Beyond heatwaves: It’s time for authorities to rethink their priorities when it comes to Karachi’s cruel summer

Taking heatwaves seriously is important, but addressing sustained chronic heat exposure is particularly critical.


Nabeel Ahmed

July 10, 2023

ISLAMABAD – Earlier this week, the world experienced the hottest day ever recorded globally, according to data from the US National Centres for Environmental Prediction.

The average global temperature reached 17.01 degrees Celsius, surpassing the August 2016 record of 16.92 degrees Celsius as heatwaves sizzled around the world.

Even as the entire world reels from the effects of rising mercury, heat experiences in South Asia are all the more dynamic and complex. Humidity in this region makes experiences of heat quite different from other regions and decades of anti-poor urban planning, coupled with infrastructural violence, has rendered people even more vulnerable to the impacts of climate change.

In humid regions like Karachi, cooling options are restricted. Being indoors may feel equally, if not more hot than outdoors. Thus, temperature alone is not an accurate indicator of the magnitude of heat exposure.

According to the Intergovernmental Panel on Climate Change (IPCC)’s sixth assessment report, across sectors and regions, the most vulnerable people and systems that have been disproportionately affected by the impacts of climate change also have high vulnerability to climatic hazards, with global hotspots of high human vulnerability observed in South Asia.

With about 2°C warming, climate-related changes in food availability and diet quality are estimated to increase nutrition-related diseases and the number of malnourished people, affecting hundreds of millions of people, particularly among low-income households in low and middle-income countries in sub-Saharan Africa, South Asia and Central America.

Urbanisation and climate change interact to drive an urban heat island (UHI) effect across Asian cities. Trends in heatwave frequency, duration and cumulative heat have accelerated since the 1950s. Extremes of wet-bulb temperature — the lowest temperature to which air can be cooled by the evaporation of water into the air at a constant pressure — in South Asia are likely to approach, and in a few locations, exceed this critical threshold by the late 21st century if greenhouse gas emission levels are to continue on the current trajectory.

According to a report published by the University of Bristol, ‘Impacts of 1.5°C Global Warming on Natural and Human Systems’, the impact of heatwaves at these warming levels on cities will be significantly greater than under the present climate conditions. Various research studies have show that particularly in South Asia, more intense heatwaves of longer durations and higher frequencies are expected in India and Pakistan. At the city level, these projections could translate into devastating impacts, such as the 2015 record heatwaves in Karachi.

Heat in Karachi

At the beginning of April 2023, the Pakistan Meteorological Department (PMD) had predicted the temperature of Karachi to increase by 3-4°C. In April, the temperature of the city reached 39.7°C and the maximum temperature till the end of May was 39°C. Although these days were not considered to be a heat wave, they can definitely be considered as ‘hot days’, due to the heat and humidity in the air.

Now if we look at the statistics, it is clear that the summer season in Karachi will be extremely hot this year as the temperature in the month of February was higher than normal. But have our institutions and people prepared themselves for the coming summer? This is the time for officials, government agencies, disaster response organisations and citizens alike to be vigilant and to protect themselves from expected extreme temperatures.

If one compares Karachi today with 20 years ago, a clear rising trend in mercury levels can be seen, reflecting the rapidly warming climate in the city. According to a recent study conducted by the Karachi Urban Lab (KUL) — an interdisciplinary, collaborative platform of research in Karachi — since 1960, night time temperatures in Karachi have increased by about 2.4°C, while daytime temperatures have increased by 1.6°C.

According to the IPCC, in 2021, the global average increase in temperature since 1900 was 1.1°C, and compared to this, the rate of temperature increase in Karachi is particularly high. The summers are longer and more intense due to the abnormal increase in temperature.

As global temperatures continue to rise, the deadly effects of extreme heat are becoming increasingly apparent. Since 2015, Karachi has experienced at least five extreme heat waves, the details of which are as follows.

"Beyond heatwaves: It’s time for authorities to rethink their priorities when it comes to Karachi’s cruel summer"

Five major heatwaves in Karachi from 2015-2021. There may be variations in the temperature records and estimated loss of life, as these figures are collected from different sources, hospitals and media reports.

It is worth noting that these are just a few of the most notable heat waves that have affected Karachi. In the 2015 heat wave, the city’s hospitals and cemeteries were overcrowded, with no room for patients. There were no morgues to house the dead, the city’s cemeteries were in disarray and understaffed, with corpses waiting to be buried. Unofficial figures put the death toll at more than 6,000. There was a shortage of ice for cold water and the cost of a piece of ice for cooling dead bodies shot up significantly.

