Is Earth really getting too hot for people to survive? A scientist explains extreme heat and the role of climate change
My parents said the planet is getting too hot for people to live here. They called it climate change. What does that mean? – Joseph, age 12, Boise, Idaho
Many countries have seen extremely hot weather lately, but in most of the inhabited world, it's never going to get "," especially in relatively dry climates.
When it's hot outside in dry places, most of the time our by evaporating water and heat from our skin as sweat.
However, there are places where it , especially where hot deserts are right next to the warm ocean. When the air is humid, sweat doesn't evaporate as quickly, so sweating doesn't in drier environments.
In parts of the Middle East, Pakistan and India, summer that blows in off the sea, and this . Hundreds of millions of people live in those regions, most without access to indoor air conditioning.
Scientists like me use a "" to get a better sense of this risk. A wet bulb thermometer allows water to evaporate by blowing ambient air over a damp cloth. If the wet bulb temperature is over 95 F (35 C), and , the human body won't be able to let . Prolonged exposure to such combined heat and humidity can be fatal.
During a severe heat wave in 2023, wet bulb temperatures were , though they didn't reach fatal levels. In Delhi, India, where air temperatures (49 Celsius) for several days in May 2024, the wet bulb temperatures came close, and several from suspected in the hot and humid weather. In conditions like that, everyone has to take precautions.
Is it climate change?
When people - whether it's coal in a power plant or gasoline in a vehicle - it creates carbon dioxide (CO2). This invisible gas builds up in the atmosphere and traps the Sun's warmth near the Earth's surface.
The result is what we mean by "climate change."
Every bit of coal, oil or gas that ever gets burned . As temperatures rise, dangerously hot and humid weather has begun to spread to more places.
Areas of the U.S. Gulf Coast in Louisiana and Texas are increasingly in summer, as are heavily irrigated areas of the desert Southwest where water sprayed over farm fields adds moisture to the atmosphere.
Hot air evaporates a lot more water, so crops, forests and landscapes in some areas dry out, which makes them . Each Celsius degree of warming can cause a over parts of the western U.S.
Warming also , which can flood coastal regions. Rising sea levels threaten to displace as many as .
All of these impacts mean that climate change threatens the global economy. Continuing to burn coal, oil and gas could by the end of the century, according to one estimate.
Good news and bad news
There's both bad news and good news about climate change in the future.
The bad news is that as long as we keep burning carbon, it .
The good news is that we can , like solar and wind power, instead of burning carbon, to power the products and services of modern life.
There's been tremendous progress in the past 15 years in making , and almost every country on Earth has now before too much damage is done.
Just as our ancestors built better lives by switching from outhouses to indoor plumbing, we will avoid making our world unlivable by switching from coal, oil and gas to clean energy.
