KARACHI: Is Karachi experiencing climate change? Where is all this heat coming from? How can the heat kill people in hundreds? Baffled Karachiites are wondering what is happening to the weather patterns in their city but the recent heat wave may not have come as unannounced as some of us think.

Scientists have warned for some time now that heat waves will become more frequent and intense due to climate change, yet the government is yet to recognise this impending threat.

Death toll from the ongoing heat wave across Karachi, which was amplified by high humidity, load-shedding and low water consumption as people are fasting, has now risen to above 700.

Currently, hundreds of patients suffering from heat stroke and heat exhaustion are being treated by government and private hospitals in Karachi. And it is a fact that many of these deaths could have been avoided if the government had given early warnings in relation to the heat wave and had provided people with increased access to clean drinking water.

What caused the heat wave in Karachi

The weeks leading to the start of monsoon season are usually the warmest of the year throughout Pakistan. Karachi, being on the Arabian Sea coast is blessed by sea breeze which moderates the city’s weather.

During the past week, due to a low-pressure system out at sea, the sea breeze has not flown towards the city leading to a spike in temperatures, Dr Ghulam Rasul, Director General of Pakistan’s Meteorological Department (PMD), says.

“A low pressure system developed over the Arabian Sea, and the windsblew towards the low pressure area, from the coast to the sea. Thewind flow pattern reversed, as winds blew to fill up the lowpressure area developing over the sea”.

Sea breeze moderates temperatures in Karachi, which would rise to between 45 and 50 degrees Celsius in May and June, says Dr Rasul, adding that “a low pressure system over the Arabian Sea is a normal feature for the months of May and June, and it will not last more than four days.”

The pre-monsoon season was slated to arrive on the night of June 23 with approaching winds and it is likely that Karachi and the rest of the country will receive rainfall in the coming days.

Dr Rasul moreover suggests that “the monsoon incursion entering from the south of the country will run across Sindh and Balochistan, while another monsoon current will enter from the north of the country through Azad Kashmir, bringing rainfall to northeastern Punjab, Rawalpindi, Malakand, Nowshera and will continue southwards to Sargodha and Lahore.”

Is Karachi experiencing climate change?

The PMD’s Director General however does not see a link between the current heat wave battering Karachi and climate change.

This is in contrast with the views of Dr Qamaruz Zaman Chaudhry, a former head of the PMD and now a climate change expert in Pakistan, who says that the heat wave is “unusual” and is “one of the manifestations of climate change”.

Dr Chaudhry authored Pakistan’s first National Climate Change Policy. He stresses upon the fact that “rising temperatures resulting in enhanced heat and water-stressed conditions, particularly in arid and semi-arid regions, will lead to reduced agricultural productivity”.

Climate change contributes to major survival concerns for Pakistan, particularly in relation to the country’s water, food and energy security, but how much of these challenges are manageable and up to which degrees are some questions that need exploring.

As for the ongoing heat wave in Karachi and the casualties that it has resulted in, Dr Chaudhry says that the government should have been on alert beforehand and should have provided timely advice to citizens on how to deal with the extreme weather conditions.

“Outdoor activities should have been restricted, particularly all labour activities until the heat wave had subsided,” the former PMD chief says.

Warmer summers, milder winters

Another expert, Dr Mohsin Iqbal from the Global Change Impact Study Centre in Islamabad, has pointed out that the rise in temperature in Pakistan is higher than the average global temperature increase.

“There has also been an increase in climate induced extreme events – an increase in heat waves, droughts, floods, cyclones and wildfires. In Pakistan, the frequency and intensity of extreme events has increased; there were super floods in 2010 and 2011 and back-to-back floods in 2011, 2012, 2013 and 2014. There have been droughts, intense heat waves and severe cyclonic storms in the country,” explains Dr Iqbal, adding that all aspects of food security are potentially affected by climate change.

He is the only scientist from Pakistan to contribute to the latest scientific report of the Intergovernmental Panel on Climate Change (IPCC) that was released in 2014.

The IPCC report says that “global climate change is likely to be accompanied by an increase in the frequency and intensity of heat waves, as well as warmer summers and milder winters”.

Impact of extreme heat on human health

With hundreds of Karachiites becoming casualty to the ongoing heat wave, understanding weather patterns and how they may be affecting our health and quality of life is becoming increasingly important, particularly as the latest IPCC report says that “the impact of extreme summer heat on human health may be exacerbated by increases in humidity".

The report says that "excess mortality during heat waves is greatest in the elderly and people with pre-existing illness".

"Much of this excess mortality from heat waves is related to cardiovascular, cerebrovascular and respiratory disease. The mortality impact of a heat wave is uncertain in terms of the amount of life lost; a proportion of deaths occur in susceptible persons who were likely to have died in the near future. Nevertheless, there is a high level of certainty that an increase in the frequency and intensity of heat waves would increase the numbers of additional deaths from hot weather. Heat waves are also associated with nonfatal impacts such as heat stroke and heat exhaustion,” the report explains in detail.

Heat waves also have a much greater health impact in urban areas than in surrounding suburban and rural areas. This is because urban areas typically experience higher temperatures because of the "heat island" effect.

Given the rising average global temperature, it is expected that extreme heat waves will become more common worldwide. The past year, 2014, has been ranked the warmest year on record, driven by the accumulation of heat-trapping greenhouse gases in the atmosphere.

However, 2015 is not too far behind. Nine of the 10 hottest years on record have all occurred in the 21st century.

How Ahmedabad prepares for heat waves and what Karachi can learn

Certainly, mortality during a heat wave can be prevented.

After a heat wave in 2010 killed an estimated 3,000 people in the Indian city of Ahmedabad, the administration established a “Heat Health Action Plan” that raised awareness of health risks from extreme heat among citizens and trained healthcare workers to recognise signs of heat stress.

City officials there realised that coordinated action was needed to prepare for the rising threat of extreme heat and scientists worked to develop a forecast system that could alert the administration to impending heat waves several days out.

Perhaps officials in Karachi can learn from the example of Ahmedabad in order to prepare for future heat waves, which scientists say are all too likely.