Abstract

The extreme climatic events are increasing because of climate change impacts and thus likely to influence global agricultural production. Regional assessments on various abiotic factors and its influences on biological entities in diverse geographic locations are needed for understanding uncertainties. Rice grain yields and daily temperature data from 1971–2015 were used to quantify extreme temperature events in different regions of Bangladesh and their impacts on rice yields growing in three seasons of Bangladesh. The regional averaged trends in temperature extremes were consistent with global warming. The occurrence summer days (SU), tropical nights (TR), warm days (TX₉₀), and nights (TN₉₀) and a warm spell duration indicator (WSDI) increased by 0.388 (P_0.00001), 0.103 (P_0.19), 0.520 (P_0.00000), 0.269 (P_0.0004), 0.147 (P_0.0001), days yr^-1, respectively. The frequencies of cold days (TX₁₀) and nights (TN₁₀), and cold spell duration indicator (CSDI) showed decreasing trends of −0.143 (P_0.0006), −0.254 (P_0.001), and −0.04 (P_0.227) day yr^-1, respectively. Sharp increases of TR and TN₉₀ indices took place in 1985–2000. Principal component analysis showed that SU, TX₉₀, TN_90, WSDI, TX_10, TN₁₀ and diurnal temperature range (DTR) were the main influencing factors for seasonal variations in rice yield. Warm and cold nights played a vital role in reducing rice yields. It can be concluded that extreme temperature events will be increased in Bangladesh and thus necessitating heat and cold tolerant rice varieties with appropriate management options for sustained future rice production in Bangladesh.

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