Urban Heat Management: Crisis and Solutions | DTE Call For Action

Summary

In 2023 and 2024, India faced unprecedented heatwaves, with Delhi experiencing a 39-day spell above 40°C. The India Meteorological Department reported a 62% rise in heatwave-related deaths over 20 years. The crisis is exacerbated by declining green spaces and increasing urban heat islands. Solutions include enhancing urban planning with green infrastructure, integrating passive cooling in structures, and adopting sustainable technologies to reduce heat impacts.

Takeaways

• 🌡️ India experienced record-breaking heatwaves in 2023 and 2024, with severe impacts on health and infrastructure.
• 🏙️ Delhi faced a particularly harsh 39-day heat spell, highlighting the widespread nature of the heat crisis.
• ⚠️ There's been a significant increase in heatwave-related deaths, with a 62% rise over the past 20 years.
• 🌡️ Heat exposure is severe, affecting over 90% of the area in several Indian cities during peak summer months.
• 💧 Humidity, when excessive, can worsen heat conditions, contributing to the heat index and increasing health risks.
• 🌳 The decline in green and blue infrastructure is a significant factor behind the heat crisis, as it leads to urban heat islands.
• 🏢 Urban planning flaws, such as high-rise buildings and heat-retaining materials, exacerbate the urban heat island effect.
• 🌡️ Night-time temperatures are a concern, with the risk of mortality being higher on hot days with hot nights.
• 🌿 A 'Recipe of Coolth' is proposed, focusing on urban planning, structures, and metabolism to combat the heat crisis.
• 🔄 Renewable energy sources and efficient cooling technologies are key to reducing heat impacts and creating livable urban spaces.

Q & A

What was the record-breaking heat event in Delhi during 2023 and 2024?

Delhi experienced a record-breaking 39-day heat spell from May 13th to June 20th, with temperatures consistently exceeding 40 degrees.

How has the frequency and severity of heatwaves in India changed over the past 20 years according to the India Meteorological Department and the Ministry of Earth Sciences?

There has been a 62% increase in heatwave-related deaths over the past 20 years, driven by a 138% rise in heatwaves.

Which Indian cities were particularly affected by extreme heat according to the CSE analysis?

Nagpur and Ahmedabad were particularly affected, with over 95% of their areas exposed to high heat.

What is the heat index and how does it affect our perception of heat?

The heat index tells us how hot it feels when we combine the air temperature with the humidity, indicating that it's not just hot, it's 'sticky hot'.

What is the impact of declining green and blue infrastructure on urban heat?

Declining green and blue infrastructure leads to a rise in heat-retaining materials like concrete and asphalt, which trap heat and contribute to the urban heat island effect.

How does the Urban Heat Island effect influence mortality rates?

The risk of mortality is 50 percent higher on hot days with hot nights compared to hot days with cooler nights.

What role does urban planning play in exacerbating the heat effect in cities?

Unthoughtful urban planning can hinder natural wind flow, resulting in stagnant air and reduced ventilation, which intensifies heat accumulation.

How can the use of air conditioners contribute to the heat issue in cities?

The reliance on air conditioners not only boosts greenhouse gas emissions but also releases additional heat outdoors, further intensifying the heat issue.

What is the 'Recipe of Coolth' mentioned in the script and what does it involve?

The 'Recipe of Coolth' involves working on various elements at three levels: urban cover, structures, and metabolism, to combat the heat crisis through comprehensive urban planning, passive cooling elements, and efficient utilization of cooling technologies.

How can cities adapt to mitigate the impact of heatwaves?

Cities can adapt by enhancing and expanding blue-green infrastructure, incorporating passive cooling elements in urban structures, and focusing on urban design with sustainable building materials and nature-based cooling measures.

What is the relationship between air pollution and heat as mentioned in the script?

Areas with high pollution levels often experience higher temperatures due to pollutants trapping heat near the ground.

