Remote Impacts from El Niño and La Niña on Climate Variables and Major Crops Production in Coastal Bangladesh

Abstract

El Niño and La Niña Southern Oscillation (ENSO) are major drivers that affect climatic variables in many countries. Therefore, ENSO mediated variation in climatic factors have significant consequences for crop production. We studied ENSO mediated variations in temperature and rainfall in the five coastal districts of Bangladesh during 1951–2017, and the impacts on major crops production were analyzed using growing degree day (GDD) index. Statistical analyses were performed on different climatic parameters in relation to ENSO events and locations. Results indicate that ENSO events had significant influence on monthly, seasonal and annual temperature and rainfall amounts (p < 0.05). Specifically, maximum temperature under ENSO phases were higher during Kharif-I and Kharif-II seasons than neutral years. In contrast, the minimum temperature was higher in neutral years than ENSO events during Rabi season. Averaged across stations, annual mean maximum temperature was 0.5 and 0.23 °C higher during El Niño and La Niña compared to neutral years. Rainfall was higher during neutral years compared to El Niño and La Niña. These changes in seasonal temperature variably changed crop GDD in different locations and thus, crop growth duration and crop yield. Therefore, this study provides a general understanding to ENSO mediated impacts on coastal agriculture in Bangladesh.

Keywords

• El Niño and La Niña southern oscillation
• temperature
• growing degree day
• rainfall
• crop production