Vulnerability of Sri Lanka tea production to global climate change

The tea industry is Sri Lanka's main net foreign exchange earner and source of income for the majority of laborers. Tea yield is greatly influenced by weather, and especially by droughts, which cause irreparable losses because irrigation is seldom used on tea plantations. At the other extreme, heavy rains erode top soil and wash away fertilizers and other chemicals. In the recently published Sri Lanka country report on climate change, it was reported that the island will experience extreme rainfall intensities and warmer temperatures as a result of climate change. The possibility of a 10% increase in the length of dry and wet seasons per year in the main plantation area was also indicated. Thus both drought damages and soil losses in tea production areas will increase in the years to come. An analysis of the results of field experiments with weather data shows that increases in temperature, soil moisture deficit, and saturation vapor pressure deficit in the low elevations will adversely affect growth and yield of tea. Reports have also shown that about 30 cm of soil has already been eroded from upland tea plantations. Under these circumstances, the tea industry in Sri Lanka is clearly vulnerable to predicted climate changes, and subsequently greater economic, social, and environmental problems. This paper discusses the various aspects of the adverse effects of climate change on Sri Lanka's tea industry.