Stir Tea Coffee Industry Bi-Monthly

Climate Change and Tea Production



Climate change in India
Harki Sidhu, consulting program coordinator India, Rainforest Alliance, reports a long list of major problems throughout India:
“Over the past decades the industry has been witnessing some dramatic changes… yields are dropping, pests and diseases are increasing and becoming more resistant, response to applied fertilizer is reducing, organic matter and microbial population in soils is reducing, weed flora is changing and becoming more resistant, water-tables are rising due to monsoons and rain falling during the dry season, weather conditions are becoming extreme and erratic.”
In northern India, Darjeeling tea growers agree that they are currently experiencing difficult conditions.
“The weather is becoming very extreme and intense with much longer dry periods, or heavy downpours over many days and frequent hail and cyclonic storms,” Ashok Kumar of Goomtee Tea Estate explained. “The bushes are stressed, pest populations are increasing and monthly crop cycles are changing unpredictably.”
 “During the past 100 years, since meteorological data has been recorded, temperatures in Assam and Darjeeling have gone up by 2 degrees and rainfall has become erratic,” said Sudhir Prakash of Glenburn Estate and ex-chairman of Jorhat Tea Research Association. “Climate that is conducive to tea growth is one in which there is sunlight during the day and rain at night on an almost daily basis. Although the quantum of rain has not changed much, the frequency had reduced and the rise in temperature has adversely affected photosynthesis in the plants. These climatic changes have resulted in lower crops as well as a higher incidence of pests and diseases and yields are showing a downward and erratic trend.”
In Assam, Kaushik Saikia, of Williamson Magor Group, explained that the rise in temperature, uneven distribution of rainfall, flash floods, and prolonged drought conditions have led to massive soil erosion (which at times results in the loss of productive areas), severe loss of crop, and damage to young tea.
“Prolonged surface water-logging has caused higher incidents of plant diseases and decreased production,” he said. “Long periods of rainfall and fewer hours of sunshine have led to a higher incidence of pests and diseases and to crop loss due to a reduction in photosynthesis rate; changes in rainfall patterns have had a negative impact on fertilizer application, pest management, planting and young plant management, weed management, etc; intense and destructive storms and hailstorms have damaged plants, and significant changes in the natural equilibrium have triggered an imbalance in the prey-predator relationship in the region, thus increasing the number of pests and diseases. It has been reported that climate changes have also resulted in a shift in the quality of the Assam brew in terms of flavor.”
In southern India, an even more severe picture is emerging.
“Rainfall has dropped by 30% on a 10 year average and distribution and timing are erratic and do not follow the normal patterns of, typically, pre-monsoon showers in April/May, the south west monsoon in June/July/August and the north east monsoon in mid September through to mid November,” according to Dharmaraj Naren of Harrisons Malayalam Ltd. “Crops are adversely affected with a 10% drop in yields because of prolonged dry periods. This inconsistent pattern is causing sudden pest attacks, rendering pest surveillance and control extremely tough. Even established old tea bushes in the drought-prone areas are dying and conditions pose a big challenge for replanting, a key intervention to boost the productivity of old tea.”
In their 2011 report, Impact of Climate Change on Southern Indian Tea Plantations, P Mohan Kumar and R Raj Kumar wrote, “Among the factors that influence the crop productivity, climatic variables are independent in their nature. Each variable either alone or in combination imposed stress to the plants; the compounded effect of change in climate not only affects the plant metabolism but also influenced the crop productivity. Gradual change in climatic change will not impose any deleterious impact on crop productivity. But sudden change in climatic variable may impart stress on the plants and sudden break out of pest and pathogens.”
A further study on Changing Pattern of south west monsoon in the Animallais (part of the southern Indian tea growing region) by R Raj Kumar, E Edwin Raj and P Mohan Kumar says, “Increase in the atmospheric temperature, change in rainfall pattern and its erratic distribution may affect the productivity under south Indian conditions to a greater extent. … Looking back at the records, the Anamallais may experience inadequate showers in the months to come and its compounded effect with other ecological factors may cause severe drought.”

