Why it’s not ‘just summer’ here, and what climate change has to do with it

One month in the summer of 2024, the vast majority of the US population experienced at least one extreme heat wave, and millions of people were under heat alerts, with forecasts warning that more were ahead.

Death Valley hit 125 degrees Fahrenheit (51.7 Celsius) or higher for nine days in a row in early July. Las Vegas broke his all-time heat record at 120 F (48.9 C). Days of 100-degree heat parched the California landscape, fueling wildfires there and in the Northwest. Oregon has reported several suspected heat deaths.

Globally, the planet had its hottest day in at least eight decades of record-keeping on July 21 – and then broke the record again on July 22, according to the European Union’s Copernicus Climate Change Service.

The extreme heat is part of a longer trend: Each of the past 13 months has been the hottest on record for that month worldwide, including the hottest June, which the EU service reported early July. It also found that the average temperature for the previous 12 months was at least 1.5 C (2.7 F) warmer than the 1850-1900 pre-industrial average.

A chart shows the annual averages with the trend line going out another 10 years before crossing the 1.5 C for the 30 year average.

The 1.5 C warming threshold can be confusing, so let’s take a closer look at what that means. In the Paris climate agreement, countries around the world agreed to work to keep global warming below 1.5 C, but that refers to the average temperature change over a period of 30 years. A 30-year average is used to limit the impact of natural fluctuations from year to year.

So far, Earth has only crossed that threshold for one year. However, he is still extremely worried. We study weather patterns related to heat. The world appears to be on track to cross the 30-year average threshold of 1.5 C within 10 years.

Heat is becoming a global problem

Several countries across the Americas, Africa, Europe and Asia experienced record heat in 2024. In Mexico and Central America, weeks of persistent heat that began in the spring of 2024 combined with a prolonged drought severe water shortages and many deaths.

Tragedy came from the extreme heat in Saudi Arabia, where more than 1,000 people collapsed and died on the Hajj, a Muslim pilgrimage to Mecca. The temperature reached 125 F (51.8 C) at the Grand Mosque in Mecca on June 17.

A large number of people in traditional clothes that cover them from the neck to the wrists and ankles walk on a wide path, some of them carrying umbrellas for shade.A large number of people in traditional clothes that cover them from the neck to the wrists and ankles walk on a wide path, some of them carrying umbrellas for shade.

Hospitals in Karachi, Pakistan, were under siege amid weeks of high heat, frequent power outages, and water shortages in some areas. Temperatures hovered around 120 F (48.9 C) across neighboring India for several days in April and May, affecting millions of people, many without air conditioning.

Japan issued heat stroke warnings in Tokyo and more than half of its predecessors as temperatures rose to their highest level in early July.

Large parts of Europe have been suffering through a prolonged heat wave as the 2024 Summer Olympics prepare to open in Paris at the end of July.

The climate link: This is not ‘just summer’

Although heat waves are a natural part of the climate, the intensity and extent of heat waves so far in 2024 is not “just summer”.

A scientific assessment of the extreme heat wave in the eastern US in June 2024 estimates that such intense and prolonged heat was two to four times more likely today due to human-caused climate change than it would have been. without it. This conclusion is consistent with the rapid increase over the past few decades in the number of heat waves in the US and their occurrence outside of the summer peak.

The largest heat waves on record are occurring in a climate that is over 2.2 F (1.2 C) worldwide warmer – when looking at the 30-year average – than it was before the industrial revolution, when people started large amounts of greenhouse gas emissions were released that were warming. the climate.

Two global maps show much faster warming per decade in the last 30 years than in the last 120 years.Two global maps show much faster warming per decade in the last 30 years than in the last 120 years.
Global surface temperatures have risen faster in the last 30 years than in the last 120 years. NOAA NCEI

Although a temperature difference of a degree or two may not be noticeable when you walk into another room, even fractions of a degree make a big difference in global climate.

At the peak of the last ice age, about 20,000 years ago, when the Northeastern US was under thousands of feet of ice, the average global temperature was only about 11 F (6 C) cooler than it is now. So, it’s not surprising that 2.2 F (1.2 C) of warming so far is already rapidly changing the climate.

If you thought this was hot

Although this summer is likely to be one of the hottest on record, it is important to realize that it could be one of the coldest summers to come.

For populations particularly vulnerable to heat, including young children, older adults and outdoor workers, the risks are even higher. People in lower-income neighborhoods where air conditioning may be unaffordable and renters who often don’t have the same protections for cooling and heating will face more dangerous conditions.

Extreme heat can also affect economies. It can buckle railroad tracks and cause wires to snap, causing transit delays and disruptions. It can also overload high-demand electrical systems and lead to blackouts right when people need cooling the most.

The good news: There are solutions

Yes, the future in a warming world is scary. However, while countries are not on track to meet their Paris Agreement targets, they have made progress.

In the United States, the Inflation Reduction Act of 2022 has the potential to cut US greenhouse gas emissions by nearly half by 2035.

Switching from air conditioners to heat pumps and geothermal network systems will not only reduce fossil fuel emissions but also provide lower cost cooling. The cost of renewable energy continues to fall, and many countries are increasing policy support and incentives.

A chart shows that the number of heat waves is likely to be four times higher in a 2.7 F (1.5 C) warmer world and almost five times higher in a 6.3 F (3.5 C) warmer world.  Both scenarios are possible as global emissions rise.A chart shows that the number of heat waves is likely to be four times higher in a 2.7 F (1.5 C) warmer world and almost five times higher in a 6.3 F (3.5 C) warmer world.  Both scenarios are possible as global emissions rise.

There is much humanity can do to limit future warming if countries, companies and people everywhere act urgently. Rapidly reducing fossil fuel emissions can help avoid a warmer future and worse heat waves and droughts, while providing other benefits, including improved public health, jobs create and reduce risks to ecosystems.

This is an update to an article originally published on 26 June 2024.

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. Written by: Mathew Barlow, UMass Lowell and Jeffrey Basara, UMass Lowell

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Mathew Barlow has received funding from NOAA’s Modeling, Analysis, Projections and Projections Program to study heat waves.

Jeffrey Basara has received funding from the United States Department of Agriculture and the National Science Foundation to study flash drought and extreme temperatures.

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