The heat factor goes unquestioned

There are also issues that neither institutions nor the public give importance to — such as the increase in the severity of various diseases and illnesses due to rising temperatures. The deaths caused by these diseases are not considered an effect of heat waves. It is also difficult to accurately estimate the number of deaths caused by heat waves, as many go unreported or are attributed to other causes.

Above all, there is no clear method to determine the exact cause of death in extreme heat and related diseases. We don’t even have statistics on how many people in this city of 30 million people get sick from extreme heat, let alone chronic heat that complicates various diseases and often shortens the life span of patients.

Public institutions seem to be unable to understand or grapple with the serious effects of heat. There are many densely populated areas where resources for health services and facilities are negligible or for which travel time to major public hospitals in the city is hours at best. If people living in these areas are exposed to the effects of extreme heat, they do not even get time to reach a hospital, thus increasing heat-related risks.

Experiences and events ranging from rising temperatures to extreme heat waves must be understood as slow-onset disasters. They affect daily life, productivity, health, and well-being. The humidity in Karachi’s air further complicates the issue, because the perceived temperature (feel-like temperature) is much higher than the actual temperature in the air. A careful analysis of chronic heat exposure and heat stress is essential if we are to develop and implement successful heat stress and heat management plans.

According to World Health Organisation (WHO), “heat cramps, heat exhaustion, heatstroke, and hyperthermia are just a few of the disorders that can develop when the body’s capacity to regulate temperature is compromised by rapid increases in heat gain brought on by exposure to hotter than usual temperatures.” Extreme heat events can be dangerous to health, even fatal.

These events result in increased hospital admissions for heat-related illness, as well as cardiovascular and respiratory disorders. Extreme heat events can also trigger a variety of heat stress conditions, such as heat strokes. Research shows that chronic heat exhaustion, sleep disturbances and susceptibility to minor injuries and illnesses have all been attributed to the possible effects of prolonged exposure to heat. People with chronic conditions who take daily prescriptions, as well as the elderly and young, are at a higher risk of complications and mortality during a heatwave.

Attention to the adverse effects of heat on individuals, especially the immunocompromised and vulnerable such as the elderly, children, and those with pre-existing diseases, is the need of the hour. These include increased risk of heat-related illness, worsening respiratory and cardiovascular conditions, reduced productivity and economic impact, and reduced quality of life.

Where do we go when our homes are burning?

According to KUL researchers, discussions with residents of densely populated neighbourhoods in Karachi revealed that homes do not provide refuge from extreme heat. Often, when emergency warnings are sent out, instructing people to remain indoors, it does not take into account that homes themselves turn into hot ovens, which can be very dangerous, and that many people from low income groups do not have access to cooling equipment.

These temporal and thermal inequalities are also linked to class inequalities. If homes become overheated, it may be hotter to stay inside and people may prefer to remain outdoors. Even on days that are not declared to be ‘heat waves’, temperatures can be dangerously hot. So this leads us to the question: if it’s not a heat wave then what is it? It is chronic heat. This leads into the larger idea that I want to put forward: we need to think beyond heat waves.


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Even though it’s very hot in Karachi, the government is not considering the impacts of extreme heat and chronic heat exposure on the lives of ordinary citizens, outdoor workers, elders, and people who are already dealing with different diseases.

While institutions advise people to take necessary precautions to avoid heat-related diseases, what is to be of the workers made to work outdoors? There is no legislation in this regard. It is also advised to drink water continuously and stations are set up where people are made to drink a gallon of water. However, this sometimes requires waiting in a queue under the sun for hours.

Government agencies should take this issue seriously and take pre-emptive measures to curb the impact of future heatwaves, especially to mitigate the risk of chronic exposure. At least during expected extreme heatwaves, they must ensure uninterrupted supply of electricity and water, availability of ice in low-income settlements as well as water for ice factories, umbrellas in crowded public places, designated working hours for the working class, and arrangements from hospitals to small dispensaries to care for patients suffering from the effects of extreme heat.

Meanwhile, it is also important to promote afforestation as much as possible with environmental conservation campaigns to reduce the impact of heat waves. Addressing the devastating effects of heatwaves requires a multi-pronged approach that includes education and awareness, access to water, electricity and sanitation, infrastructure improvements and political will.

Authorities need to look beyond emergency responses and think long term. Taking heatwaves seriously is important, but addressing sustained chronic heat exposure is particularly critical. Its effect is compounded in cities like Karachi by deteriorating infrastructure and limited access to basic necessities, which reduces people’s ability to cope with heat.

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