Today, six climate agencies from around the world confirmed what we knew was coming: Earth has once again experienced its hottest year on record.
But whether it has exceeded 1.5°C above the pre-industrial average depends on which climate agency you look at.
According to the EU's Copernicus Climate Change Service, 2024 was the warmest year on record since 1850, reaching 1.6 °C above the pre-industrial average (1850-1900). It beat 2023 as the warmest year on record, which was 1.48°C warmer than the pre-industrial average.
However, according to NASA, 2024 was 1.47°C warmer than the pre-industrial average, hovering around 1.5°C.
The National Oceanic and Atmospheric Administration (NOAA) said it was 1.46°C warmer.
Berkeley Earth, a nonprofit climate analysis organization, also found that 2024 was 1.62°C warmer than the pre-industrial average.
The numbers vary by agency because of how climate agencies collect past data.
However, the World Meteorological Organization looked at all these analyses, as well as those from the UK Meteorological Office and the Japan Meteorological Agency, and concluded that we are “likely” to exceed 1.5°C of warming in 2024.
However, the consensus is that the last 10 years have been the warmest on record.
Although this may be the first calendar year in which the 1.5°C threshold set out in the regulation was exceeded Paris AgreementHowever, this does not mean that we have broken this agreement. This threshold – a commitment by 195 countries to keep global warming below 1.5°C above the pre-industrial average – applies for many years in which the Earth's temperature remains consistently above that level, not just for one or two years .
That also doesn't mean there's no hope of keeping warming from exceeding this target. As climate scientists often say:every fraction of a degree matters“
This is not the first 12-month period of warming above this threshold. From mid-2023 to mid-2024, the planet was 1.5°C warmer. Except it didn't happen within a calendar year.
Does 1.5 really matter?
While there may be some disagreement on the exact amount of warming – on the order of hundredths of a degree – the message is the same: The Earth is getting warmer.
“We can say that the 1.5 limit will probably be exceeded in 2024,” said Gavin Schmidt, director of the Space Studies Institute. Goddard at NASA. “But the impact that we see if it's 1.48 or 1.52 or 1.6, you know, is almost the same.”
“We are seeing increased rainfall intensity, increased heatwaves and rising sea levels. All these things don't really depend on the little details of the last comma,” Schmidta said.
According to World Weather Attribution (WWA), climate-related disasters contributed to the deaths of at least 3,700 people and the displacement of millions of people as a result of 26 weather events studied in 2024.
In its December report, WWA noted that: “This was only a small fraction of the 219 events that met our trigger criteria used to identify the most impactful weather events. This is likely the total number of people killed by extreme weather events exacerbated by climate. changes this year number in the tens or hundreds of thousands.”
When will we know that we have crossed the threshold of the Paris Agreement?
While 2024 started with high temperatures, driven by El Niño – a natural, cyclical warming in the Pacific Ocean region that, when combined with the atmosphere, could cause global temperatures to rise – this is not the case in 2025.
“This year, 2025, we start with a mild landing year, a bit cool,” Schmidt said. “It will be a contrast between 2025 and 2024: we start from a colder level. So we expect 2025 to be colder than 2024, but perhaps not by much.”
Instead of El Niño, we are starting with a La Niña recommendation, which may lower global temperatures somewhat.
Even if 2025 brings a colder year, the trend is for Earth's temperature to continue to rise.
Unprecedented wildfires in Los Angeles County are being fueled by unseasonably dry weather and hurricane-force winds, and experts warn the problem isn't unique to California.
However, knowing when we will exceed the 1.5°C threshold set by the Paris Agreement is difficult.
“The general interpretation, including the latest report of the Intergovernmental Panel on Climate Change, is that the pre-industrial period means 1850-1900, and meeting the target means that the 20-year average exceeds 1.5 degrees,” said Zeke Hausfather, a staff member scientific in Berkeley land.
“The problem with this definition, of course, is that we won't actually know when we have exceeded 1.5 degrees until 10 years after we have exceeded 1.5 degrees, which is not a very useful definition,” he said.
But Hausfather noted that climate scientists are trying to find a better way to make such decisions earlier.
Still, he said: “We will probably definitely exceed 1.5 degrees in the next five to 10 years.”
And while it may be tiring to hear that another year is one for the record books, no matter where that year is, Schmidt said there is a reason for it.
“The same story happens every year or so as long-term trends are driven by fossil fuel emissions and they continue to do so,” he said. “Until they stop, we will continue the same conversation. Do I sound like a broken record? Yes, because we keep breaking records.”
Hausfather also worries about the continued upward trend in temperatures.
“The climate is a raging beast,” he said. “We should stop poking him with sticks.”