Which way the weather will shift nobody knows, this is what tea planters are worried year by year.
Unusual weather patterns were noticed in July in tea estates in Upper Assam. Rainfall recorded was only 163.30mm against 484.00mm in July last year. Rainfall was mostly in day time unlike 2019, where the rainfall was mostly in the night time.
Regarding Relative Humidity ( RH), during June & July a reverse trend was noticed between 2021 and 2019 for both morning and afternoon hours. In July 2021, right from the beginning, the RH was much below as compared to 2019 particularly in the afternoon hours.
Climate change has impacted the timing of the seasonal rainfall all over the world but in Assam, it could affect the livelihood of millions. The State Action Plan of Assam, clearly indicated an increase in average temperature and changed the timing of the seasonal rainfalls along with a prediction of lesser rainfall in the future all over Assam. Unfortunately, a shift in the season rainfall could lead to a shorter growing season for tea, which especially lowers yields of the first
flush and the second flush( the earliest and most valuable harvests). A study by FAO, 2014 showed that the annual total precipitation is likely to decrease in almost all over Assam except in some areas in the Cachar region .
TEA YIELDS TO DECLINE
Modelling results indicate that tea yields in north-east India are expected to decline by up to 40 per cent by 2050 due to climate change. Studies have confirmed a decreasing tea yield in response to warmer monthly average temperatures whereas precipitation variability, and in particular intensity, negatively affects tea yield. In fact there were near-drought conditions in Assam forcing closure of tea factories. Planters said this is for the first time that factories had to be closed in May hitting production.
And to make it much worse, the Intergovernmental Panel on Climate Change( IPCC) in its 2021 Climate Change Report has already warned on what is to come- “Global surface temperature will continue to increase until at least the mid-century under all emissions scenarios considered. Global warming of 1.5°C and 2°C will be exceeded during the 21st century unless deep reductions in carbon dioxide (CO2) and other greenhouse gas emissions occur in the coming decades”.
For South Asia, heatwaves and humid heat stress will be more intense and frequent during the 21st century, the IPCC says.
ADAPTIVE MEASURES UNDERWAY
A number of research studies have said climate change will affect tea cultivation and there is research and dialogue going on about what are the adaptive measures which need to be implemented. The positive news is that garden managers in Assam are using adaptive measures that growers will find useful in many tea lands. These include rainwater harvesting to enable irrigation during dry spells, reforestation, conservation of biodiversity, soil mulching, and the creation of wind barriers that combine to mitigate the threat. A study Perception of Climate Change and Adaptation Strategies in Tea Plantations of Assam India has analyzed tea growers’ awareness of climate change, its impact on tea, adaptive approaches undertaken and future strategies. The study was recently published in Environmental Monitoring and Assessment journal and the work was authored by Dr. Pradip Baruah and Dr. Gautam Handique at Tocklai.
The scientists note that climate change is a global concern with impacts that vary at the farm level. The majority of respondents were aware of changing climate conditions and the effect on tea production. How farmers respond to climate change needs to be precisely understood if the government, policymakers and researchers are to effectively support adaptive and mitigative approaches for the tea crop. The impact of higher temperatures, erratic and often torrential rains are evident, according to Dr. Baruah. “As future management strategies, tea growers have opted to gradually replace synthetic fertilisers with organic manures and pesticides, construct anti-erosion measures along riversides and embankments, generate awareness programs among the workers and other residents on
conserving biodiversity, generate clean energy for tea production and cultivate climate tolerant/resistant cultivars” the study observed.
The Trinitea program is currently working with more than 45000 tea smallholders and have brought more than 27000 hectare of the land under climate smart practices all over Assam. A team of tea experts have conducted several training sessions to increase the awareness of climate smart practices and how the adoption of these practices reduces the impacts of climate change on tea yield. The biggest contributor to the problem of climate change is increased GHG emissions. Practices like efficient use of N fertilizer (largest carbon footprint), reduced burning of trash and crop residue directly reduces the carbon footprint of the tea. . Several soil moisture conservation practices including green manuring, mulching and cover cropping are promoted to mitigate the impact of warmer temperature on the soil resulting in a sustained yield. The conditions were so bad that Tocklai had to issue a special bulletin on management of adverse stress conditions due to drought-like situations.
“The new season of 2021 has been a difficult year for the tea industry of Assam so far due to high deficit of rainfall both in quantity and number of rainy days. The average maximum temperature is also comparatively higher. The crop harvest of the tea estates across Assam has been badly affected due to the prevailing moisture stress conditions resulting in longer banjhi period, stunted growth, wilting, defoliation and die back of branches in varying degrees which has even led to withdrawal of plucking temporarily in some tea estates” it says.
All over the world, perennial crops like tea are also considered to be a sink for atmospheric carbon (CO2). The shade trees planted with tea bushes capture and store the atmospheric C02 in their tissues. According to a recent study by Kalita et al., 2016 the tea plantations lock down close to 6000 kg per hectare per year of carbon in their biomass. There are many initiatives under carbon finances where these stored CO2 can be sold in market as carbon credits upto Rs 1800 per tonnes of CO2 per hectare per year.