Outlines

00:00

🌡️ Record-Breaking Heatwaves in India

India experienced unprecedented heatwaves in 2023 and 2024, particularly in Delhi where a 39-day spell with temperatures consistently over 40 degrees Celsius turned the city into a furnace. The India Meteorological Department reported a 62% increase in heatwave-related deaths over the past two decades, with Delhi alone recording 270 deaths by mid-2024. The script raises questions about the adequacy of adaptive measures and infrastructure to combat these extreme conditions. It also discusses the heat exposure in nine Indian cities, revealing that over 90% of the geographic area in seven cities faced extreme heat during peak summer months. The heat index, which combines air temperature and humidity, is highlighted as a key factor in understanding the risk levels of heat-related illnesses. The script points out the decline in green and blue infrastructure and the rise of heat-retaining materials like concrete and asphalt, leading to urban heat islands where city centers are significantly hotter than rural areas.

05:05

🌿 Crafting a 'Recipe of Coolth' for Urban Resilience

The script outlines a comprehensive approach to combat the heat crisis, focusing on urban planning, structures, and metabolism. It suggests enhancing blue-green infrastructure to improve air quality and reduce heat. For urban structures, it recommends passive cooling elements like chajjas and green roofs, and emphasizes the need for sustainable building materials and designs that provide thermal comfort. In terms of urban metabolism, it proposes efficient utilization of cooling technologies and renewable energy sources to offset anthropogenic heat. The script concludes by emphasizing the need for cities to adapt and innovate to create resilient and livable spaces in the face of changing climate conditions, framing the fight against heatwaves as a fight for our future.

Keywords

💡Heatwaves

Heatwaves refer to prolonged periods of excessively hot weather, which can have severe impacts on human health and the environment. In the context of the video, heatwaves are a central theme, as they have been increasing in severity and frequency in India, causing record-breaking temperatures and strain on the health system. The script mentions a 39-day heat spell in Delhi, highlighting the extreme conditions faced by the city.

💡Heat index

The heat index is a measure that combines air temperature and humidity to indicate how hot it feels to the human body. It is crucial for understanding the discomfort and potential health risks associated with high temperatures. The video script uses the heat index to explain how the combination of heat and humidity exacerbates the effects of heatwaves, making them feel even more intense.

💡Urban heat islands

Urban heat islands are areas within cities that are significantly warmer than their surrounding rural areas due to human activities and the materials used in urban construction. The script discusses how the use of heat-retaining materials like concrete and asphalt in urban areas contributes to the creation of urban heat islands, which trap heat and lead to higher temperatures, especially in city centers.

💡Green and blue infrastructure

Green and blue infrastructure refers to natural and semi-natural areas, such as parks, trees, and water bodies, that provide environmental benefits, including cooling effects in urban areas. The video script highlights the decline of such infrastructure in Indian cities, which has contributed to increased heat exposure and the exacerbation of heatwaves.

💡Passive cooling

Passive cooling involves architectural and urban design strategies that reduce the need for mechanical cooling by utilizing natural processes such as shade, ventilation, and thermal mass. The script suggests incorporating passive cooling elements like chajjas (awnings) and green roofs to mitigate the heat island effect and reduce reliance on air conditioning.

💡Climate action

Climate action encompasses the steps taken to mitigate the effects of climate change and adapt to its impacts. In the video, climate action is linked to urban planning that integrates strategies to reduce heat exposure and improve resilience to heatwaves, such as enhancing green spaces and using sustainable building materials.

💡Heat stress

Heat stress occurs when the body is unable to cool itself adequately in response to extreme heat, which can lead to serious health problems. The video script mentions that several Indian cities face recurrent heat stress, indicating prolonged periods of heat exposure that can have severe consequences for residents.

💡Air pollution

Air pollution refers to the presence of harmful substances in the air, which can have negative effects on human health and the environment. The script connects air pollution with heat, noting that areas with high pollution levels often experience higher temperatures due to pollutants trapping heat near the ground.

💡Renewable energy

Renewable energy sources, such as solar thermal, solar PV, and biomass, are highlighted in the video as a means to offset anthropogenic heat and reduce greenhouse gas emissions. The script suggests increasing the reliance on renewable energy as part of the strategy to combat the heatwave crisis.

💡Sustainable urban planning

Sustainable urban planning is an approach to city development that considers environmental, social, and economic factors to create livable, resilient, and resource-efficient urban spaces. The video emphasizes the need for comprehensive urban planning that includes climate action and focuses on enhancing green-blue infrastructure to mitigate the effects of heatwaves.

