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My parents said the planet is getting too hot for humans to live here. They called it climate change. What does that mean? – Joseph, age 12, Boise, Idaho
Many countries have seen very hot weather recently, but in most of the inhabited world, it will never get “too hot to live here,” especially in fairly dry climates.
When it’s hot outside in dry places, most of the time our bodies can cool down by evaporating water and heat from our skin as sweat.
However, there are places where it gets dangerously hot and humid from time to time, especially where there are hot deserts right next to the hot ocean. When the air is humid, sweat doesn’t evaporate as quickly, so sweating doesn’t cool us down like it does in drier environments.
In parts of the Middle East, Pakistan and India, summer heat waves can combine with moist air blowing in from the sea, and this combination can be downright deadly. Hundreds of millions of people live in those regions, most without access to indoor air conditioning.
Scientists like me use a “wet bulb thermometer” to better understand this risk. A wet bulb thermometer allows water to evaporate by blowing ambient air over a damp cloth. If the wet bulb temperature is above 95 F (35 C), and even at lower levels, the human body will not be able to release enough heat. Prolonged exposure to such combined heat and humidity can be fatal.
During a severe heat wave in 2023, very high wet bulb temperatures across the Mississippi Valley were lower, although they did not reach lethal levels. In Delhi, India, where the air temperature exceeded 120 degrees Fahrenheit (49 Celsius) for several days in May 2024, wet bulb temperatures approached, and several people died of suspected heat stroke in the hot weather and moist. In such conditions, everyone must take precautions.
Is it climate change?
When people burn carbon – whether it’s coal in a power station or gasoline in a vehicle – it creates carbon dioxide (CO2). This invisible gas rises in the atmosphere and absorbs the sun’s heat near the Earth’s surface.
What we mean by “climate change” is the result.
Every bit of coal, oil or gas ever burned adds a little more to the temperature. As temperatures rise, dangerously hot and humid weather has begun to spread to more places.
Areas of the US Gulf Coast in Louisiana and Texas are increasingly at risk of dangerously hot and humid summer conditions, as are areas of the heavily irrigated desert Southwest where water sprayed over farm fields adds moisture to the atmosphere.
Climate change causes far more problems than hot sweaty weather.
Warm air evaporates much more water, so crops, forests and landscapes dry out in some areas, making them more susceptible to wildfires. Each degree Celsius of warming can cause a six-fold increase in wildfires across parts of the western US
Warming also causes ocean water to expand, which can flood coastal regions. Rising sea levels threaten to displace up to 2 billion people by 2100.
All these impacts mean that climate change is a threat to the global economy. Global income could be cut by around 25% by the end of the century, according to one estimate, if coal, oil and gas continue to be burned.
Good news and bad news
There is bad news and good news about future climate change.
The bad news is that as long as we keep burning carbon, it will get hotter and hotter.
The good news is that we can replace burning carbon with clean energy, such as solar and wind power, to power the products and services of modern life.
Great progress has been made in the last 15 years in making clean energy reliable and affordable, and almost every country in the world has now agreed to stop climate change before too much damage is done.
Just as our ancestors developed better lives by switching from outdoor homes to indoor plumbing, our world will inevitably be avoided by switching from coal, oil and gas to clean energy.
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This article is republished from The Conversation, a non-profit, independent news organization that brings you reliable facts and analysis to help you make sense of our complex world. It was written by Scott Denning, Colorado State University
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Scott Denning has received funding from the National Science Foundation.
