Association between Empirically Estimated Monsoon Dynamics and Other Weather Factors and Historical Tea Yields in China: Results from a Yield Response Model

Abstract

Farmers in China's tea-growing regions report that monsoon dynamics and other weather factors are changing and that this is affecting tea harvest decisions. To assess the effect of climate change on tea production in China, this study uses historical weather and production data from 1980 to 2011 to construct a yield response model that estimates the partial effect of weather factors on tea yields in China, with a specific focus on East Asian Monsoon dynamics. Tea (Camellia sinensis (L.) Kunze) has not been studied using these methods even though it is an important crop for human nutrition and the economic well-being of rural communities in many countries. Previous studies have approximated the monsoon period using historical average onset and retreat dates, which we believe limits our understanding of how changing monsoon patterns affect crop productivity. In our analysis, we instead estimate the monsoon season across China's tea growing regions empirically by identifying the unknown breakpoints in the year-by-province cumulative precipitation. We find that a 1% increase in the monsoon retreat date is associated with 0.481%-0.535% reduction in tea yield. In the previous year, we also find that a 1% increase in the date of the monsoon retreat is associated with a 0.604% decrease in tea yields. For precipitation, we find that a 1% increase in average daily precipitation occurring during the monsoon period is associated with a 0.184%-0.262% reduction in tea yields. In addition, our models show that 1% increase in the average daily monsoon precipitation from the previous growing season is associated with 0.258%-0.327% decline in yields. We also find that a 1% decrease in solar radiation in the previous growing season is associated with 0.554%-0.864% decrease in tea yields. These findings suggest the need for adaptive management and harvesting strategies given climate change projections and the known negative association between excess rainfall and delayed monsoon retreat on tea quality and yield.

Kenyan tea is made with heat and water: how will climate change influence its yield?

“…Factors such as frost, hailstorms, and pests, are not included, though losses incurred by such events can be substantial for tea [2]. The timing of climatic events, such as the onset and retreat dates of the seasonal rains, may also play a role in historical and future tea production [32] and should be investigated in future studies.…”

Global Warming and Tea Production—The Bibliometric View on a Newly Emerging Research Topic

“…Due to the few papers and the multitude of regions and methods applied, there are hardly any conflicting results. From the perspective of the cited references, there are four papers standing out with 10 or more citations until present [5,27,30,31].…”

“…The publications by Wijeratne [5,13] discuss the impact of climate change on tea production in Sri Lanka, whereas the papers by Ahmed [9,10,27] focus on the impact of climate change on tea quality in general. The other key papers deal with the impact of global warming on the tea production in South China [12,[28][29][30], Northeast India [6,7], Sri Lanka [14], and Eastern and South Africa [31][32][33]. Some additional and highly relevant publications have been identified by considering the citing papers and by reference analysis via RPYS (see below).…”

“…The paper by Boehm et al [30] deals with the association between monsoon dynamics and historical tea yields in China. The study uses historical weather and tea production data from 1980 to 2011.…”

The impact of climate change on labour demand in the plantation sector: the case of tea production in Sri Lanka

“…Consequent impacts of climate change on employment opportunities are likely to be a major concern to governments of developing nations because plantation sectors provide regular employment for a significant percentage of the agricultural workforce in countries such as Sri Lanka, Kenya, Vietnam and Bangladesh (Wijeratne ; Boehm et al . ).…”