When Will Extreme Heat Become Unlivable?

Summary

As global temperatures rise due to climate change, extreme heat events are becoming more frequent and deadly. The video explores the difference between dry heat waves and humid heat, with a focus on dangerous wet-bulb temperatures, where the combination of heat and humidity makes cooling impossible. The risks of these events are highlighted, particularly for vulnerable populations. While air conditioning is crucial for survival, it also exacerbates climate change. The video emphasizes the need for clean energy solutions and urban design changes to mitigate the growing heat threat, offering a sobering look at the future and potential solutions.

Takeaways

• 😀 Dry heat waves have been the deadliest so far, but extreme humid heat waves (wet-bulb events) are rising as a greater concern due to climate change.
• 😀 Wet-bulb temperatures are a critical measure of heat and humidity combined, and they represent when conditions become deadly for humans.
• 😀 Wet-bulb temperature is a more dangerous and lethal threshold compared to regular temperature, with a 19°C wet-bulb being equivalent to extreme temperatures of 46°C in dry heat.
• 😀 Wet-bulb temperatures depend on factors like air temperature, humidity, activity level, and age. Older adults are at a greater risk due to less efficient thermoregulation.
• 😀 Studies show that at 2°C of global warming, a third of Earth's land area will likely experience dangerous wet-bulb temperatures, including highly populated regions in India, China, and the U.S.
• 😀 If global warming reaches 4°C, over 60% of Earth's landmass could experience these extreme wet-bulb temperatures, with more frequent and longer heat waves.
• 😀 Air conditioning is the primary means of surviving extreme heat, but it is costly, energy-intensive, and not universally accessible, especially in vulnerable areas.
• 😀 The increasing reliance on air conditioning can worsen climate change by contributing to higher carbon emissions, creating a feedback loop of rising temperatures.
• 😀 The power grid infrastructure is not designed to handle the widespread demand for air conditioning during heatwaves, leading to potential power outages that put vulnerable people at even greater risk.
• 😀 Beyond air conditioning, solutions include designing cities with cooler infrastructures like green roofs and more trees, improving electrical grid resilience, and prioritizing protection for the most vulnerable during heatwaves.
• 😀 The key takeaway is that while we are entering uncharted territory with climate change, there is still time to act and mitigate the severity of these changes through clean energy, better infrastructure, and preventive measures.

Q & A

What are the two types of heat waves discussed in the video?

The video discusses dry heat waves and humid heat waves. Dry heat waves are caused by high pressure systems trapping hot air, while humid heat waves, also called wet-bulb events, are characterized by both high heat and high humidity.

What is the wet-bulb temperature and why is it important?

The wet-bulb temperature combines heat and humidity into a single measurement. It's important because it indicates when conditions become dangerous or even lethal for humans. At higher wet-bulb temperatures, the body's ability to cool itself through sweating is impaired.

Why do wet-bulb events become more dangerous with climate change?

As global temperatures rise, more moisture can be held in the atmosphere, increasing humidity. This makes wet-bulb events more likely, and as they become more frequent, many of the most populated areas on Earth could experience dangerous wet-bulb temperatures.

What happened during the 2015 heat event in Karachi, Pakistan?

In 2015, Karachi experienced one of the most extreme humid heat events on record, with temperatures up to 45°C combined with high humidity. This led to widespread power outages and water shortages, causing at least 1,200 deaths, primarily from heatstroke and dehydration.

How does the human body regulate its temperature in high heat?

The human body primarily regulates its temperature by sweating. As sweat evaporates, it carries away heat, helping the body cool down. However, in high humidity, evaporation is less effective, making it harder for the body to cool itself.

What is the limit of compensability regarding wet-bulb temperature?

The limit of compensability is the point at which the human body can no longer effectively regulate its core temperature through sweating. Once this threshold is crossed, the body's temperature starts to rise uncontrollably, leading to dangerous health conditions.

At what wet-bulb temperature do scientists believe humans can no longer survive?

Wet-bulb temperatures that exceed about 32°C are considered dangerous, with limits of compensability ranging between 19°C to 32°C. This threshold varies based on factors such as age, activity level, and humidity.

What impact will two degrees Celsius of global warming have on wet-bulb thresholds?

At two degrees Celsius of global warming, about a third of Earth's land area is expected to experience dangerous wet-bulb temperatures. This will particularly affect densely populated regions such as parts of India, China, and the eastern U.S.

How do power grid failures impact people's safety during heat waves?

Power grid failures during heat waves can leave people without air conditioning, which is the primary way to stay cool in extreme heat. This puts vulnerable populations at greater risk, especially if the power outage is caused by weather events like hurricanes.

What are the limitations of air conditioning in mitigating extreme heat?

While air conditioning is essential for staying cool, it has limitations. It is expensive, energy-intensive, and not accessible to everyone, particularly in areas vulnerable to heat. Additionally, air conditioning contributes to the urban heat island effect, and widespread use can exacerbate climate change.