Trends in urban climate changes in Sri Lanka: the case of the Colombo metropolitan region: final report

It is well recognized that global urbanization has rapidly intensified in recent years. By next year, global urban population is expected to outnumber the rural population (Oke, 1991). This trend is both new and unprecedented in human history. It is new because only in the recent past that global urbanization has intensified. Earlier episodes of urbanization confined only to certain areas of the world (for example, Europe and the North America after the industrial revolution). During the last 150 years, the global urban population has increased from a mere 3% in the 1850s (Detwyler & Marcus, 1972) to more than 45% in 1995 (World Resources, 1997). While the global population has increased six times during the last two hundred years, urban population has grown 128 times (cf. Schell, et al1993). Even though the global population growth rates seem to abate somewhat, global urbanization shows no sign of retreat (cf. World Urbanization Prospects, 1991). The changes caused by urbanization are unprecedented because humankind has no previous experience with such rapid transformation. The rapid global urbanization has brought in its wake many hitherto unknown changes to humans, other life forms and the physical environment. Changes caused by urbanization on humans include diseases associated with crowding (tuberculosis, pneumonia, respiratory illnesses, measles, common cold, etc.), air pollution-related illnesses and psychological and emotional disorders (cf. Harrison & Gibbs, 1976; Lake, et al., 1993). Urban effects on other life forms include physiological changes in urban flora and fauna and their diversity (Sukopp & Werner, 1982) and disease and growth retardation in vegetation (Stulpnagel, et al., 1990). Urbanization’s effects on the physical environment are apparent in air and water quality (Urban Air Pollution, 1992) and the microclimate (cf. Oke, 1987). Many of the changes brought about by urbanization are well studied by researchers in diverse fields such as medicine, agriculture and engineering. However, the physical effect of urbanization has not been understood nor the knowledge base applied, by urban designers, planners, and architects. In particular, the thermal comfort implications of the climatic changes induced by urbanization have received very little attention in urban design and planning. This is especially the case in tropical cities where urbanization is at its peak.Senate Research Gran