July 21 was Earth’s hottest day in all recorded history, European climate agency says

“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.

But it wasn’t just a warmer Antarctica on Sunday. Interior California baked with triple digit heat Fahrenheit, complicating more than two dozen fires in the US 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% chance 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.

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 Nino 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 Nino is likely to be soon replaced by a cooling La Nina, 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.

Sure 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.”

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.”