Urban Heat Management: Crisis and Solutions | DTE Call For Action
Summary
TLDRIn 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
🌡️ 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.
🌿 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.
Mindmap
Keywords
💡Heatwaves
💡Heat index
💡Urban heat islands
💡Green and blue infrastructure
💡Passive cooling
💡Climate action
💡Heat stress
💡Air pollution
💡Renewable energy
💡Sustainable urban planning
💡Resilience
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.”
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