Understanding the Incremental Impact of Built Environment on Climate Change of Metropolitan City Karachi

Buildings are the most important part of development activities, consumed over one-thirds of the global energy. Household used the maximum energy around the world, likewise in Pakistan residential buildings consumed about half of total energy (45.9% per year). The study aims to analyze the impact of building design on climate of Metropolitan City Karachi, Pakistan and to evaluate the change in urbanization patterns and energy consumption in the buildings. To have better understanding of the issues correlations was established amongst population, urbanization patterns, green area, number of buildings (residential and commercial), building design, energy consumption and metrological records (climate change parameters) by collecting the data from the respective departments. With the help of the collected data amount of carbon dioxide was estimated. The results reveled that during last 36 years the urban population of Karachi increased exponentially from 5,208,000 (1981) to 14,737,257 (2017) with increase in urbanized area from 8.35 km(2) (1946) to 3,640 km(2) (2017) that may led to reduce the green area of the city from 495,000 hectors (1971) to 100,000 hectors (2015). Moreover, the building's design and numbers are being changed from 21 high-rise buildings (2009) to 344 (2017). It may be concluded that change in temperature pattern and climatic variability of the city may be due to increase in population and change in lifestyle that lead to high energy consumption that is prime source of increased in CO2 emission in the environment of Karachi city, However, Greenhouse Gases (GHG) releases are much lower than the levels reported from metropolitan cities around the world.