm and moist conditions, and with the altered rainfall patterns, tea plantations are increasingly at risk of fungal infections, which can lead to significant yield losses (Cherop, 2015; Otieno, 2002; Tompong and Kunasakdakul, 2014).

IPM approaches, which combine biological, cultural, and chemical controls, are being adapted to respond to the new patterns of pest infestations and disease outbreaks driven by climate change. Farmers are increasingly adopting biological control methods, such as using natural predators, parasites, or pathogens to manage pest populations. For example, the ant Crematogaster wrougtoni Forel is effective in consuming the eggs and larvae of Helopeltis, significantly reducing its abundance (Roy et al., 2015). In addition, application of fungal species including Trichoderma atroviride, T. asperellum, and T. harzianum effectively controlled pests and diseases of tea plantation (Kumhar et al., 2020). Adjusting farming practices, such as altering the timing of pruning or harvesting, can help disrupt pest life cycles and reduce infestations (Kawai, 1997; Mukhopadhyay et al., 2018). Additionally, using shade trees and intercropping in tea plantations not only helps regulate microclimatic conditions but also reduces pest pressure by creating a more complex ecosystem that can support natural pest enemies (Maleque et al., 2024; Pokharel et al., 2023). Although chemical pesticides are a component of IPM, their use is minimized and carefully targeted to reduce the risk of resistance and negative environmental impacts. In IPM systems, chemical controls are typically used as a last resort when biological and cultural methods are insufficient. Selective, environmentally friendly insecticides and fungicides are preferred to protect beneficial organisms and reduce harm to the surrounding ecosystem.

4. Innovations and Future Prospects for Climate Adaptation in Tea Cultivation

Great progress has been made in understanding the relationship between tea productivity and climate change. To better anticipate the impacts of climate change on tea cultivation and equip scientists with the necessary knowledge and tools, several innovative, multidisciplinary approaches are recommended for the future.

Quantifying Tea’s Long-Term Response to Climate Change

While significant progress has been made, key gaps remain in understanding how tea plants respond to long-term climate stresses. Research on the cumulative impact of rising temperatures, fluctuating precipitation patterns, and increased CO₂ levels on tea quality, yield, and resilience is still lacking. Filling these knowledge gaps is crucial for developing comprehensive adaptation strategies. Future research should focus on measuring how tea plants respond to increased CO₂levels over the long term. This will help understand the link between carbon supply and plant growth. Technologies like Free Air CO₂ Enrichment (FACE) can be used to examine the impact of elevated CO₂ on tea yield and quality at the ecosystem level (Rwigema, 2021).

1. Enhancing tolerance to combined stress conditions

Future research should focus on optimizing breeding techniques for developing tea varieties with enhanced resistance to both biotic and abiotic stresses (Muoki et al., 2020). Research programs should prioritize developing tea plants that are tolerant to a combination of stress factors, such as drought, heat, and pests, that more accurately mimic real field environments (Chen et al., 2007). A focus on the limitations of tea plants’ morphological, biochemical, and molecular adaptations to stress will guide the development of improved, climate-resilient varieties. Additionally, investigations into sustainable pest management practices, improved soil health under climate stress, and the socio-economic impact of climate adaptation on tea farming communities will be critical for shaping effective climate resilience strategies.

Conclusion

The review has highlighted the growing importance of adaptive agricultural practices in safeguarding tea cultivation from the adverse effects of climate change. By adjusting planting schedules, improving soil and water management, and developing climate-resilient cultivars, tea farmers are already making strides in adaptation. Sustained research and innovation in tea breeding, and pest management will be essential to mitigate the effects of climate change on tea cultivation.

The review has highlighted the various ways in which climate change is affecting tea cultivation, from direct impacts like heat stress and drought to indirect effects such as increased pest infestations. Current adaptive strategies, including adjustments in agricultural practices, breeding climate-resilient cultivars, and implementing pest management techniques, are already helping tea farmers adapt. However, sustained research and innovation in tea breeding, pest management, and climate monitoring technologies will be critical to ensuring the long-term sustainability of tea production.