Abstract:
This study aimed at statistical analysis of the recent trend of climate change and prediction of future climate change scenarios with Global Climate Models (GCMs) and most importantly investigation on the impacts of climate change on rice production. The Satkhira district was taken as the study area, which represented the coastal zone of Bangladesh. There was a statistically non-significant increasing trend of annual maximum and minimum temperature and annual total rainfall through the period of 1950-2006. The trend analysis of seasonal rainfall for the period 1981-2006 could reveal that, from the last two decades the seasonal normal rainfall pattern has been altered. Rainfall in pre-monsoon and winter season had a decreasing trend whereas it had an increasing trend during monsoon and post-monsoon seasons. Temperature variations had an observable effect on crop yield. The summer crop Aus production was decreasing significantly. The production of Boro rice, a winter crop is increasing significantly with the increase of lowest minimum temperature. The inter-annual variation in the amount of winter season rainfall was little. Boro production, therefore, was insignificantly affected by this variable. However, correlation between the production and climatic variables was not statistically significant. In case of the future climate change prediction, GFDL-TR predicted delta values ranging from 1.1 to 1.7°C for 2050, while it varied from 1.5 to 2.3°C for 2070. Whereas, UKTR suggested mean temperature increase was 1.5 to 2.1°C in 2050 and 1.2 to 2.7°C in 2070. According to HadCM2 generated delta values, temperature would increase 1.3 to 2.9°C in 2050 and 1.7 to 4.0°C in 2070. It could be seen that different GCMs predicted different sets of values for rainfall increase (or decrease). Among the three GCMs, GFDL-TR predicted milder changes while HadCM2 suggested severe changes and the values increased with time. In case of rainfall, GFDL-TR and UKTR both predicted a decreasing tendency in future during winter season (DJF). However, HadCM2 suggested that there would be higher precipitation (35.6% increase in 2050 and 48.9% increase in 2070) during the winter season (DJF), which will be beneficial for agriculture. Different crop responded differently under different climate change scenarios. Yield of Boro was reduced from 3.47 to 48.64% in calcareous soils, while, it was increased from 0.16 to 16.47% in noncalcareous soil conditions. In case of T. Aman, mainly increased yields (up to 49%) could be observed under rainfed conditions in future climate change scenarios. However, there was also declining trend of yields ranging from 1 to 12%. The most detrimental effects were observed in case of T. Aus. The yield decreased in all soil conditions and future climate scenarios. The per cent yield difference decreased from at least 5% up to 42%. In most cases, irrespective of crops and GCMs, climate change would have negative impact. Therefore, in the event of climate change the cropping pattern of the region may change considerably. Agriculture in Bangladesh is already under pressure both from increasing demands for food, and from problems of agricultural land and water resources depletion. The prospect of global climate change makes the issue particularly urgent.
Page(s):
37-50
DOI:
DOI not available
Published:
Journal: Pakistan Journal of Meterology, Volume: 6, Issue: 11, Year: 2009