Integrating climate impacts on agriculture to prioritize policy – local effects, external floods, and isolated uncertainty in Bangladesh

We present results from a comprehensive study of climate impacts on the agricultural sector in Bangladesh, integrating multiple climate stressors (carbon dioxide, temperature, precipitation, river floods, and sea level rise) to identify vulnerabilities and prioritize regional adaptation strategies. Analysis was conducted by passing climate scenarios from 16 global climate models and 2 emissions scenarios through a biophysical crop model in each of 16 Bangladeshi sub-regions, with results combined with output from a hydrologic model of the Ganges-Brahmaputra-Meghna Basin and a coastal model of the Bay of Bengal. To identify the relative vulnerabilities from each climate stressor, experiments examined three seasons of rice and a season of wheat when only a single climate stressor is modified from the baseline period. All stressors are then integrated to provide a best projection of combined production changes. Results indicate three distinct regions of climate impact, with primary impacts coming from heat waves in the northwest, river floods in the central portions, and sea level rise in the southwest.

In addition to the above results, the methodology of assessment is evaluated by examining the sensitivity of results to different integrating mechanisms. These include the use of ensemble and subset averaging vs. segregated scenarios, isolated assessments vs. comprehensive dynamic processes, and sub-regional vs. national scales.