Heatwaves can pose serious health risks. Learn how to cope with extreme heat, protect yourself, and recognize heat-related illnesses at Meri Sehat.

Heatwaves And Its Implications

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ZAKA CLINIC GULBERG LAHORE

Saad Ullah Siddiqui

Overview

For the West, summer signifies beach plans, barbeques, and fun in the sun. But for those living in the subcontinent, summer brings with it heat stress, load-shedding, lack of water, a surge in diseases, and many more surprises. These surprises seem to be occurring earlier and earlier every year thanks to climate change.

We humans often forget that our actions have long-term consequences. There is no better example of this than climate change. Over the years, human activities have led to long-term shifts in the planet&rsquo;s temperatures and weather patterns, affecting millions across the world. The burning of fossil fuels like oil, gas, and coal to generate energy is considered the main cause of climate change. Other factors such as the clearing of forests and industrialization also play a role.

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According to the Intergovernmental Panel on Climate Change (IPCC), the earth&rsquo;s global surface temperature has increased by 1.0 &deg;C<a href="#accordion">[3]</a>. This is expected to rise further by 1.1-6.4 &deg;C. Furthermore, climate change has caused large parts of South Asia to experience periods of extreme heat earlier than normal<a href="#accordion">[1]</a>. The region has become at least 2 degrees Celsius hotter and the risk of heatwaves is 30 times higher<a href="#accordion">[2]</a>.

Since Pakistan is a low income country with limited resources, it is more at risk of the effects of climate change. It currently ranks 7th on the list of top 10 countries with a 30.5 climate risk index score<a href="#accordion">[4]</a>. According to Amnesty International, between March and May 2022, Pakistan reported some of the highest temperatures in the country in the last 60 years<a href="#accordion">[5]</a>. The rising temperatures pose a threat to not just the country&rsquo;s public health but also the infrastructure and economic stability. Rapid melting of Himalayan glaciers, increased monsoon variability, flash floods, unprecedented heatwaves, and droughts are just some common implications of climate change in the country. 
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Scientists define heat waves as prolonged periods of extremely high temperatures in a particular area<a href="#accordion">[6]</a>. They can last for several days to weeks, and the temperatures in the area are way above the average for that location.

According to the World Health Organization (WHO), heatwaves claimed more than 166,000 lives between 1998 and 2017<a href="#accordion">[8]</a>. Additionally, the number of people exposed to heatwaves increased by 125 million from 2000 to 2016<a href="#accordion">[8]</a>. With extreme temperature events increasing in duration, frequency, and intensity, these numbers are expected to rise further.

The impact of heatwaves is generally higher in cities due to the urban heat island effect causing a 3.5 &deg;C&ndash;12&deg;C&thinsp;higher temperature than neighboring areas<a href="#accordion">[6]</a>. In Karachi, temperatures can reach a high of 45&deg;C between May and July<a href="#accordion">[4]</a>. In 2015, the city experienced a devastating heatwave that claimed more than 1,200 lives in just 4 days<a href="#accordion">[4]</a>.

Since 2016, the frequency of heat waves has been growing across the subcontinent. Moreover, these heat waves now last longer, especially in India and Pakistan<a href="#accordion">[7]</a>. 
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Causes

Climate change and global warming are one of the major causes of heatwaves. The burning of fossil fuels, deforestation, and other human activities all contribute to the greenhouse effect, increasing temperatures worldwide. 
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Other common causes of heatwaves are:

<ul>
	<li>Natural Variability - Both human and natural factors can cause heat waves. However, large-scale climate patterns, such as the El Ni&ntilde;o-Southern Oscillation (ENSO) can alter precipitation and temperature, and the atmospheric circulation patterns. Thus, affecting the frequency and severity of heatwaves.</li>
	<li>Urbanization - Concrete buildings, reduced greenery, and increased energy consumption commonly characterize urban cities. These factors contribute to the urban heat island effect, causing extreme temperatures in these areas. Furthermore, low-income cities are at a higher risk of heatwaves and their effects due to poverty and lack of resources.</li>
	<li>Deforestation - Trees not only provide shade but also play a role in cooling the air and reducing the amount of heat absorbed by the land. Thus, deforestation and the loss of green spaces worsen climate change and cause heat waves. 
	&nbsp;</li>
</ul>

Although South Asia is no stranger to hot weather before the monsoon season, the recent scorching temperatures and low rainfall have caused considerable damage across Pakistan. In the summer of 2022, an unprecedented heat wave led to the extreme Glacial Lake Outburst Flood in northern areas of the country. Furthermore, the melting of glaciers combined with unusual rains led to one of the worst floods in Pakistan&rsquo;s history in the last 30 years[9]. The devastating floods displaced millions across the country and caused an economic loss of more than US$ 30 billion<a href="#accordion">[9]</a>.

