Today, six climate organizations from around the world confirmed what we knew was coming: Earth once again had its hottest year on record.
But whether or not it exceeded 1.5 C above the pre-industrial average depends on which climate group you look at.
According to the EU's Copernicus Climate Change Service, 2024 will be the warmest year on record dating back to 1850, coming in at 1.6 C above the pre-industrial average (1850-1900 ). It beat 2023 as the hottest 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, going ever closer to 1.5 ° C.
The National Oceanic and Atmospheric Administration (NOAA) found it to be 1.46 C warmer.
Berkeley Earth, a non-profit climate research group, also found that 2024 was 1.62 C warmer than the pre-industrial average.
The numbers vary among the groups because of how climate groups have collected data in the past.
However, the World Meteorological Organization looked at all these analyses, as well as those from the UK Met Office and the Japan Meteorological Agency, and found that we are “likely” to exceed 1.5 C of warming by 2024.
But what is agreed upon is that the past 10 years have been the warmest on record.
Although this may be the first calendar year to exceed the 1.5 C threshold defined in the The Paris Agreementit does not mean that we have broken that agreement. That threshold – the pledge from 195 countries to keep global warming below 1.5 C of the pre-industrial average – applies to a number of years where the Earth's temperature is consistently above that, not just one or two.
And it also does not mean that there is no hope of continuing to warm up from passing that goal. As climate scientists often say, “every fraction of a step is important.”
This is not the first 12 months of warming above that threshold. From mid-2023 to mid-2024, the planet was 1.5 C warmer. It just didn't happen over a calendar year.
Is 1.5 really important?
Although there may be some disagreement as to the exact rate of warming – in only hundreds of degrees – the message is the same: the Earth is getting warmer.
“We can say, I think, that 2024 seems to have broken the limit of 1.5,” said Gavin Schmidt, director of NASA's Goddard Institute for Space Studies. 'see, if it's like 1.48 or 1.52 or 1.6 you know, they're almost the same.”
“We're seeing more rain, we're seeing more heat, we're seeing sea level rise. All of these things don't really depend on the details of the decimal point about after that,” said Schmidt.
According to the World Weather Attribution (WWA), climate-related disasters contributed to the deaths of at least 3,700 people and the displacement of millions in the 26 weather events they studied in 2024.
In its December report, WWA noted, “Only a small fraction of the 219 events met our trigger criteria, which were used to identify the most impactful weather events. the change this year is in the tens or hundreds of thousands.”
When will we know we have passed the threshold of the Paris Agreement?
While 2024 began with high temperatures, fueled by El Niño – a natural, cyclical warming in an area of the Pacific Ocean that, along with the atmosphere, could increase global temperatures – that is not the case for 2025.
“This year, 2025, we're starting with kind of a layoff year, a little bit on the cool side,” Schmidt said. “So that will be the difference between 2025 and 2024: we are starting at a cooler level. So we expect 2025 to be cooler than 2024 but maybe not by much.”
Instead of El Niño, we are starting with a La Niña advisory, which will bring global temperatures slightly lower.
Even though 2025 will bring a cooler year, the trend is that the Earth's temperature is moving steadily upwards.
Unprecedented wildfires in Los Angeles County have been fueled by unusually dry weather and hurricane-force winds, and experts warn the problem is not unique to California.
But it is difficult to know when we will pass the 1.5 C threshold of the Paris Agreement.
“It is generally defined, including the most recent report (Intergovernmental Panel on Climate Change), that pre-industrial means 1850 to 1900, and passing the target means the 20-year time average is over 1.5 degrees,” said Zeke Hausfather, research scientist at Berkeley land.
“The problem with that definition, of course, is that we won't really know when we passed 1.5 degrees until 10 years after we passed 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 that decision faster.
But, he said, “We're probably going to go past 1.5 levels solidly in the next five to 10 years. “
And while it might be tiring to hear that there's another year for the records wherever it is, Schmidt said there's a reason.
“It's the same story every year or two, because the long-term trends are driven by our fossil fuel emissions, and they haven't stopped,” he said. Until they stop, we are going to continue with the same conversation. And so, do I feel like a broken record? Yes, yes, because we keep broken records.”
For Hausfather, he is also concerned about the continued trend of rising temperatures.
“Climate is an angry animal,” he said. “We should stop it with sticks.”
