Ever felt like you’re living in an oven? That’s a heatwave! These scorching stretches of super hot weather aren’t just uncomfortable, they can be dangerous too. But why do they happen?

 

• Imagine the sun like a giant lamp and Earth like a giant rock. Normally, some of the sun’s heat bounces back into space, keeping things balanced. But sometimes:

 

Big Air Blanket: A big area of high pressure acts like a giant blanket, trapping the sun’s heat close to Earth. Think of a closed car on a hot day – it gets super hot inside!

 

But why high pressure develop?

 

High-pressure systems, which contribute to heatwaves, form due to the circulation of air in the atmosphere. Here’s a simplified explanation:

 

Air Movement: Imagine air as a giant invisible blanket surrounding Earth. This blanket isn’t evenly distributed – some areas have more air molecules (denser) than others (less dense). Air naturally moves from denser areas (high pressure) to less dense areas (low pressure).

Sun’s Heat: The sun’s heat warms the Earth’s surface unevenly. Areas near the equator receive more direct sunlight, causing the air there to become warm and rise.

Sinking Air: As warm air rises, it cools and expands, eventually reaching a certain height where it starts to sink back down towards the Earth’s surface. This creates a large, high-pressure zone where the air is sinking and compressing (think of squeezing a stress ball – it gets denser).

Where Heatwaves Happen: These high-pressure systems can settle over a particular region for extended periods. This sinking air gets further warmed by compression, leading to the clear skies, stagnant air, and rising temperatures associated with heatwaves.

 

How it leading to the clear skies, stagnant air, and rising temperatures associated with heatwaves?

 

• Imagine a greenhouse. The glass walls allow sunlight to enter and heat the interior, but they trap the heat inside. Similarly, in a high-pressure system, the clear skies act like the glass walls, allowing sunlight to heat the Earth’s surface, and the stagnant air acts like a barrier, preventing the heat from escaping, resulting in rising temperatures.

 

Remember, this is a simplified explanation: Air circulation patterns in the atmosphere are complex, influenced by Earth’s rotation and other factors. However, the basic idea is that areas under persistent high-pressure systems experience the conditions that contribute to heatwaves.

 

Missing Cloud Cover: Clouds act like an umbrella, blocking some of the sun’s rays. But if there aren’t many clouds, the sun’s heat hits the Earth directly, making it hotter.

Our Warming World: Earth’s temperature is slowly rising, kind of like a pre-heated oven. This makes it easier for heatwaves to develop and become more intense.

City Heat Islands: Cities with lots of buildings and pavement soak up and trap heat, making them even hotter than surrounding areas. Imagine wearing a black shirt on a hot day – that’s what a city feels like!

 

So, The Culprits Behind the Heat:

 

Heatwaves are the result of a complex interplay between natural and human-induced factors. Here’s a breakdown of the key causes:

 

• • High Pressure Systems: When high-pressure systems settle over a region, they trap warm air near the Earth’s surface, leading to rising temperatures and stagnant air. These systems often persist for extended periods, intensifying the heatwave’s duration and severity.
• • Reduced Cloud Cover: Clouds act like a natural sunscreen, blocking some of the sun’s rays from reaching Earth. A lack of cloud cover due to weather patterns or atmospheric changes allows for more solar radiation to reach the ground, accelerating heat buildup.
• • Global Warming: The long-term increase in Earth’s average temperature, primarily driven by greenhouse gas emissions like carbon dioxide, plays a significant role in heatwaves. A warmer baseline temperature makes it easier for heatwaves to develop and become more intense.
• • Urban Heat Island Effect: Urban areas typically experience higher temperatures than surrounding rural areas. This phenomenon, known as the urban heat island effect, arises due to several factors – increased absorption and retention of heat by buildings and pavement, reduced greenery, and waste heat generated by human activities.

 

What is Heat Dome and how it is linked with heatwave?

 

A heat dome can be considered a specific atmospheric condition that can contribute to a more intense heatwave. Here’s how they’re connected:

 

• • Heatwaves: As explained earlier, heatwaves occur due to high-pressure systems trapping warm air near the Earth’s surface, leading to clear skies, stagnant air, and rising temperatures.
• • Heat Domes: A heat dome is a specific type of high-pressure system where the upper atmosphere acts like a “lid,” preventing hot air near the surface from escaping. This trapped hot air intensifies and persists for longer durations, leading to extreme heat events.