Heatwaves also increase the risk of wildfires. The 2022 heat waves led to forest fires in India and reduced the country&rsquo;s wheat crop yields, significantly affecting India&rsquo;s food supply. Furthermore, heatwaves contribute to the water crisis, reducing water availability for agriculture, drinking, etc. The habitat of various species is also affected, disrupting the ecosystems. 
&nbsp;

Exposure to extreme heat is associated with significant morbidity and mortality. It is the second major cause of weather-related deaths globally<a href="#accordion">[4]</a>. This is attributed to the high heat index, high humidity, and low winds increasing the risk of heat-related illnesses, such as heat strokes and heat exhaustion. In 2018, extreme heat exposure caused 296,000 deaths globally<a href="#accordion">[6]</a>. 
&nbsp;

Approximately 30% of Pakistan&rsquo;s population lives in absolute poverty<a href="#accordion">[4]</a>. These individuals have limited access to healthcare, water, cooling appliances, and adequate housing. Thus, they often have poorer health outcomes, especially during periods of extreme temperatures.

During heatwaves, the high heat index and humidity disrupt the body&rsquo;s evaporative cooling method of thermoregulation. As a result, the body is unable to cool down and heats up. Elevated body temperature is associated with severe heat-related illnesses, such as heat stroke. The elderly, children, those who work under the sun or go outside to earn an income (e.g., laborers, street vendors, farmers, and traffic policemen), and homeless people are most affected by extreme heat<a href="#accordion">[1]</a>. In this at-risk population, deaths and hospitalizations can occur quite rapidly.

Extreme heat can also worsen existing chronic conditions, such as diabetes and cardiovascular disease. Furthermore, heatwaves can also have indirect health effects. These include altered behavior, increased transmission of diseases, reduced air quality, and increased strain on energy, water, and transport<a href="#accordion">[10]</a>. 
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<h5>Agricultural Impact Of Heatwaves</h5>

High temperatures are associated with reduced growth and productivity of crops. Crop quality is further affected by the increased risk of pest outbreaks and disease. Water crises can also occur due to the increased water demand causing water scarcity. Moreover, heatwaves affect the soil moisture levels, which reduces nutrient uptake, further reducing crop yield.

As extreme heat can also increase the risk of wildfires, agricultural land, and livestock are ultimately damaged. Agricultural loss affects food security and the livelihoods of farmers and others in the agriculture sector. 
&nbsp;

<h5>Economical Impact Of Heatwaves</h5>

In 2019, extreme heat led to a global economic loss of 302 billion work hours[6]. The decreased productivity due to heat stress and illness among workers places a significant economic impact. Moreover, as people use cooling technologies such as air conditioning, the energy demand increases; thus, increasing energy costs.

Hence, existing water crises and air pollution problems are also often exacerbated. The increased strain on energy, water, and transportation causes power shortages and disrupts infrastructure.

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Solution

Although extreme heat is bound to cause losses, its implications are not inevitable. Various individual and community-level strategies can help mitigate the effects of heatwaves.

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Since urbanization is a major factor in the occurrence of heatwaves, increasing green spaces in urban areas has been shown to significantly improve air quality and reduce the risk of heat-related illnesses.

&nbsp;

Increasing access to clean water, healthcare, and adequate housing can help vulnerable communities deal with the effects of heatwaves. In rural areas, such measures can help reduce heat exposure. However, such measures are not always possible in low-income countries with limited resources. Therefore, in these cases, community-based awareness programs are effective at reducing heat-related morbidity and mortality.

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Public awareness campaigns, especially in rural areas and communities with limited resources, can help educate the public about heatwaves and measures to prevent heat-related illnesses. Healthcare workers and emergency service providers should also be trained in the effective treatment of heat illnesses. Thus, improving health outcomes for vulnerable populations. Furthermore, early warning systems for heatwaves can help at-risk communities prepare for heatwaves. 
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Conclusion

Unprecedented heatwaves place an increased burden on the city&rsquo;s health and emergency services. Moreover, they have significant health, economic and agricultural implications. However, awareness programs and early warning, and early action plans can help reduce morbidity and mortality associated with heatwaves.

