Earth records hottest year ever in 2024 and the jump was so big it breached a key threshold

Michael Mullenax, 10, from Lee's Summit, Mo., cools off in a mister at Kauffman Stadium before a baseball game between the Kansas City Royals and the Miami Marlins, June 24, 2024, in Kansas City, Mo. (AP Photo/Charlie Riedel, File)

Earth recorded its hottest year ever in 2024, with such a big jump that the planet temporarily passed a major climate threshold, several weather monitoring agencies announced Friday.

Last year's global average temperature easily passed 2023's record heat and kept pushing even higher. It surpassed the long-term warming limit of 1.5 degrees Celsius (2.7 degrees Fahrenheit ) since the late 1800s that was called for by the 2015 Paris climate pact, according to the European Commission's Copernicus Climate Service, the United Kingdom's Meteorology Office and Japan's weather agency.

The European team calculated 1.6 degrees Celsius (2.89 degrees Fahrenheit) of warming. Japan found 1.57 degrees Celsius (2.83 degrees Fahrenheit) and the British 1.53 degrees Celsius (2.75 degrees Fahrenheit) in releases of data coordinated to early Friday morning European time.

American monitoring teams — NASA, the National Oceanic and Atmospheric Administration and the private Berkeley Earth — were to release their figures later Friday but all will likely show record heat for 2024, European scientists said. The six groups compensate for data gaps in observations that go back to 1850 — in different ways, which is why numbers vary slightly.

“The primary reason for these record temperatures is the accumulation of greenhouse gases in the atmosphere” from the burning of coal, oil and gas, said Samantha Burgess, strategic climate lead at Copernicus. “As greenhouse gases continue to accumulate in the atmosphere, temperatures continue to increase, including in the ocean, sea levels continue to rise, and glaciers and ice sheets continue to melt.”

Last year eclipsed 2023's temperature in the European database by an eighth of a degree Celsius (more than a fifth of a degree Fahrenheit). That's an unusually large jump; until the last couple of super-hot years, global temperature records were exceeded only by hundredths of a degree, scientists said.

The last 10 years are the 10 hottest on record and are likely the hottest in 125,000 years, Burgess said.

July 10 was the hottest day recorded by humans, with the globe averaging 17.16 degrees Celsius (62.89 degrees Fahrenheit), Copernicus found.

By far the biggest contributor to record warming is the burning of fossil fuels, several scientists said. A temporary natural El Nino warming of the central Pacific added a small amount and an undersea volcanic eruption in 2022 ended up cooling the atmosphere because it put more reflecting particles in the atmosphere as well as water vapor, Burgess said.

Alarm bells are ringing

“This is a warning light going off on the Earth’s dashboard that immediate attention is needed,'' said University of Georgia meteorology professor Marshall Shepherd. ”Hurricane Helene, floods in Spain and the weather whiplash fueling wildfires in California are symptoms of this unfortunate climate gear shift. We still have a few gears to go."

"Climate-change-related alarm bells have been ringing almost constantly, which may be causing the public to become numb to the urgency, like police sirens in New York City," Woodwell Climate Research Center scientist Jennifer Francis said. "In the case of the climate, though, the alarms are getting louder, and the emergencies are now way beyond just temperature.”

The world incurred US$140 billion in climate-related disaster losses last year — third highest on record — with North America especially hard hit, according to a report by the insurance firm Munich Re.

“The acceleration of global temperature increases means more damage to property and impacts on human health and the ecosystems we depend on,” said University of Arizona water scientist Kathy Jacobs.

World breaches major threshold

This is the first time any year passed the 1.5-degree threshold, except for a 2023 measurement by Berkeley Earth, which was originally funded by philanthropists who were skeptical of global warming.

Scientists were quick to point out that the 1.5 goal is for long-term warming, now defined as a 20-year average. Warming since pre-industrial times over the long term is now at 1.3 degrees Celsius (2.3 degrees Celsius).

“The 1.5 degree C threshold isn’t just a number — it’s a red flag. Surpassing it even for a single year shows how perilously close we are to breaching the limits set by the Paris Agreement,” Northern Illinois University climate scientist Victor Gensini said in an email. A 2018 massive United Nations study found that keeping Earth's temperature rise below 1.5 degrees Celsius could save coral reefs from going extinct, keep massive ice sheet loss in Antarctica at bay and prevent many people's death and suffering.

Francis called the threshold “dead in the water.”

Burgess called it extremely likely that Earth will overshoot the 1.5-degree threshold, but called the Paris Agreement “extraordinarily important international policy” that nations around the world should remain committed to.

More warming is likely

European and British calculations figure with a cooling La Nina instead of last year's warming El Nino, 2025 is likely to be not quite as hot as 2024. They predict it will turn out to be the third-warmest. However, the first six days of January — despite frigid temperatures in the U.S. East — averaged slightly warmer and are the hottest start to a year yet, according to Copernicus data.

Scientists remain split on whether global warming is accelerating.

There's not enough data to see an acceleration in atmospheric warming, but the heat content of the oceans seem to be not just rising but going up at a faster rate, said Carlo Buontempo, Copernicus' director.

“We are facing a very new climate and new challenges — climate challenges that our society is not prepared for,” Buontempo said.

This is all like watching the end of “a dystopian sci-fi film,” said University of Pennsylvania climate scientist Michael Mann. “We are now reaping what we've sown.”

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