Spatiotemporal changes in temperature projections over Bangladesh using multi-model ensemble data

Abstract

Temperature rise is a concern for future agriculture in different regions of the globe. This study aimed to reveal the future changes and variabilities in minimum temperature (Tmin) and maximum temperature (Tmax) in the monthly, seasonal, and annual scale over Bangladesh using 40 General Circulation Models (GCMs) of Coupled Model Intercomparison Project Phase 5 (CMIP5) for two radiative concentration pathways (RCPs, RCP4.5 and RCP8.5). The statistical downscaling climate model (SimCLIM) was used for downscaling and to ensemble temperature projections (Tmax and Tmin) for the near (2021–2060) and far (2071–2100) periods compared to the base period (1986–2005). Multi-model ensemble (MME) exhibited increasing Tmax and Tmin for all the timescales for all future periods and RCPs. Sen’s slope (SS) analysis showed the highest increase in Tmax and Tmin in February and relatively less increase in July and August. The mean annual Tmax over Bangladesh would increase by 0.61°C and 1.75°C in the near future and 0.91°C and 3.85°C in the far future, while the mean annual Tmin would rise by 0.65°C and 1.85°C in the near future and 0.96°C and 4.07°C in the far future, for RCP4.5 and RCP8.5, respectively. The northern and northwestern parts of the country would experience the highest rise in Tmax and Tmin, which have traditionally been exposed to temperature extremes. In contrast, the southeastern coastal region would experience the least rise in temperature. A higher increase in Tmin than Tmax was detected for all timescales, signifying a future decrease in the diurnal temperature range (DTR). The highest increase in Tmax and Tmin will be in winter compared to other seasons for both the periods and RCPs. The spatial variability of Tmax and Tmin changes can be useful for the long-term planning of the country.

Thermal Bioclimatic Transformations in the Coastal Regions of Ganges Delta: Insights from CMIP6 Multi-Model Ensembles

“…The eleven indicators convey signi cant information about various temperature conditions closely associated with the biology and ecology of the coastal region of the GD. The study's ndings that the average temperature (Bio-1) would rise by 0.93-2.02°C for SSP245, while 1.21-3.63 for SSP585, are consistent with the ndings of earlier works 4,40,41 . DTR (Bio-2) and Isothermality (Bio-3) are expected to decrease in the study region, which also coincides with the studies conducted by the MME of CMIP5 40 and CMIP6 4 GCMs.…”

Impacts of climate change on diarrhoeal disease hospitalisations: how does the Global Warming Targets of 1.5 - 2°C affect Dhaka, Bangladesh?

“…Using statistical downscaling model, one study predicted an increase of 2.7°C and 2.1°C in average annual maximum and minimum temperature per century [28]. Using multi-model ensemble (MME) of 40 CMIP5 GCMs, a recent study showed that mean annual maximum temperature over Bangladesh will increase by 0.61-1.75°C in the near future (2021-2060) and 0.91 – 3.85°C in the far future (2071-2100) [14]. Given that different climate projections suggest a variable increase in daily temperature across Bangladesh ranging between 0.91 – 4.3°C by the 2100s and because climate projections are prone to biases [9], we estimated the increased risk of diarrhoea under various projected temperatures.…”

“…Bangladesh is a low- and middle-income country (LMIC) in Southeast Asia with a low-lying topography, poor infrastructure and high population density [14]. Bangladesh has been classified in the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) as a country that is highly vulnerable to the adverse impacts of climate change [1].…”

“…A recent study projected over a 10% rise in heat-related diarrhoeal diseases in the Gaza Strip, Palestine under the 2 °C global warming scenario [13]. Bangladesh is a low-and middle-income country (LMIC) in Southeast Asia with a low-lying topography, poor infrastructure and high population density [14].…”

“…Bangladesh has been classified in the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) as a country that is highly vulnerable to the adverse impacts of climate change [1]. As temperatures continue to rise and rainfall becomes more erratic, water stress and food insecurity may increase in Bangladesh [14]. Though Bangladesh has made strong progress towards ensuring better quality drinking water-the switching to improved water infrastructure-much of what is tapped remains contaminated with dangerous microbes, heavy metals, or salt.…”