Sri Lanka’s climate problems
 “Flooding and droughts have been occurring in quick succession in different regions in recent years and available data and visual observations suggest a pattern of extremes, in both rainfall and dry periods,” said Anura Gunasekera, senior manager for special projects at Dilmah Tea. “Studies carried out in respect of the period 1961- 2002 indicates that the number of wet days has decreased in all sub-stations, except in Nuwara Eliya. Similarly, watersheds in the north of the country appear to have increased in volume with a decline in the watersheds in the south. Nationally, there is an apparent reduction in rainfall with dry/wet periods being more intense.”
Sarath Sirisena, managing director/c.e.o. of Lanka Commodity Brokers Ltd. (LCBL), adds that “temperatures have risen in some tea growing areas over the past 50 years – in Nuwara Eliya by 1.02° C, in Uva- Badulla by 0.38° C, and in Ratnapura 1.16° C. Predictions for 2100 are for further increases of 1.4-2.7° C. The optimum temperature for the highest yields is 22° C and the loss of crop per degree above that per month per hectare is estimated at 10 kg. Regions that experience temperatures below that optimum will gain 15 kg per hectare per month for each degree rise up to the optimum. This means that high grown output will increase and low grown output will decrease in the short term.”
Also predicted for the region are high variability in rainfall, increased soil erosion, a dramatic rise in the incidence of pests and diseases and of course impacts on productivity and quality.
The low-growing region of Sri Lanka has been experiencing floods and heavy rainfall in areas where such phenomena are rare or unprecedented. Malinga Herman Gunaratne? of Handunagoda Tea Estate in Ruhuna district explains that: “there have also been unusual cyclonic conditions which have destroyed many houses, not only in the coastal areas but also inland on the plantation belt and many lives have been lost. The biggest problem has been earthslips and general geological movement. In the Matale District, many settlements had to be evacuated and the people relocated due to recurrent earth movement. At the same time, in some plantation districts, the monsoon rains have failed or have been very weak and this has adversely affected tea crops.”
The impact on tea and on agricultural programs in Sri Lanka, as elsewhere, is complex and intense. As Gunasekera details, “Excessive and intense rainfall increases soil erosion, provides conditions conducive to fungal diseases that are harmful to the green leaf, washes away nutrients before the plant is able to absorb them and overall, inhibits crop and the quality of the black tea, particularly in the high grown areas above 4000 feet. Very dry weather increases both ambient and soil temperatures and has a big impact on tea in the mid-grown and low-grown sectors, resulting in high bush fatalities, large vacant patches in tea fields, and reduced productivity. And, unless the soil condition of vacant areas is satisfactory, resupplying with new tea is not a viable option and such areas must be planted with grass, or some other cover crop, to prevent further soil degradation or erosion. Evaporation of moisture from the ground is accelerated, again impacting on bush health and bush productivity and resulting in crop decline.”
And, as in other countries around the globe, higher temperatures at higher altitudes encourage pests and diseases which impact bush productivity and programs aimed at combating this inevitably increases costs.
“Infestations of shot-hole borer and live-wood termite, pest infestations which have an intensely damaging impact on the bush frame and consequently on bush longevity and productivity, were confined to lower elevations,” Gunasekera commented. “According to most working plantation managers and plantation agricultural advisers, such pests are now becoming increasingly common at higher elevations.”

The changing African climate
Africa too is experiencing similar shifts in expected patterns. Fred Ssegujja, chief factory manager, McLeod Russel Uganda Ltd., sent news that “longer and more severe drought conditions are being experienced from time to time and uneven rainfall has become more common in the last seven years, with lower rainfall being recorded. Bushes are not recovering vigorously after dry spells and a number of bushes do not recover at all, thus leading to loss in yields. The change in weather patterns has led to encroachment on wetlands and natural forests, and water scarcities have become rampant. We’ve also seen drought-resistant weeds becoming more predominant, and roads have on some occasions been washed away by rains, rendering the transportation of green leaf impossible.”
From Malawi, Albert Changaya, director of the Tea Research Foundation of Central Africa in Mulanje, reports that: “over the past 50 years, temperatures have risen by 0.44° to 0.83° C in Thyolo and Mulanje areas, while rainfall is now averaging 1,000 – 1,200mm – down from around 2,000 mm per year. In addition, the distribution of the rains has changed so much. While the tea growing area used to have a minimum of 50mm each month for the whole year, we now have four or five months of total dryness. Bush mortality is high – I estimate about 2% – and there has been an increase in the occurrences of pests and diseases in the fields due to increased temperatures. Low tea production means that earnings, both local and foreign, have been negatively affected and the labor force has to some extent been negatively affected because of low production of tea.”
 “In the last two years, we have had dry warm winters, whereas the tea areas traditionally had cool wet winters with only two ‘dry’ months of the year,” Alexander Cathcart Kay of Satemwa Tea Estate, Malawi, added. “In the 2011/12 season, we actually got 40% of our annual rain in a single month, and of that, 50% fell in one weekend. I’ve also noticed that there has been less cloud cover during the summer rainfall months and the type of rain has changed – more short, heavy rainfall than prolonged periods of rain. This means that the dry period during the rainy season can affect the crop more as the moisture table is not good. The prolonged dry period is negatively affecting yields and bush vitality and this of course feeds into cashflow, levels of employees the business can sustain, etc.”
In Kenya and other East African regions, The Ethical Tea Partnership has for several years been involved in research with tea boards and tea companies to monitor the challenges caused by changes in climatic conditions. They report that: “already Kenya is witnessing increasing temperatures, decreasing rainfall and increases in the propensity of hail, droughts and frosts. Tea is a crop that is particularly dependent on well-distributed rainfall and thus such changes pose a threat to tea supply chains globally.”
The Tea Research Foundation Kenya (TRFK) has been monitoring Kenyan climatic data for many years and over the past 52 years, has seen annual temperature rises, decreases in annual rainfall of 4.82mm per year (totaling 250mm over the period), and a larger soil water deficit, especially in January, February and March, resulting in significant reductions in tea productivity. Over the next 15 years, the major issues are expected to include water scarcity due to long term rainfall decrease, soil erosion and landslides, harvest losses, a decline in soil fertility, an increase in and a reduced resistance to pests and diseases, a drop in tea quality, poverty and food shortages.

