‘Climate change threatens extreme weather for Sindh and Balochistan’

Karachi and the adjoining coastal areas of Sindh and Balochistan may have to endure torrential rains in the monsoon season for years due to frequent tropical cyclones in the Arabian Sea.

Talking to The News on Sunday, Pakistan Meteorological Department chief Dr Ghulam Rasool attributed the impending bad weather to the constant rise of temperature of the Arabian Sea in summers due to global warming.

“In South Asia, tropical cyclones usually formed in the Bay of Bengal because its temperature remained higher than that of the Arabian Sea,” said Dr Rasool. “But for the past two decades, the Arabian Sea is getting as warm as the Bay of Bengal due to climate change.”

Meteorologists have been witnessing changing weather patterns in the Arabian Sea due to global warming, where the sea level temperature is rising and low pressure areas or depressions are forming, with the potential to transform into tropical cyclones off the Sindh-Makran coast.

“The Arabian Sea’s temperature is now higher than or equal to the temperature of the Bay of Bengal, and climatic conditions are suitable for tropical cyclone formations off the coasts of Karachi and Balochistan,” said Dr Rasool, adding that depressions – the early stages of tropical cyclones – could convert into sea storms more frequently.

He said that while the frequency of rain was likely to decrease, their intensity was expected to increase along Pakistan’s coastline, adding that the rise in the Arabian Sea’s temperature would also affect the coastal areas of Sindh and Balochistan in the monsoon season.

“Tropical cyclones cause severe rains and bring strong winds when they make landfall on coasts, just like the Severe Cyclonic Storm Mora did in Sri Lanka and Bangladesh last week.”

Mora was the severest tropical cyclone to hit Bangladesh this May before causing the most large-scale devastation in Sri Lanka since 1994, killing hundreds, displacing millions and damaging properties worth billions in the coastal areas of the two countries.

Tropical cyclones in the Arabian Sea move mostly towards India’s westernmost state of Gujarat, but they rarely make landfall in the coastal areas of Sindh, including Keti Bandar, and sometimes near Karachi or in Balochistan’s coastal areas.

But the Met Office chief hinted at changing monsoon patterns and more rains in the coastal areas of Sindh, including Karachi, and the coastal towns of Balochistan after formation of more tropical cyclones. He urged the authorities to develop climate-resilient infrastructure considering future climate change scenarios.

“Even if a tropical cyclone forming in the Arabian Sea does not make landfall on or near Karachi’s coast, it can bring heavy rainfall in the city, where the infrastructure is not capable of enduring more than 50 to 60 millimetres at a time.”

Situation in Karachi

Dr Rasool said low pressure areas formed in the Arabian Sea were reversing wind flow from land towards the sea because of which Karachi witnessed block in sea breeze and rise in temperature and humidity, resulting in heatwave-like conditions.

“A low pressure area formed in the Arabian Sea in June 2015 had caused a severe heatwave because it remained stationary south of Karachi’s coast for four to five days and blocked sea breeze to the city. Starting this Ramazan, a low pressure area did the same thing, but due to a large distance from the coast, its influence was not as strong as two years ago.”

Dr Moazzam Ali Khan, Marine Fisheries Technical Adviser for the World Wildlife Fund-Pakistan, also predicted more severe heatwaves for Karachi in the coming days, saying that although the maximum temperature was not increasing in the city, the gap between the maximum and minimum temperatures was reducing, which was “unusual and an uncomfortable phenomenon” for the locals.

He claimed that compared to wet spells, dry spells would stretch in the metropolis because of changing weather patterns, saying that instead of having a week-long wet spell, the city might witness cloudbursts, which could cause flooding in urban areas.