The effectiveness of wetlands in reducing urban heat during the pre-monsoon season in Bangladesh: a case study of Sharoboriya wetland in Dhaka city

Dhaka’s urban growth and unplanned landcover changes have severely degraded natural wetlands. This study monitored pedestrian-level air temperature along three routes of varying building density around the Sharoboriya wetland during the 2025 pre-monsoon season, alongside a resident perception survey (n = 150). Sharoboriya wetland is a key nature-based solution to microclimatic cooling, showing a maximum cooling effect (ΔT) of 4.4 °C. But this cooling is highly dependent on urban land use. Open, low-density corridors have more cooling effects, while high-rise residential routes remained weak even immediately adjacent to the wetland. The resident perception of cooling and preference to live near the wetland both had a peak at 100–200 m, rather than at the edge of the wetland, as does the physical cooling pattern. This indicates that wetland cooling benefit in Dhaka is actively constrained by unplanned urban growth. So, protecting remaining wetlands alone is insufficient without managing the land use around them properly.