💡Resilience

Resilience in the context of the video refers to the ability of urban environments to withstand, adapt, and recover from the impacts of climate change, particularly heatwaves. The script discusses strategies to build urban resilience, such as improving green and blue infrastructure and incorporating passive cooling elements in urban design.

Highlights

India experienced record-breaking heat in 2023 and 2024, straining its health system.

Early and severe heatwaves arrived in several Indian cities, increasing in frequency.

Delhi faced a 39-day heat spell from May 13th to June 20th, with temperatures consistently over 40 degrees.

Heatwave-related deaths increased by 62% over the past 20 years, with a 138% rise in heatwaves.

Delhi recorded 270 heatwave-related deaths by mid-2024.

Over 90% of the geographic area in seven Indian cities experienced extreme heat during peak summer months.

Nagpur and Ahmedabad were particularly affected, with over 95% of their areas exposed to high heat.

The heat index, combining air temperature and humidity, indicates how hot it feels.

The current rate of Earth's temperature increase is unprecedented, pointing to significant human contributions.

Declining green and blue infrastructure, such as parks and water bodies, is a significant factor behind the heat crisis.

Urban heat islands are created by heat-retaining materials like concrete and asphalt, trapping heat.

Night-time temperatures are concerning, offering no respite from the day's heat.

High-rise buildings and poor urban planning exacerbate the heat effect.

Uncovered surfaces like parking lots and metal roofs contribute to the urban heat island effect.

Reliance on air conditioners boosts greenhouse gas emissions and releases additional heat outdoors.

Air pollution and heat are closely linked, with high pollution levels often experiencing higher temperatures.

A 'Recipe of Coolth' involves working on urban cover, structures, and metabolism to combat the heat crisis.

Urban planning must integrate climate action, focusing on enhancing blue-green infrastructure.

Passive cooling elements and sustainable building materials can reduce reliance on mechanical cooling systems.

Efficient utilization of technologies and renewable energy sources can reduce heat impacts.

Cities must adapt and innovate to mitigate heat and create resilient, livable urban spaces.

Transcripts

In 2023 and 2024, India witnessed record-breaking  heat, with its health system feeling the strain.  

Several Indian cities witnessed early arrival of  heatwaves, with increased severity and frequency. 

For instance, a record-breaking  39-day heat spell from May 13th  

to June 20th in Delhi turned the city into a  virtual furnace, with temperatures consistently  

exceeding 40 degrees. These conditions were  not just confined to Delhi; several Indian  

cities faced similar harsh conditions, forcing  citizens to confront the dire consequences. 

The India Meteorological Department and  the Ministry of Earth Sciences reports a  

62% increase in heatwave-related deaths over the  past 20 years, driven by a 138% rise in heatwaves.  

Delhi alone recorded 270 deaths by mid-2024. Can we actually reverse the devastation of  

these extreme heatwaves? Do we have adequate  adaptive measures and infrastructure in place?  

Stay with us as we explore these crucial issues  and uncover what’s at stake for our future.

Let us first understand how  exposed we are to the heat. 

To grasp the full extent of heat exposure, let’s  delve into some revealing findings. CSE examined  

heat patterns in nine Indian cities—Pune,  Kolkata, Chennai, Bhubaneswar, Delhi, Nagpur,  

Jaipur, Ahmedabad, and Hyderabad—over a decade. The analysis showed that during peak summer  

months, over 90 % of the geographic area in seven  cities experienced extreme heat. Additionally,  

five cities had around 80 % or more of  their regions facing recurrent heat stress,  

indicating that residents endured prolonged  heat exposure. Nagpur and Ahmedabad were  

particularly affected, with over 95 %  of their areas exposed to high heat.

Humidity can offer some relief, but once it  crosses a threshold, it worsens the heat. These  

extreme conditions are becoming more frequent and  are extending into previously pleasant seasons,  

exacerbating the discomfort. That’s  because of something called the heat index. 

The heat index tells us how  hot it feels when we combine  

the air temperature with the humidity.  Think of it as Nature's way of saying,  

'It's not just hot, it’s sticky hot!' This chart helps us understand the risk  

levels of heat-related illnesses. The higher the  heat index, the more precautions we must take.

