July 21 was the hottest day on record, European climate agency says

On Sunday, the Earth sizzled to the hottest day ever measured by humans, yet another heat record shattered in the past couple of years, according to the European climate service Copernicus on Tuesday.

Preliminary data from Copernicus shows that the global average temperature Sunday was 17.09 C, beating the record set just last year on July 6, 2023 by 0.01 C. Both Sunday's mark and last year's record obliterate the previous record of 16.8 C, which itself was only a few years old, set in 2016.

Without human-caused climate change, records would be broken nowhere near as frequently, and new cold records would be set as often as hot ones.

"What is truly staggering is how large the difference is between the temperature of the last 13 months and the previous temperature records," Copernius director Carlo Buontempo said in a statement. "We are now in truly uncharted territory and as the climate keeps warming, we are bound to see new records being broken in future months and years."

While 2024 has been extremely warm, what kicked Sunday into new territory was a way-toastier-than-usual Antarctic winter, according to Copernicus. The same thing was happening on the southern continent last year, when the record was set in early July.

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A heat wave has brought record high temperatures to California and Nevada that are already substantially higher than last year. The heat has people searching for ways to stay cool and firefighters working to keep wildfires from spreading.

But it wasn't just a warmer Antarctica on Sunday. Interior California baked with triple-digit Fahrenheit heat, complicating more than two-dozen fires in the U.S. West. At the same time, Europe sweltered through its own deadly heat wave.

"It's certainly a worrying sign coming on the heels of 13 straight record-setting months," said Berkeley Earth climate scientist Zeke Hausfather, who now estimates there's a 92 per centchance that 2024 will beat 2023 as the warmest year on record.

July is generally the hottest month of the year globally, mostly because there is more land in the Northern hemisphere, so seasonal patterns there drive global temperatures.

Copernicus records go back to 1940, but other global measurements by the United States and United Kingdom governments go back even further, to 1880. Many scientists, taking those into consideration along with tree rings and ice cores, say last year's record highs were the hottest the planet has been in about 120,000 years. Now the first six months of 2024 have broken even those.

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Scientists blame the supercharged heat mostly on climate change from the burning of coal, oil and natural gas and on livestock agriculture. Other factors include a natural El Nio warming of the central Pacific Ocean, which has since ended. Reduced marine fuel pollution and possibly an undersea volcanic eruption are also causing some additional warmth, but those aren't as important as greenhouse gases trapping heat, they said.

Because El Nio is likely to be soon replaced by a cooling La Nia, Hausfather said he would be surprised if 2024 sees any more monthly records, but the hot start of the year is still probably enough to make it warmer than last year.

Sunday's mark is notable, but "what really kind of makes your eyeballs jump out" is how the last few years have been so much hotter than previous marks, said Northern Illinois University climate scientist Victor Gensini, who wasn't part of the Copernicus team. "It's certainly a fingerprint of climate change."

WATCH |Copernicus says May was 12th month in a row of record-breaking heat:

May was 12th month in a row of record-breaking heat: EU climate monitor

3 months ago

Duration 4:29

The planet's string of record-breaking temperatures has continued for a full year, with May marking the 12th consecutive month for which its average temperature set a new record for that month, according to new data from Copernicus, the European Union's climate monitoring service..

University of Pennsylvania climate scientist Michael Mann said the difference between the this year's and last year's high mark is so tiny and so preliminary that he is surprised the European climate agency is promoting it.

"We should really never be comparing absolute temperatures for individual days," Mann said in an email.

Yes, it's a small difference, Gensini said in an interview, but there have been more than 30,500 days since Copernicus data started in 1940, and this is the hottest of all of them.

"What matters is this," said Texas A&M University climate scientist Andrew Dessler. "The warming will continue as long as we're dumping greenhouse gases into the atmosphere and we have the technology to largely stop doing that today. What we lack is political will."