KARACHI:
Sindh province has witnessed prolonged heatwaves and its hottest May on record, with temperatures soaring as high as 50 degrees Celsius for consecutive days across many cities.
On May 26, the Mohenjo Daro weather station recorded a blistering 52.5°C, marking the highest temperature of the summer season so far. Jacobabad followed closely behind, reaching 52 degrees Celsius.
According to Chief Meteorologist Sardar Sarfaraz, areas including Jacobabad, Nawabshah, Sukkur, Rohri, Dadu, and Khairpur in upper and central Sindh experienced temperatures of 50°C from May 23 onwards, persisting for several days and leading to severe heatwaves. The mercury remained between 50 to 51 degrees Celsius in many areas until May 30.
The heatwave extended to lower Sindh, affecting cities like Hyderabad, Thatta, and Badin, where temperatures soared to 48°C in Hyderabad.
“In Meteorology lexicon, when 5 Celsius above the normal temperature retains for continuous 5 or 6 days it is called a ‘Heat wave’,” explained Sarfaraz. He clarified that although Karachi had experienced temperatures reaching 40 or even 41 degrees Celsius in the previous month, it did not qualify as a heatwave due to its brief duration.
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Sarfaraz also noted that Karachi residents feel the heat more intensely during periods of high humidity. For instance, with 50 per cent humidity in the air, temperatures of 36°C can feel like 40 to 42 degrees Celsius. Karachi witnessed several days above the average temperature in the previous month.
In contrast, many towns in upper Sindh experienced temperatures 8°C above the average for a week. Similar patterns were observed in Balochistan areas such as Sibbi and Jafferabad, leading to the declaration of heatwave conditions in some parts of central and southern Punjab.
Reflecting on past heatwaves, the devastating 2015 heatwave in Karachi claimed over 1,300 lives due to heatstroke within hours. However, the heatwaves of 2022 were more prolonged and severe.
In 2022, heatwaves were recorded as early as March, termed the “Early Spring heatwave.” A city in Punjab endured 45°C temperatures for 38 consecutive days. Pat Eidan in Sindh recorded temperatures 6 to 8 degrees above normal for the entire month.
The increase in heatwave conditions in Pakistan since the 1990s is believed to be attributable to climate change. In 2017, Mohen Jo Daro recorded a scorching 53 degrees Celsius, the highest temperature ever recorded in Pakistan. This record was surpassed by Turbat, Balochistan, in the same year, with a staggering 54°C, making it the second-highest temperature ever recorded in Asia and the fourth-highest globally.
Jacobabad, already known for its extreme temperatures, has crossed the deadly threshold for wet bulb temperature (TW), indicating dangerously high levels of heat and humidity. A study led by Tom Matthews at Loughborough University, UK, suggests that Pakistan may continue to set new heat records in the future.
Looking ahead, the Pakistan Meteorological Department (PMD) predicts above-normal rainfall during the upcoming monsoon season from June to August.
Positive Indian Ocean Dipole (IOD) conditions observed by meteorologists suggest normal to above-normal rainfall across most parts of the country, with significant increases expected in central and northern Punjab. Southern Sindh and Balochistan are also anticipated to receive above-normal rainfall, while Khyber-Pakhtunkhwa and Gilgit-Baltistan are expected to experience normal rainfall levels.