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While the government has instilled in place action plans to combat the expected heatwaves, all these strategies are fruitless if policies that address the inevitable climate change are not implemented. Moreover, there is an urgent need to transition to renewable sources of energy to help mitigate the rising carbon emissions. 
&nbsp;

Key Points

<ul>
	<li>Low income countries are often plagued with limited resources, making them more vulnerable to the effects of climate change.</li>
	<li>Scientists define heat waves as prolonged periods of extremely high temperatures in a particular area. They can last for several days to weeks, and the temperatures in the area are way above the average for that location.</li>
	<li>The impact of heatwaves is generally higher in cities due to the urban heat island effect causing a 3.5 &deg;C&ndash;12&deg;C&thinsp;higher temperature than neighboring areas.</li>
	<li>During heatwaves, the high heat index and humidity disrupt the body&rsquo;s evaporative cooling method of thermoregulation. As a result, the body is unable to cool down and heats up.</li>
	<li>Extreme heat can also worsen existing chronic conditions, such as <a href="https://merisehat.pk/disease/diabetes-type-1-and-2">diabetes </a>and cardiovascular disease.</li>
	<li>Climate change and global warming are one of the major causes of heatwaves. The burning of fossil fuels, deforestation, and other human activities all contribute to the greenhouse effect, increasing temperatures worldwide.</li>
	<li>High temperatures are associated with reduced growth and productivity of crops. Crop quality is further affected by the increased risk of pest outbreaks and disease.</li>
	<li>&nbsp;The elderly, children, those who work under the sun or go outside to earn an income (e.g., laborers, street vendors, farmers, and traffic policemen), and homeless people are most affected by extreme heat.</li>
	<li>Agricultural loss affects food security and the livelihoods of farmers.</li>
	<li>Although extreme heat is bound to cause losses, its implications are not inevitable. Various individual and community-level strategies can help mitigate the effects of heatwaves.</li>
	<li>Increasing green spaces in urban areas has been shown to significantly improve air quality and reduce the risk of heat-related illnesses.</li>
	<li>Increasing access to clean water, healthcare, and adequate housing can help vulnerable communities deal with the effects of heatwaves. 
	&nbsp;</li>
</ul>

[1] Climate Change made devastating early heat in India and Pakistan 30 times more likely. World Weather Attribution.

[2] How Heat Waves Are Destabilizing Asia. United States Institute of Peace.

[3] Babar MS, Tazyeen S, Khan H, Tsagkaris C, Essar MY, Ahmad S. Impact of climate change on Health in Karachi, Pakistan. The Journal of Climate Change and Health. 2021;2:100013. doi:10.1016/j.joclim.2021.100013.

[4] Khan UR, Ahmed N, Naeem R, et al. Heat Emergencies: Perceptions and Practices of Community Members and Emergency Department Healthcare Providers in Karachi, Pakistan: A Qualitative Study. Int J Environ Res Public Health. 2021;18(9):4736. Published 2021 Apr 29.

[5] EXTREME WEATHER: SEARING HEAT WAVES AND TORRENTIAL RAINS IN PAKISTAN AND THEIR IMPACT ON HUMAN RIGHTS. Amnesty International Public Statement.

[6] Razzak JA, Agrawal P, Chand Z, Quraishy S, Ghaffar A, Hyder AA. Impact of community education on heat-related health outcomes and heat literacy among low-income communities in Karachi, Pakistan: a randomised controlled trial. BMJ Glob Health. 2022;7(1):e006845. doi:10.1136/bmjgh-2021-006845.

[7] Thiagarajan K. Heatwaves in India and Pakistan are lasting longer than previously seen. BMJ. 2022;377:o1143. Published 2022 May 5. doi:10.1136/bmj.o1143.

[8] Heatwaves. World Health Organization.

[9] Ishaque W, Tanvir R, Mukhtar M. Climate Change and Water Crises in Pakistan: Implications on Water Quality and Health Risks. J Environ Public Health. 2022;2022:5484561. Published 2022 Nov 22. doi:10.1155/2022/5484561.

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