Heat Domes - UPSC

In January 2023, some European countries like Poland, Denmark, the Czech Republic, the Netherlands, Belarus, Lithuania, and Latvia saw their warmest weather ever, with temperatures soaring 10 to 20 degrees Celsius above normal. Experts explained that a heat dome had formed over the continent, creating this unusually hot period. It’s similar to what happened in 2021 when a heat dome caused extreme heat in western Canada and the US, leading to dangerous heatwaves. There was also another heat dome in the US in September 2022 that set new temperature records.

Must Read Blogs
Types Of Volcanic Mountains	Types Of Mountains
Tactical Nuclear Weapons	Evolution of Lithosphere
Sources Of Ocean Heat	Northern Europe: Landscape, Climate, Industry

What is a Heat Dome?

A heat dome happens when the air traps hot ocean air, acting like a lid on a pot.
Think of it as the atmosphere putting a cap on hot air coming from the ocean.
Heat domes are more likely during La Niña years, like 2021.
This is when the eastern Pacific is cool, and the western Pacific is warm.
It starts with a big change in ocean temperatures.
Warmer ocean surface causes air to rise, creating what’s called convection.
The temperature difference creates winds that push warm, tropical air eastward.
This warm air ends up trapped in the jet stream, a big current of air around the globe.
Eventually, this trapped warm air heads to the U.S. West Coast.
This journey contributes to the heatwaves we experience.
A heat wave is when we get unusually hot weather for more than two days.
It can affect a large area and expose many people to potentially dangerous heat.
Imagine the Pacific Ocean as a huge swimming pool with a heater.
Just like the pool warms up near the heater, the western Pacific has gotten warmer compared to the eastern Pacific in recent decades.

Impact of a Heat Dome

Loss of life: When heat domes strike, there’s a sudden spike in extreme heat, putting people without air conditioners at risk. This can lead to more unfortunate deaths.
Damage to crops: The intense heat from these domes isn’t just tough on us—it’s harsh on crops too. It dries out plants, damages them, and can even bring on droughts.
Rise in energy consumption: Heat waves don’t just make us sweat; they also make us use more electricity. This means higher energy bills for everyone as we crank up the air conditioning and fans to stay cool.
Increase in wildfires: Heat domes act like a firestarter for wildfires. The hot and dry conditions make it easier for fires to spread, causing significant damage to large areas of land in the US every year.
Cloud prevention: Strangely, heat domes don’t just make it hot—they also stop clouds from forming. This means more of the sun’s rays reach the ground, making things even hotter.

Causes of Formation of Heat Dome

Ocean Temperature Change:

Imagine the ocean as a giant pot of water. When parts of it get really hot and others stay cool, a sort of “stirring” happens.
This stirring, or convection, makes warm air above the hot parts rise. As it moves, it’s like a gust of warm wind heading towards the east.

Jet Stream and Heat Waves:

The wind carries this warm air towards land, but something interesting happens in the sky. The jet stream, like a big air current, kind of traps this warm air and pushes it down to the ground.
When this warm air reaches the land, it causes heat waves – those scorching days that feel like the sun is extra strong.

Atmospheric Pressure Shift:

Now, let’s talk about air pressure. Imagine the atmosphere like a cozy blanket. When a high-pressure system (like a weighty hand) comes in, it pushes warm air down even more.
This makes things change course in the sky, and suddenly, there’s less wind and fewer clouds. The air feels thick and hot, making it a perfect recipe for a heat wave.

Climate Change Twist:

We know that sometimes it gets really hot on land, but lately, it’s been getting even hotter and sticking around longer. That’s because of something called climate change.
The Earth is warming up, and scientists are pretty sure it’s because of things people are doing. So, when you feel those intense heat waves, it’s like a signal that we need to be kinder to our planet.