While Earth's temperature naturally fluctuates  over time, the current rate of increase is  

unprecedented, pointing to significant  human contributions to excessive heat. 

A significant factor behind this crisis is  declining green and blue infrastructure—like  

parks, trees, and water bodies. Not  just in one, two or three cities,  

the analysis reveals a troubling trend: with  all the nine cities revealing a decline. 

In their place, heat-retaining materials  like concrete and asphalt have come up,  

trapping heat and making cities extremely hot.  This trapped heat bounces from one surface to  

another, creating hotspots and developing  a phenomenon of urban heat islands, where  

temperatures in city centers are significantly  higher than in surrounding rural areas. 

Regardless of climate or geography, the  materials used for constructions usually  

have a heat-retaining property,  absorbing heat during the day and  

gradually releasing it at night, keeping  temperatures elevated around the clock. 

Night-time temperatures are particularly  concerning, offering no respite from the day's  

heat. The Urban Heat Island effect is especially  pronounced at night. An analysis shows that the  

risk of mortality is 50 percent higher on hot  days with hot nights compared to hot days with  

cooler nights. However, if the impact of  climate change is mitigated, this risk  

of having warmer nights, with temperatures  exceeding 25 °C, could be reduced by 32 %.

In our expanding cities, high-rise buildings,  

especially those beyond the cooling influence  of green or blue infrastructure, exacerbate  

the heat effect. For example, while both  a low-rise and high-rise building might  

have shaded lower floors, the high-rise's upper  floors would be exposed to more direct sunlight,  

which increases the heat gains. Unthoughtful urban planning typically  

hinders natural wind flow, resulting in stagnant  air and reduced ventilation that intensifies heat  

accumulation, leading to higher temperatures. Surfaces directly exposed to heat, such as  

uncovered parking lots, barren/open lands, and  metal roofs, significantly contribute to heat.  

These surfaces absorb and radiate heat, turning  them and their surroundings into heat sinks,  

which exacerbates the urban heat island effect. All of these factors—concretization,  

high fabric density, unplanned layouts,  and exposed surfaces—often lead to a heavy  

reliance on air conditioners. This creates a  dual problem: it not only boosts greenhouse  

gas emissions but also releases additional heat  outdoors, further intensifying the heat issue.

Moreover, air pollution and heat are closely  linked. Areas with high pollution levels  

often experience higher temperatures due to  pollutants trapping heat near the ground. 

But all is not lost. We can craft a 'Recipe  of Coolth' to combat this crisis. We have to  

work on various elements at three levels:  urban cover, structures, and metabolism. 

At the urban cover level, a comprehensive  approach to urban planning is crucial. Master  

plans must integrate climate action, focusing on  enhancing and expanding blue-green infrastructure,  

which offers benefits like improved  air quality and heat reduction. 

In urban structures, we need to incorporate  passive cooling elements like chajjas,  

awnings, and vertical greens. Additionally,  rooftops should be upgraded with cool roofs,  

green roofs, or covered with reflective  paints. Moreover, a critical focus  

on urban design is essential, with building  codes incorporating compact designs,  

optimizing urban morphology, streetscaping,  and utilizing nature-based cooling measures. 

We must think ‘Beyond Concrete’, integrating  sustainable and climate-specific building  

materials and designs that offer  thermal comfort, thus reducing  

reliance on mechanical cooling systems. In terms of urban metabolism, agglomerating  

cooling demands for the efficient utilization of  technologies like not-in-kind cooling systems,  

which release comparatively less heat into the  environment, can further reduce heat impacts. 

Additionally, offsetting anthropogenic heat  through higher penetration of renewable energy  

sources – such as solar thermal, solar PV and  biomass and increasing reliance on technological  

interventions that supports efficient cooling  could significantly reduce the temperatures. 

As the heatwave continues its grip, it's clear  our cities must adapt and innovate. The challenge  

is immense, but with the right strategies, we can  mitigate the heat and create urban spaces that are  

resilient and livable in a changing climate. The  fight against heatwave is a fight for our future.”