 

Here’s an analogy: Imagine a pot on a stove with a lid. A regular heatwave is like turning up the heat under the pot. The pot gets hot, but some heat escapes. Now, imagine putting a tight lid on the pot. That’s a heat dome – the trapped heat intensifies and stays longer, making the pot (Earth’s surface) much hotter.

 

Key Points:

 

• • Not all heatwaves are caused by heat domes, but heat domes can significantly worsen a heatwave.
  • Heat domes are often associated with specific weather patterns like La Niña.
  • Both heatwaves and heat domes can be exacerbated by climate change as rising global temperatures make these extreme weather events more likely and intense.

 

Heatwaves can cause big problems, like:

 

• • Dryness: Hot weather sucks up moisture, leading to droughts and wildfires.
  • Dirty Air: Heat traps pollution, making it harder to breathe.
  • Sick People: Heat can be dangerous, especially for older folks and young kids.

 

So, what can we do?

 

• • Be Cool: Stay hydrated, wear loose clothes, and avoid strenuous activity during heatwaves.
  • Plant Trees: More trees create shade and cool down cities.
  • Save Energy: Using less energy helps reduce greenhouse gases that trap heat.
  • Clean Up Our Act: Reducing pollution helps keep the air cleaner, even during heatwaves.
  • By understanding heatwaves and taking action, we can stay cool and healthy in a warming world!

 

• • 

Mains Questions:

 

Model Answer:

 

Factors Contributing to Heatwaves:

• • High-pressure systems: Sinking air in these systems gets compressed and warms up, leading to clear skies and stagnant air, trapping heat near the surface.
  • Reduced cloud cover: Lack of clouds allows more solar radiation to reach Earth, accelerating heat buildup.
  • Global warming: Rising average temperatures due to greenhouse gas emissions make it easier for heatwaves to develop and become more intense.
  • Urban heat island effect: Cities absorb and retain more heat compared to rural areas due to buildings and pavement, exacerbating heatwaves.

Consequences of Heatwaves:

• • Human Health: Heatstroke, heat exhaustion, heat-related illnesses, especially for vulnerable populations like the elderly and children.
  • Environment: Droughts, wildfires, air quality degradation due to trapped pollutants, and disruption of ecosystems.

Mitigation Strategies:

• • Reducing Greenhouse Gas Emissions: Transitioning to renewable energy and sustainable practices can slow global warming and lessen heatwave intensity.
  • Urban Planning: Greening cities, promoting cool roof surfaces, and investing in heat-resistant infrastructure can reduce the urban heat island effect.
  • Early Warning Systems: Implementing robust heatwave warning systems and public education campaigns can help individuals take precautions and minimize health risks.
  • Water Conservation: Promoting water-saving practices and sustainable water management are crucial during droughts intensified by heatwaves.

 

 

Model Answer:

 

Impact of Heatwaves on Different Sectors:

• • Agriculture: Droughts and extreme heat stress crops, impacting yields and food security.
  • Energy Demand: Increased use of air conditioning raises energy demand, putting a strain on power grids.
  • Infrastructure: Heat can damage roads, bridges, and other infrastructure, leading to costly repairs and disruptions.

Adaptation Strategies:

• • Agriculture: Developing heat-resistant crop varieties, adopting water-efficient irrigation practices, and promoting climate-smart agriculture.
  • Energy: Investing in renewable energy sources to meet peak demand, promoting energy-efficient buildings and appliances.
  • Infrastructure: Using heat-resistant materials for construction, creating green spaces for shade and temperature regulation, and upgrading power grids to handle increased demand.

Building Resilience:

• • Investing in research and development of heat-resistant technologies and early warning systems.
  • Implementing heat action plans to coordinate responses across different sectors during heatwaves.
  • Raising public awareness about heatwave risks and promoting individual preparedness measures.
  • By adopting these mitigation and adaptation strategies, we can build resilience and reduce the negative impacts of heatwaves on various sectors and society as a whole.

 

Remember: These are just sample answers. It’s important to further research and refine your responses based on your own understanding and perspective. Read entire UPSC Current Affairs.