[NEW DELHI] Rice yields across Bangladesh could decrease by almost half over the next six decades because of global warming, scientists report.
The Bangladesh University of Engineering and Technology (BUET) and the South Asian Association of Regional Cooperation (SAARC) Meteorological Research Centre used a computer model to simulate the yields of two popular rice varieties in 2008, 2030, 2050 and 2070 across 12 locations in major rice-growing areas of the country.
They used the 'CERES-Rice' model — a computer model that evaluates the effect of land use and environmental changes on rice production — to incorporate data such as the genetic characteristics of the two varieties; soil, water and weather data; and crop management practices such as planting date and fertiliser application.
The model predicted a decline in yields of more than 20 per cent by 2050 and 50 per cent by 2070, for both varieties, Mohammad Nazrul Islam — a professor at BUET's Institute for Water and Flood Management (IWFM) — and colleagues reported at a seminar on climate change and development needs, held in Dhaka earlier this year (21 April).
An increase in daily temperatures and shifts in rainfall patterns will be the major causes of this decline, the scientists say.
A related study by A. K. M. Saiful Islam — also at the IWFM — published in Open Atmospheric Science Journal earlier this year (March), shows that mean temperatures in Bangladesh have risen by about one degree Celsius over the last half-century.
Using a regional climate modelling system developed at the United Kingdom-based Hadley Centre for Climate Prediction and Research, the researchers assessed temperature changes in Bangladesh from 1948–2000 as well as future predictions for temperature and rainfall until 2090.
The analysis reveals that temperatures are expected to rise, on average, by 1.7 degrees Celsius by 2050 and 3.3 degrees Celsius by 2090 — relative to average temperatures of 25.4 degrees Celsius in 2000, Saiful Islam, associate professor at BUET's Institute for Water and Flood Management, told SciDev.Net.
Rainfall is also projected to increase relative to 2000 values by about four millimetres per day until 2050, and about two millimetres per day until 2090.
Saiful Islam told SciDev.Net their findings will be applied to wide-ranging studies, such as the impact of the changes on livelihoods; drought and flood forecasting; and disaster management.