Less than a month into the summer of 2024, the vast majority of the U.S. population has already experienced an extreme heat wave. Millions of people were under heat warnings in the western U.S. in early July or sweating through the humid heat in the east.
On July 7, Death Valley reached a dangerous 129 degrees Fahrenheit (53.9 C), a day after a motorcyclist died there from heat exposure. Las Vegas broke his all-time heat record at 120 F (48.9 C). In California, days of temperatures above 100 degrees dried out the landscape across much of the state, sparking wildfires. Oregon reported multiple suspected heat-related deaths.
In 2024, countries around the world will be hit by extreme heat.
Globally, each of the past 13 months has been the warmest on record for that month, including the warmest June, according to the European Union’s Copernicus climate service. The service reported on July 8, 2024, that the average temperature for the previous 12 months was also at least 1.5 C (2.7 F) warmer than the pre-industrial average of 1850-1900.
The 1.5C warming threshold can be confusing, so let’s take a closer look at what it means. Under the Paris Climate Agreement, countries worldwide agreed to work to limit global warming to below 1.5C, but that refers to the average temperature change over a 30-year period. A 30-year average is used to minimize the impact of natural fluctuations from year to year.
So far, the Earth has only exceeded that threshold for one year. However, it is still extremely worrying and the world appears to be on track to exceed the 1.5 C threshold in 30 years.
We study weather patterns related to heat. Early season heat, part of a warming trend fueled by humans, is endangering lives around the world.
Heat is becoming a global problem
In 2024, several countries in North and South America, Africa, Europe and Asia were hit by record heat. In Mexico and Central America, weeks of persistent heat from the spring of 2024 combined with prolonged drought led to severe water shortages and dozens of deaths.
Extreme heat turned into tragedy in Saudi Arabia, when more than 1,000 people on the Hajj, an Islamic pilgrimage to Mecca, collapsed and died. Temperatures reached 125 F (51.8 C) inside the Grand Mosque in Mecca on June 17.
Hospitals in Karachi, Pakistan, were overwhelmed by weeks of extreme heat, frequent power outages and water shortages in some areas. Neighboring India experienced temperatures of around 120 degrees Fahrenheit (48.9 degrees Celsius) for several days in April and May, affecting millions of people, many of whom lacked air conditioning.
In Greece, where temperatures in June soared above 37.8 degrees Celsius for days, several tourists have died or were feared dead after going hiking in the dangerous heat and humidity.
Japan has issued heat stroke warnings in Tokyo and more than half of Japan’s prefectures as temperatures hit record highs in early July.
The Climate Connection: This Isn’t ‘Just Summer’
While heatwaves are a natural part of the climate, the severity and magnitude of heatwaves so far in 2024 are not “summer only”.
A scientific assessment of the June 2024 Eastern U.S. heat wave estimates that heat this severe and prolonged would be two to four times more likely to occur today due to human-caused climate change than it would have been without it. This conclusion is consistent with the rapid increase in the number of heat waves in the U.S. in recent decades and their occurrence outside the peak of summer.
These record heat waves are occurring in a climate that is more than 2.2 F (1.2 C) warmer globally — based on the 30-year average — than it was before the Industrial Revolution, when humans began emitting vast amounts of climate-warming greenhouse gases.
While a temperature difference of a degree or two may not be noticeable when you walk into another room, even fractions of a degree can make a big difference in the global climate.
At the height of the last ice age, about 20,000 years ago, when the northeastern U.S. was under thousands of feet of ice, the global average temperature was only about 11 F (6 C) cooler than it is today. So it’s not surprising that 2.2 F (1.2 C) of warming so far would quickly change the climate.
If you thought this was hot
While this summer is likely to be one of the warmest on record, it’s important to realize that it could also be one of the coldest summers in the future.
For populations that are especially vulnerable to heat, including young children, the elderly, and outdoor workers, the risks are even greater. People in low-income neighborhoods where air conditioning can be unaffordable, and renters who often don’t have the same protections for cooling as they do for heating, will be increasingly at risk.
Extreme heat can also impact economies. It can warp rail tracks and cause wires to sag, causing delays and disruptions to public transportation. It can also overwhelm electrical systems with high demand, causing blackouts just when people need cooling the most.
The good news: there are solutions
Yes, the future in a warming world is daunting. While countries are not on track to meet their Paris Agreement goals, they have made progress.
In the US, the Inflation Reduction Act of 2022 could cut greenhouse gas emissions by nearly half by 2035.
Switching from air conditioners to heat pumps and geothermal grid systems can not only reduce fossil fuel emissions but also provide cooling at a lower cost. Renewable energy costs continue to fall and many countries are increasing policy support and incentives.
Humanity can do much to limit future warming if countries, businesses and individuals everywhere act urgently. Rapidly cutting fossil fuel emissions could help prevent a warmer future with even worse heat waves and droughts, while also providing other benefits, including improving public health, creating jobs and reducing risks to ecosystems.
This is an update to an article originally published on June 26, 2024.
This article is republished from The Conversation, a non-profit, independent news organization that brings you facts and reliable analysis to help you understand our complex world. It was written by: Mathew Barlow, UMass Lowell and Jeffrey Basara, UMass Lowell
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Mathew Barlow has received funding from the NOAA Modeling, Analysis, Predictions and Projections Program to study heat waves.
Jeffrey Basara has received funding from the U.S. Department of Agriculture and the National Science Foundation to study sudden drought and extreme temperatures.