Climate Change and Extreme Events in WL1a Agro-ecological Zone of Sri Lanka: Implications on Coconut Production

The temporal variations in rainfall, temperature and the associated extreme events were examined with the objective to ascertain their potential effects on coconut production in Ratnapura district of Sri Lanka. Temporal variations were measured using Mann-Kendal test and extreme events were examined using climate indices related to daily rainfall and daily temperature. Daily rainfall and minimum and maximum temperature data of Ratnapura representing Agro Ecological Region, WL1a obtained from the Department of Meteorology of Sri Lanka for the period of 1961 to 2015, were used for the analysis. The base period was considered as 1961 to 1990 as recommended by the World Meteorological Organization. According to the results of the Mann-Kendall tests, minimum temperature had a positive trend and maximum temperature had a negative trend. Among sector-specific climate indices, Standardized Precipitation Evapotranspiration Index in the long-time scale and minimum temperature showed a significant positive trend and the value of the 95th percentile of maximum temperature showed a significant negative trend. The other indices related to drought, extreme rainfall, extreme warm days and maximum annual number of consecutive dry days did not show significant trends during the period 1991 to 2015. Despite the latter, the former indicates an occurrence of drought like situations in the future. Adoption of both short and long-term drought control measures in coconut cultivations if they are to be promoted in Agro Ecological Region of WL1a are recommended as prolonged droughts and high temperatures adversely affect production of coconuts.