Climate woes in Pakistan as global temperatures rise
Temperatures have been hovering around 40 degrees Celsius in most parts of Pakistan for the better part of May and this trend is set to continue through June. The southern city of Nawabshah recorded a high of 50.2°C on May 2.
With intermittent power shut-downs and irregular supply of water during the month of Ramadan, there has been no reprieve for the people in Pakistan.
So far, heat waves have claimed more than 60 lives in Karachi where the temperatures were recorded at 44°C in early May. Similar temperatures are being recorded in Lahore and expected to further rise by 4°C to 5°C in the coming months.
Heat waves are the most damaging climate extremes to the human society and have a potential to result in a substantial increase in human mortality. For every 1°C in temperature during a heat wave, there is a 7.9 percent increase in mortality risk. Climate simulation models constantly project the frequency, severity and duration of heat waves will increase over this century.
Episodes of extreme temperature are associated with significant impacts on the health and hence present a challenge for public health. Human populations are acclimatized to their local climates, in physiological, behavioral, and cultural terms. However, there are limits to the amount of heat exposure an individual can tolerate. Unusually high temperatures over several days in succession, when there is relatively little night-time cooling, are mostly associated with an increased incidence of heat-related mortality.
Healthy adults have an efficient heat regulatory mechanism, which copes with increases in temperature up to a certain threshold so that even when there are considerable fluctuations of temperatures, it maintains a constant “core” body temperature. Severe heat stroke occurs when the core body temperature exceeds 40°C and leads to multiple organ dysfunctions. High temperatures cause the clinical symptoms of heat stroke, heat exhaustion, heat syncope, and heat cramps. Vulnerability to heat waves increases with age due to changes in a person’s thermo-regulatory system. Hence, elderly people with other co-morbidities, children below the age of five, and men who are involved in outdoor labor are more prone to heat-related mortality.
The Global Climate Risk Index places Pakistan at number 7 on their list of 10 most vulnerable countries affected by climate change.
Mehreen Mujtaba
Low socioeconomic conditions and deprivation, especially among urban slum dwellers, also increase the risk of heat-related deaths.
Four meteorological variables significantly affect the thermoregulatory system of the body. These are air temperature, humidity, air motion and solar radiant heat energy. High humidity combined with high temperatures limit the cooling effect of evaporation of perspiration and as such leads to heat stress.
The most important local climate change due to human building activities is the so-called urban heat island (UHI) - which is a metropolitan area that is much warmer compared to its surrounding rural areas. Research for more than half a century has shown the importance of this phenomenon that is caused by the storage of shortwave solar energy in the buildings during the day and its release by longwave radiation in the evening and at night. The larger the city and the denser its build-up structure, the more intense is the city’s heat archipelago. Hence megacities, like Karachi are more vulnerable to heat waves.
The Global Climate Risk Index places Pakistan at number 7 on their list of 10 most vulnerable countries to be affected by climate change, which translates to experiencing more frequent, prolonged and severe heat waves along with other climate change related calamities. In view of this observation, the country is in dire need of a comprehensive strategic plan to cope with future periods of heat wave. The government can tackle the issue of climate-related heat waves through policy development, regulation and urban planning. Before the start of the summer months, it is imperative to develop two-tier strategies, both at the federal and provincial levels, to increase public awareness through heat alerts, capacity building of communities through heat-health awareness campaigns as well as emergency response readiness.
In addition, increasing green spaces and planting indigenous shade-providing trees, which grow quickly will shift the skewed balance between concrete buildings and vegetation, hence combating the urban heat island effect.
In order to confront this burgeoning problem, it is imperative that the government, private sector, civil society, media as well as community representatives all sit together to come up with innovative ways, in accord with their local and cultural practices to tackle the issue.
Besides highlighting the effects of climate change, we must also address the root causes of the problem. In so doing, we will discover how the benefits of assuming moral responsibility and taking immediate action far outweigh the cost of remaining nonchalant and passive.
- Dr. Mehreen Mujtaba is a freelance consultant working in the areas of environment and health.
