Warmest April on record extends planet's hot streak to 11 months

A vendor prepares his umbrella as hot days continue in Manila, Philippines on Monday, April 29, 2024. Millions of students in all public schools across the Philippines were ordered to stay home Monday after authorities cancelled in-person classes for two days as an emergency step due to the scorching heat and a public transport strike. (AP Photo/Aaron Favila)
A vendor in Manila seeks shade from the sun. Southeast Asia has been gripped by an extreme heat wave. (Aaron Favila / Associated Press)

Earth's simmering hot streak has stretched 11 months, with April breaking yet another global temperature record.

It was warmer than any April on record, with an average surface temperature of 59.05 degrees, officials with the European Union's Copernicus Climate Change Service announced this week. It was about 0.25 of a degree warmer than the previous April high, in 2016.

April was 2.84 degrees warmer than the estimated average for the month from 1850 to 1900, the designated pre-industrial reference period against which current warming is measured.

International climate officials have pledged to limit planetary warming to 2.7 degrees (1.5 degrees Celsius) in order to prevent the worst effects of climate change, including worsening drought and wildfires, rising sea levels and extreme heat.

Some of the recent run of heat can be attributed to El Niño, a climate pattern in the tropical Pacific that influences temperature and weather conditions around the world, experts said. But El Niño has been waning, and global warming fueled by fossil fuel emissions continues to be the primary driver of high temperatures.

"El Niño peaked at the beginning of the year and the sea surface temperatures in the eastern tropical Pacific are now going back towards neutral conditions," Copernicus Director Carlo Buontempo said in a statement. "However, whilst temperature variations associated with natural cycles like El Niño come and go, the extra energy trapped into the ocean and the atmosphere by increasing concentrations of greenhouse gases will keep pushing the global temperature towards new records."

Read more: The planet is dangerously close to this climate threshold. Here's what 1.5°C really means

Though 11 consecutive months of record-breaking temperatures are unusual, it's not the first time the planet has seen such a streak. A similar run occurred in 2015-16, according to Copernicus. However, the global average temperature for the past 12 months — May 2023 through April — is the highest on record.

"Maybe I'm a little surprised at the magnitude, but I'm not surprised at all that this was far and away the warmest year on record," said Emily Becker, lead writer of the National Oceanic and Atmospheric Adminstration's El Niño-Southern Oscillation blog. "With the combination of global warming and El Niño, I think this is what we can expect."

California experienced a relatively cool April compared with other parts of the world. The worst of the month's heat bore down in northern and northeastern North America, eastern Europe, Greenland, eastern Asia, the northwest Middle East, parts of South America and most of Africa, according to Copernicus.

Southeast Asia, in particular, has been gripped by an extreme heat wave that began in April and has continued for weeks, contributing to dozens of deaths. Bangladesh, Thailand, Cambodia and the Philippines are among the countries most acutely affected, with triple-digit temperatures prompting school closures and contributing to devastating crop loss.

Officials in Chauk, Myanmar, in April reported a high temperature of 118.8 degrees.

Read more: 'Humbling, and a bit worrying': Scientists fail to fully explain record global heat

Oceans were also hot across the world last month, with sea surface temperature averaging 69.9 degrees — the highest value on record for April and only a few tenths of a degree cooler than the readings from March.

It is the 13th month in a row that the sea surface has had record high temperatures, Copernicus said.

Antarctic sea ice extent was 9% below average — the 10th lowest extent on record for April — while Arctic sea ice extent was about 2% below average, a relatively small anomaly compared with readings for the month over the past 10 years.

Some officials are hopeful that El Niño's retreat could bring relief from the hot spell. There is an 85% chance that El Niño's cooler counterpart, La Niña, will develop by fall or early winter, according NOAA's most recent outlook.

Becker said models are predicting "a small decrease in the global mean temperature" over the next nine months, but not a substantial drop. The fact that the most recent record-hot months occurred despite El Niño's waning strength indicates that, even without its influence, global warming and other factors are continuing to keep temperatures high.

"Given that the global mean temperature was much higher than would have been expected with just the impact of El Niño, we expect to see the global mean temperature stay well above the average," said Becker, an associate scientist at the University of Miami.

Read more: La Niña on the horizon? California's wild weather year could get even weirder

While La Niña may bring a slight reduction in heat, it does carry other risks, including the potential for an active Atlantic hurricane season and a return to dry conditions in California. La Niña was most recently in place from 2020 to 2023 — a period that included California's driest three years on record.

What's more, forecasts indicate that another hot summer could be in store for the United States and other parts of the world. That includes increased odds of above-normal temperatures in every part of the continental U.S. in July, August and September, according to NOAA's latest seasonal outlook.

Regions of the U.S. most likely to experience soaring temperatures fall along a diagonal stretch from Idaho to Texas, as well as in the far Northeast. The outlook for California shows a 33%-40% chance of above-normal temperatures along the coast and a 40%-50% chance of above-normal temperatures in inland areas and the northernmost counties.

With four hot months already recorded, it's "very likely" that 2024 could challenge 2023's title as Earth's warmest year on record, Becker said.

Zeke Hausfather, a climate scientist with Berkeley Earth, said in a post on X that there is a 66% chance that 2024's heat will surpass that of last year. There is a 99% chance it will be one of the two warmest years — at least so far.

This story originally appeared in Los Angeles Times.