Cities Most Vulnerable To Heat Stroke And Why

Heatwaves are the deadliest of all climate risks, and cities are especially prone to high temperatures due to the urban heat island effect. The number of cities exposed to extreme temperatures is expected to nearly triple by 2050, with over 1.6 billion people in nearly 1,000 cities facing regular heatwaves. This phenomenon is caused by a combination of population growth, climate change, and the urban heat island effect, which results in pavement and buildings radiating heat back into the air. Cities with little green space, such as those lacking parks or tree-lined streets, are particularly vulnerable to heat extremes, which can worsen air quality, cause dehydration, heat strokes, and even death. The social and economic disparities in access to cooling resources further exacerbate the impact of heatwaves, disproportionately affecting the poorest citizens and communities of colour.

The impact of blackouts during heatwaves

Blackouts during heatwaves can have devastating consequences for cities, and the risk of this combination is increasing. Power failures during heatwaves pose a severe threat to major cities, and new research highlights the potentially deadly impact of this growing problem.

The Rising Risk of Blackouts and Heatwaves

According to a study published in the journal Environmental Science & Technology, power failures have increased by over 60% in the United States since 2015, while climate change has intensified heatwaves. This trend is not limited to the US; by 2050, over 1.6 billion people in nearly 1,000 cities worldwide will face frequent extreme heatwaves if emissions are not urgently reduced.

The Impact on Human Health

The combination of blackouts and heatwaves can be deadly. A study by the Georgia Institute of Technology found that a concurrent blackout and heatwave would expose at least two-thirds of residents in three large US cities to heat exhaustion or heat stroke. The loss of power during a heatwave can more than double the rate of heat-related mortality, with vulnerable populations being the most at risk. The very young, the elderly, and people with pre-existing medical conditions are especially vulnerable to heat-related illnesses.

Overwhelming Emergency Services

Blackouts during heatwaves can also overwhelm emergency services and healthcare systems. In Phoenix, Arizona, a concurrent blackout and heatwave could result in more than 50% of the population requiring emergency medical care, far exceeding the capacity of regional emergency departments. During a 2016 heatwave in India, government hospitals received twice the number of patients as usual, and a record number were treated for heat-related illnesses.

Economic Impact

Service disruptions due to blackouts and heatwaves can have significant economic costs. Reduced labour productivity from high temperatures could decrease goods and service outputs by more than 20% in sectors like manufacturing and construction by 2050. Additionally, the economic cost of reduced productivity due to heat extremes is estimated to reach $2 trillion globally by 2030.

The Way Forward

To mitigate the impact of blackouts during heatwaves, cities need to enhance electrical grid resilience and implement urban heat management strategies. This includes increasing tree canopy cover, using high albedo roofing materials, and ensuring reliable public health services, such as uninterrupted electricity supplies and well-functioning sanitation systems.

The dangers of extreme heat

Extreme heat poses a grave threat to human health, and the situation is only getting worse as climate change intensifies. According to research, the number of cities exposed to extreme temperatures is expected to nearly triple by 2050, affecting over 1.6 billion people in nearly 1,000 cities. This issue is fuelled by global warming and is already causing death and destruction worldwide.

Health Risks

Extreme heat can lead to dehydration, heat exhaustion, and heat stroke. It can also cause flare-ups in chronic conditions such as migraines, arthritis, asthma, kidney disease, hypertension, type 2 diabetes, and cardiovascular disease. The risk of heat-related illnesses increases with age, and those with pre-existing medical conditions are especially vulnerable. Additionally, extreme heat can worsen mental health and increase the chances of work injuries, heart attacks, and infections.

Social and Economic Impacts

The impacts of extreme heat disproportionately affect low-income communities and communities of colour. These communities are more likely to reside in "heat islands," urban areas that are hotter due to the abundance of heat-absorbing roads and buildings and a lack of cooling green spaces. They may also have limited access to air conditioning, which can be a lifesaver during heat waves. The cost of cooling further disadvantages those on fixed incomes, who may struggle to afford the rising prices of maintaining a cool environment.

Power Failures

Power failures during heat waves pose an additional severe threat. Blackouts have increased by more than 60% since 2015 in the United States, and the combination of blackouts and extreme heat can be deadly. During heat waves, the demand for electricity surges as people rely on air conditioning and refrigeration to stay cool. This strain on the electrical grid can lead to power outages, leaving residents without access to cooling systems and further exacerbating the health risks associated with extreme heat.

Environmental Consequences

Extreme heat also has significant environmental consequences. It can worsen air quality, particularly in urban areas, creating a dangerous combination of severe heat and pollution. Additionally, the increasing demand for energy during heat waves can put energy supplies at risk, as seen in South Korea in 2013 when the government had to cut air-conditioning in public buildings to prevent a country-wide power shortage.

