Summer 2024 was the hottest on record, surpassing last year

Summer 2024 was the hottest on record, surpassing last year

TO Saima S. Iqbal

In Japan, more than 70,000 people went to emergency rooms for heatstroke in July and August alone. Iran faces a relentless heat wave closed government offices, banks and schools. And US cities like Phoenix, Arizona, and Las Vegas have seen weeks of high temperatures above 100 degrees Fahrenheit (38 degrees Celsius). These are just some of the markers of what European and US climate agencies have found to be the hottest June to August months on record, and they offer a glimpse of how further warming could change the planet.

This new summer record, an average temperature of 62.2 degrees Fahrenheit (16.8 degrees Celsius), beats last summer's extremely high average by just 0.05 degrees Fahrenheit (0.03 degrees Celsius). Both marks are the highest summer averages since 1850. However, ancient tree ring studies suggest that temperatures in 2023 and, by extension, 2024, will be the hottest in the last 2000 years. And some climate scientists have calculated that the average summer readings for those two years could be the highest in the past 125,000 years; at that distant time in Earth’s history, hippos swam the waters around Britain and forests dotted the Arctic. The US National Oceanic and Atmospheric Administration’s National Centers for Environmental Information now says there’s a 97 percent chance that 2024 will surpass 2023 as the hottest full year on record.

Hot June and August contributed greatly to this summer's record, with both months breaking or equaling Heat records 2023with the Earth's average surface temperature at least 2.7 degrees Fahrenheit (1.5 degrees Celsius) above pre-industrial levels. In 2016, as part of the Paris climate accords, countries agreed to try to keep global warming below that threshold, though that target is a multi-year average rather than individual months. If July had been slightly hotter, the planet could have claimed a 14-month streak of temperatures above the threshold. (July saw the hottest day on record record(However, on July 22, the global average temperature reached 62.89 degrees Fahrenheit (or 17.16 degrees Celsius), about three degrees Fahrenheit (or 1.7 degrees Celsius) above the pre-industrial average.) This year, 15 countries from Mexico to Chad have set record high temperatures, and 130 national monthly records have been broken.

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That record reflects the scale of human-caused climate change. Global temperature records do cluster around El Niño events, the most recent of which began in late 2023 and ended in May 2024. This complex climate pattern results in a significant release of heat from the tropical oceans into the atmosphere. But El Niño contributes only 0.36 degrees Fahrenheit (0.2 degrees Celsius) to global temperatures and cannot, on its own, cause the rapid changes the planet is now experiencing. “Human greenhouse gas emissions are actually adding a steady amount of El Niño heat every decade,” says Zeke Hausfather, a climate scientist with the nonprofit Breakthrough Institute. He notes that other unknown factors are likely at play, too, since scientists estimate that up to a third of the planet’s observed warming during 2023 and 2024 is not explained by human-caused climate change or El Niño.

The Earth has experienced more extreme temperatures in the past, but those extreme temperatures have increased more gradually. “These are geological trends that typically occur over millions or thousands of years,” says Angel Fernandez-Bou, a biosystems engineer at the University of California, Merced. “Now that [same] The temperature increase has been going on for decades.” As a result, scientists fear that the planet is warming too quickly for living things and their environments to have time to adapt.

For example, modern sewage systems may not be able to withstand increasingly intense rainfall. Our bodies won’t be able to withstand as much time outdoors — or indoors without air conditioning — as heat waves become more intense and frequent. More frequent wildfires are expected to destroy thousands of acres of crops and pastures. And past adaptation efforts have proven slower and more costly than previously thought, Hausfather notes.

While global and national temperature records provide clear indications of how much excess heat greenhouse gases have trapped in the atmosphere, real people do not live in average temperatures. Such measurements can mask wide regional differences and extremes. In the southwestern United States, successive summer heat domes have created one of the hottest places on the planet: as of Sept. 4, Phoenix has seen temperatures above 100 degrees Fahrenheit for more than 100 days. consecutive days. That broke the city’s previous record of 76 consecutive days, set in 1993. The July heat wave burdened Olympic athletes in Paris, spread wildfires in Portugal and Greece, and worsened water shortages in Italy and Spain. Even the southern hemisphere, where winter was occurring, languished from June to August. Across Australia, it was often more like summer, with national temperatures 5.4 degrees Fahrenheit (3 degrees Celsius) above normal during August, and one remote region of Western Australia recording a record 107 degrees Fahrenheit (41.6 degrees Celsius). In July, regions of winter Antarctica saw temperatures 50 degrees Fahrenheit (28 degrees Celsius) above normal.

The planet will continue to break heat records until humans stop producing greenhouse gases, says Andrew Dessler, a climate scientist at Texas A&M University. With renewable energy now cheaper than fossil fuels, the biggest barrier to meaningful action is not technological but political, he says. That means “the solution is in our hands,” Dessler says.

Greenhouse gas emissions have remained stable over the past decade, at least preventing further acceleration of warming. However, stopping further increases in global temperatures will require ending emissions from burning fossil fuels and other sources such as deforestation and agriculture. Climate scientists now predict that the planet will pass the 1.5 degrees Celsius threshold set by the Paris Agreement by the end of this decade or early next.

“But that doesn't mean the climate will go from being great to being in a fire once the world crosses 1.5 degrees,” Hausfather emphasizes. “Every tenth of a degree matters: the more warming, the worse the consequences.”