On rising temperature trends of Karachi in Pakistan

Abstract

Karachi is the largest city of Pakistan. The temperature change in Karachi is studied in this research by analyzing the time series data of mean maximum temperature (MMxT), mean minimum temperature (MMiT) and mean annual temperature (MAT) from 1947 to 2005 (59 years). Data is analyzed in three parts by running linear regression and by taking anomalies of all time periods: (a) whole period from 1947-2005; (b) phase one 1947-1975 and (c) phase two 1976-2005. During 1947 to 2005 MMxT has increased about 4.6 • C, MMiT has no change and MAT has increased 2.25 • C. During 1947-1975, MMxT increased 1.9 • C, in this period there is −1.3 • C decrease in MMiT and MAT has raised upto 0.3 • C. During 1976-2005, the MMxT, MMiT and MAT increased 2.7 • C, 1.2 • C and 1.95 • C, respectively. The analysis shows significantly the role of extreme vulnerability of MMxT in rising the temperature of Karachi than the MMiT.

Contemporary Temperature Fluctuation in Urban Areas of Pakistan

“…Climatic sensitivity of Bangladesh assessed by Siddik and Rahman [14] revealed a highly significant positive trend for annual mean and mean maximum temperature and significant positive trends were found for mean maximum and mean minimum temperature from June-November and November-February, respectively. Urban areas are affected globally by climate change; the temperature in Sao Paolo, Brazil, rose by 2 • C since 1993, and increasing temperature trends were found in Beijing, China, and the annual mean temperature in Seoul, Korea, increased by 1.5 • C during the last 29 years as mentioned by Sajjad et al [15].…”

“…Mega cities are responsible for higher carbon dioxide (CO2) emissions and contribution to the global gross domestic product. In addition, with an annual growth rate of 6.5% in the industrial zones and a rise in the number of vehicles from 0.8 million to 4.0 million, almost a 400% increase in the last few decades, Karachi consumes considerable energy and contributes CO2 and other emissions to the environment [15]. These cities have high urban population density and CO2 emissions according to GoP [28], as during the study period, the average population density rose from 80 to 220 people per square kilometre, and the CO2 emissions rose from 4 to 32 million metric tons ( Figure 2).…”

“…Prolonged monsoon rains and especially rainfall during the 1990's caused a strange negative trend in maximum temperature at Lahore Ahmad, Fatima, Awan and Anwar [18]. Karachi is an urbanized and industrialized economic hub, and Sajjad, Hussain, Ahmed Khan, Raza, Zaman and Ahmed [15] found increasing mean maximum and mean annual temperature with extreme variability during 1976-2005 and no change in mean minimum temperature. Ambreen et al [23] found a slightly rising, spatially severe varying temperature trend in December for the mountainous areas compared with the plain areas of Pakistan.…”

“…The annual temperature variation in urban areas is higher than in rural areas; urbanization and land use change initially influence the microclimate and minimum temperature of cities [4,9,10,15]. Therefore, analysis of local temperature is an important climatic factor to assess the climatic changes in the growing urban areas because of urbanization and industrialization.…”

An Assessment of Climate Change-Natural Disaster Linkage in Indian Context

“…Several studies have attempted to assess the effect of urbanization, industrialisation and mining activities on temperature trends [45][46][47][48][49][50][51]. It is assumed that large and densely populated urban, industrial and mining areas are key to temperature rise.…”