The importance of green spaces in cities

Green spaces in cities are vital for several reasons, and their importance will only increase as the world continues to urbanize. By 2050, it is estimated that 68% of the global population will live in cities, an increase of 2.5 billion people compared to today. This urbanization will lead to a near tripling of the number of cities exposed to extreme temperatures and, consequently, an increased risk of heat-related illnesses such as heat stroke.

The Urban Heat Island Effect

One of the primary benefits of green spaces in cities is their ability to mitigate the Urban Heat Island Effect (UHI). This phenomenon occurs when urban areas absorb and retain more heat than surrounding rural areas, leading to temperatures in cities being 3-4°C higher than in the countryside. The UHI effect is caused by several factors, including the absorption of sunlight by dark-colored surfaces, the physical properties of commonly used urban materials, and the concentration of human activity and energy consumption in cities.

The Cooling Effect of Green Spaces

Green spaces, such as parks, gardens, and trees, have a natural cooling effect. The vegetation in these spaces absorbs solar radiation and releases water vapor through transpiration, cooling the surrounding air and reducing temperatures by up to 5°C. This cooling effect is influenced by the size, shape, and density of the green space, as well as the diversity of plant species present.

Health Benefits

The presence of green spaces in cities has been linked to improved physical and mental health for residents. On the physical health side, research has shown that nature in urban areas can reduce air pollution, which is a major contributor to respiratory issues and other health problems. In addition, the cooling effect of green spaces can help reduce the risk of heat-related illnesses, such as heat stroke.

Mental health benefits are also associated with urban green spaces. Access to nature and green spaces has been shown to improve stress levels and concentration, while also reducing rates of depression and ADHD in children.

Social and Economic Benefits

Green spaces in cities offer social and economic benefits as well. They provide spaces for social interaction and community building, promoting a sense of belonging and connection within the city. Additionally, green spaces can drive economic development and increase property values in the surrounding areas, although this can lead to the gentrification of certain neighborhoods.

In conclusion, green spaces in cities are of utmost importance, especially as the world faces the growing threat of climate change and urbanization. These spaces offer a multitude of benefits, from mitigating the UHI effect and improving physical and mental health to driving social and economic development. As cities continue to expand and temperatures rise, incorporating and preserving green spaces will be crucial for building resilient and livable urban environments.

Strategies to protect vulnerable people

Heat stroke is a serious condition that can be deadly, and certain groups of people are more vulnerable to its effects. These include older people, particularly those living in homes without air conditioning or good airflow, and those with chronic illnesses or who are taking certain medications. People of any age who do not stay properly hydrated are also at risk, as are those who drink excessive alcohol.

To protect vulnerable people from heat stroke, several strategies can be implemented:

• Provide access to cooling centres: During heat waves, cities can open dedicated public cooling centres where people can go to escape the heat. These centres can be located in air-conditioned buildings such as shopping malls or libraries, and they can provide a place for people to cool off, even if just for a few hours.
• Encourage the use of cooling methods: Educate people on the importance of staying cool and hydrated during hot weather. This includes encouraging people to wear lightweight, loose-fitting clothing, use fans, and take cool showers or baths.
• Offer guidance on outdoor activities: Advise people to limit their time outdoors during the hottest parts of the day and to rest often in shady areas. Rescheduling or cancelling outdoor activities can also help reduce the risk of heat stroke.
• Promote proper hydration: Encourage people to drink plenty of fluids, even if they don't feel thirsty. Sports drinks can also help replace lost salts and minerals, but people with certain conditions, such as high blood pressure, should speak to their doctors before consuming them.
• Implement early warning systems: Developing early warning systems can help people plan and prepare for heat waves. For example, the Indian city of Ahmedabad has implemented a heat action plan that issues warnings seven days before a heatwave, allowing officials to plan their response.
• Improve urban infrastructure: The "urban heat island effect" can make cities several degrees warmer than their rural surroundings, increasing the risk of heat stroke. To mitigate this, cities can increase green spaces, plant trees, and replace hard surfaces with grass, green roofs, and urban wetlands to create a "sponge city" effect that helps keep temperatures cooler.
• Provide financial assistance: For those who cannot afford to buy or run air conditioners, financial assistance programs can help ensure access to cooling systems.
• Monitor at-risk individuals: Checking on vulnerable individuals, such as older adults, at least twice a day during heat waves can help identify any signs of heat exhaustion or heat stroke. This is especially important for those who live alone or may not have the resources to cool down their homes.

The role of urban planners in climate adaptation

Urban areas are significant contributors to climate change, and with the majority of the world's population residing in cities, the impacts of climate change are felt most acutely in these areas. Urban planners play a critical role in climate adaptation by implementing strategies to reduce the vulnerability of cities to climate risks and increase their resilience.

One of the key challenges urban planners face is addressing the Urban Heat Island (UHI) effect, where cities experience higher temperatures than their surrounding rural areas due to factors such as soil sealing

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