Climate-Responsive Architecture for Karachi: Passive Design Strategies for Thermal Comfort in a Hot Maritime Climate

Abstract

Karachi’s built environment is increasingly ill-adapted to its climate. Rapid, largely unplanned urbanisation  rising building density, the loss of green cover, and heat-retaining hard surfaces  has intensified the urban heat-island effect, and the deadly heatwave of June 2015, which killed well over a thousand people, made the human cost of that mismatch tragically clear. This thesis argues that climate-responsive architecture, grounded in passive design, offers a low-energy means of restoring thermal comfort in the city and of reducing the risk that extreme-heat events pose to life. It reviews the elements of climate and the mechanisms of human thermal comfort; characterises Karachi’s hot maritime (desert) climate and the climatic zones of Pakistan; and derives, from the physics of heat gain and loss and from precedent, a set of passive strategies suited to the city  building orientation and form tuned to the prevailing sea breeze, shaded and appropriately sized openings, cross-ventilation, thermal mass, reflective and insulated roofs, courtyards and semi-open spaces, and the cooling use of vegetation and water. The study concludes that by treating climate as a form-determinant rather than an afterthought, and by drawing on the lessons of Karachi’s older architecture, designers can produce buildings that are comfortable, economical, and resilient to a warming climate without heavy reliance on mechanical systems and fossil fuels.