Pakistan to witness more intense heat wave incidents in coming years


ISLAMABAD: Federal Minister for Climate Change, Senator Mushahidullah Khan, has warned of more extreme heat wave incidents in future in different parts of the country, particularly urban areas.

“However, we need to prepare now to cope with negative impacts of heat wave incidents, which more likely to become more frequent and intense in future,” the minister stressed stressed during a press conference on the launch of the ‘Heat Wave report’.

A sever heat wave struck the country in June this year, which caused high number of causalities, especially in Karachi. Most of the country was under the grip of heat wave during 17 to 24 June. As on 20th June, high temperatures were recorded in the southern parts of the country. The temperature ranged from 49 degree Celsius in Larkana and Sibi to 45 degree Celsius in Karachi. In southern Punjab, 40 degree Celsius was recorded in Multan, whereas several areas of the Balochistan province were also affected where temperature touched 49 degree Celsius in Sibi and Turbat. Late in June, the minister Mushahidullah Khan had formed a committee of experts to investigate the causes of the blistering heat wave in the country, so that fallouts of heat waves in future are mitigated.

The expert heat wave group comprised former director general of Pakistan Meteorological Department, Dr. Qamar uz Zaman Chaudhry, DG Pakistan Meteorological Department Dr. Ghulam Rasul, Member DRR, National Disaster Management Authority Mr. Ahmad Kamal, Director-General DG, National Health Emergency Preparedness Mr. Munir Ahmad Mangrio, Senior Scientist of the Global Change Impact Studies Centre Mr. Shahbaz Mahmood, and representatives from Provincial Disaster Management Authorities.

Talking about causes of the recent heat wave in different parts of country, particularly Karachi, Mushahidullah Khan told media that the summer afternoons in Karachi during the month of June 15-16 displayed a typical normal moisture quantity and transport into the area from the Arabian Sea. The atmospheric conditions went anomalous after a ridge (extension of high pressure area) was extended over Balochistan and adjoining parts of the country including Karachi.

The formation of this ridge led to a weakened incoming sea breeze transport process from the Arabian Sea and consequently reduced the humidity levels below normal over Karachi on the afternoon of 17th June, 2015. The ridge further accentuated on 18th June and penetrated more into south and eastward parts of the country, he added.

“The analysis of the lower atmosphere (1500 – 3000m above sea level) reveals that due to a low pressure area over northeastern parts of India and a shallow low over southeastern parts of Pakistan, the wind direction over Karachi remained northwesterly, which brought dry and modified warm air to Karachi. Similarly at 500 hPa (5000 m above sea level), as a result of a low pressure area over northeastern parts of India the direction of winds passing over Karachi were northwesterly which also contributed in bringing dry and modified warm air to Karachi,” he explained further.

Lead author of the report, former director general of the Pakistan Meteorological Department, Dr Qamar-uz-Zaman Chaudhry, said that the atmospheric conditions mentioned above were the main cause of severe heat wave. Other factors like, persistent and somewhat unplanned urbanization, deforestation, lack of green areas, open spaces, lack of hygiene practices, awareness, green building and roads materials and transportation systems created heat island effect which added up to the extreme temperatures.

“Frequent and prolonged power outages, water supply constraints further decreased the capacity of inhabitants to combat adverse impacts of heat wave which resulted into historically an unprecedented large number of casualties in Karachi,” he added.

Chaudhry said further that a cyclonic system started to develop over the Sea on June 18, which concentrated into a depression on June 22, moved northeastwards, entered through Saurashtra and Kutch (India) on June 24, weakened into a low pressure area. It further moved northeastwards and laid over West Rajasthan (India) on June 25 June.

“Prolonged presence of this low pressure system in the vicinity of Sindh-Makran coast further reduced the flow of sea-breeze. The system further strengthened and blocked all the moisture transport and ventilating winds towards Karachi,” he elaborated.

Giving further details, the Director General of the Pakistan Meteorological Department, Dr Ghulam Rasul, said that due to the low pressure area over northeast Arabian Sea, surface wind of Karachi during morning to early afternoon remained easterly/northeasterly during the heat wave period which brought extensive hot and dry air from Rajasthan (India) through heated land of Sindh, whereas surface wind in the late afternoon (1200 UTC) remained mostly westerly/southwesterly which brought lot of moisture, ultimately increasing the amount of humidity.

“Meanwhile due to the low pressure areas of northeast Arabian Sea and Bay of Bengal/northeast India, the upper air wind pattern over Karachi remained northeasterly/northwesterly which brought dry and modified warm air together with the hot and dry wind of the surface in the morning and early afternoon rose the temperature appreciably and moist westerly/southwesterly wind in the late afternoon increased the humidity, as a result, the temperature which was already higher fell much more than the actual recorded one both for day and night times. The weakening of low pressure system over Arabian Sea on the afternoon of June 24-25 rendered a usual moisture intrusion into Karachi,” he said.

The expert group, who hammered out the heat wave report, have emphasized in the report that the recent worst heat wave spell in the country demands a comprehensive strategy to cope with disastrous heat waves.

However, they have recommended that an effective early warning system for heat waves as discussed above may be established in the country on a priority basis. For this purpose a detailed survey should be conducted to locate and map the heat wave prone areas in the country with all vulnerabilities, risks and possible scenarios, they stressed.

They also underline the need for capacity of individuals and communities may be built to respond to the heat stress during heat waves by raising heat-health awareness campaigns in the country before the onset of a heat waves season.