Dhaka, a megacity which is also ranked as the world’s second least livable city With a cost of living as high as Montreal.It has experienced an average annual growth rate of 7% both horizontally and vertically leading to its rapid expansion.
Climate change comes hand in hand with unplanned and haphazard urbanization such as that of Dhaka city creating a UHI in the process. An urban heat island, or UHI, is a metropolitan area that’s a lot warmer than the rural areas surrounding it. Heat is created by energy from all the people, cars, buses, and trains in big cities like New York, Paris, and London. Urban heat islands are created in areas like these: places that have lots of activity and lots of people. UHI’s have poor air and water quality because of the presence of more pollutants in the air and water which are then blocked from scattering to reduce the toxic effect by the congested nature of the urban infrastructure. Scientists say that UHI contributes to global warming as well by contributing to the gradual warming of the Earth’s temperature.
In the summer, people living in the urban areas have to resort to fan or air conditioning especially where there is a presence of UHI.This in turn leads to higher energy demands in the summer and often leads to power outages if the city doesn’t have the proper infrastructure to support the upsurge in energy demands. So, the energy used to operate the air conditioning contributes towards UHI as well.According to the Intergovernmental panel on climate change (IPCC) the global surface temperature has increased 0.74 ± 0.18 °C during the last 100 years ending in 2005 1. The effect of climate change will be very much severe for the megacities mainly in the Asian megacities of the developing world due to a large number of population concentration.
(ref-9).Approximately 48% of the world population lives in urban areas and they are directly exposed to urban heating and this number is only expected to grow as more and more people are starting to live in urban areas (5 billion by 2030). This study has concentrated on the change in the temperature pattern on the historical data of Dhaka the only megacity of Bangladesh from 1995-2010 to know the recent changes in the temperature pattern of Dhaka city.