China, Taiwan, Vietnam, and Japan
Of both China and Taiwan, Leo Kwan of Tea Hong says: “climate patterns have been irregular and very different from in recent years. In the south east, where a monsoon-type climate dominates, typhoons and extreme fluctuations in temperature and humidity are causing a major threat. In the south west basins and continental mountains, drought, sudden rainstorms – with landslides that follow – and heat have caused bankruptcy for many farm owners, especially early last year in Yunnan. Unusual weather also breeds pests. For example, Macrophoma theicola, a fungal infection that attacks bushes during very dry and hot conditions, has become a regular issue that Taiwan growers are trying to deal with. The loss in harvest has been so frequent, both on the mainland and in Taiwan, that farmers are already having to build it into their costings and that of course affects prices and sales. On the mainland, if a loss on a farm is evidently recoverable, the banks are willing to lend money and fluctuations in price have been quite smoothly absorbed. But farmers in Taiwan are not so lucky.” Thomas Shu of ABC Tea adds, “By the end of November last year, Taiwan had been suffering from a long drought for the previous 3 months, and in the early months of winter 2012 the farmers were ‘crying’ because of the very unusual drought that followed the Typhoon season. We took our 2012 TOST group (Taiwan Oolong Study Tour) to Alishan in October to learn how to make oolong tea and the farmer we contracted could not harvest enough tea from his own garden – only 24 kg of fresh leaf – and so the leaves (simply regular leaves for making jade oolong) cost as high a price as Oriental Beauty. Mother Nature is still a key factor!”
In Japan, the last five years have brought very hot summers, sometimes with very heavy rain or drought, and cold winters.
“Strong typhoons with heavy rain and strong winds hit the tea fields and cause floods and soil erosion. Drought from mid-summer to autumn and very high temperatures will cause a decrease in yield during the first harvest in 2013,” Mari Kawashimo of the World Green Tea Association in Japan said. “This is because the tea buds are not dormant during the winter due to the warmer air and are therefore more tender and more easily damaged by frost in late autumn and early spring. And there has also been an increase in diseases and insect damage.”
Kei Shimizu, who grows tea in Sayama, north of Tokyo, agrees.
“We have been experiencing long, very hot summers with higher temperatures than usual – last year there were a record 57 ‘summer days’ when temperatures were above 30 C. In 2012, we had a very short autumn and cold winters with temperatures below zero every morning,” Shimzu said. “Late frosts are a problem and early tea shoots are easily damaged so we’ve started planting varietals that grow more slowly. Climate change also means we now find harmful insects in the north of the country which in the past only lived in the south.”
Vietnam has also seen a significant rise of approximately 2° C in temperatures in 2011/2012, compared to average temperatures recorded for 2006-2010. And as elsewhere, rainfall has been erratic with drastic variations in distribution and rainfall patterns. Rainfall recorded in the past 30 years shows an average of 1,500mm but the total for 2012 was at an all-time low of 884mm followed by 2,003mm in 2011. And the uneven distribution of rainfall has resulted in a greater frequency of drought in some plots, since Vietnam is solely dependent on rainfall and irrigation facilities cannot be put into effect due to the elevation and the undulating terrain. The country has also experienced water logging in low-lying areas, damage by lightning to shade trees during the rainy season, and the unpredictable rainfall has had an impact on such practices as fertilizer application, pest management, young tea management, weed management, etc. Variations in weather and rainfall distribution during monsoons have also led to higher incidents of pests and diseases, and a wider use of pesticides and chemicals has had serious consequences on the marketing of Vietnamese teas in the West.
In a second article, we will discuss how tea farmers, tea blenders and packers, scientists, tea research stations, and ethical bodies such as Rainforest Alliance, Ethical Tea Partnership and Fairtrade International, are working around the world to try and manage the effects of climate change.