2024: Earth's hottest year and first to exceed Paris target
Last year was Earth's warmest on record, eclipsing 2023's record and for the first time exceeding the Paris target of 1.5Β°C above preindustrial levels, the Copernicus Climate Change Service announced Thursday.
Why it matters: While climate scientists don't put too much stock into an individual year's record, the long-term trend is toward more rapid warming, and it is not entirely clear why 2024 was so hot β and what it portends.
Zoom in: Last year was the hottest seen in instrument record-keeping, but also much longer before that.
- In fact, as with 2023, the year was very likely the hottest in at least 125,000 years.
- Some daily global average temperatures, as measured using increasingly precise computer model data, exceeded 2Β°C above preindustrial levels β flirting with another temperature target in the Paris Climate Agreement.
According to Copernicus, an agency of the European Commission, each year in the last decade has been one of the 10 hottest on record.
- Data from U.S. centers, such as NOAA and NASA, show similar results. (Their final 2024 data comes out Friday.)
- Global average surface temperatures in 2024 were about 1.6Β°C above pre-industrial levels, Copernicus found, and about 0.12Β°C (.22Β°F) above 2023's record high.
Yes, but: The Paris Agreement's most stringent temperature target of holding warming to 1.5Β°C compared with pre-industrial levels refers to a long-term, 20-to-30-year average, rather than a single year or two.
- Still, 2024 shows the world is already exceeding the barrier that diplomats set at the Paris climate summit in 2015, and in fact the average of 2023 and 2024 falls above the 1.5Β°C threshold, Copernicus said.
- Studies show that if warming exceeds 1.5Β°C relative to preindustrial levels, the odds of potentially catastrophic impacts, such as the shutting of key ocean currents and melting of Arctic and Antarctic ice sheets, would increase considerably.
- Regarding exceeding the 1.5Β°C marker, Copernicus' news release stated: "Global temperatures are rising beyond what modern humans have ever experienced."
What they're saying: "Humanity is in charge of its own destiny but how we respond to the climate challenge should be based on evidence," said Carlo Buontempo, the Copernicus Climate Change Service's director.
- "The future is in our hands β swift and decisive action can still alter the trajectory of our future climate."
Between the lines: One of the most impactful records seen during 2024 was unusually high amounts of water vapor in the atmosphere, at about 5% above the 1991-2020 average, beating previous highs.
- Extreme heat and high humidity is a deadly combination, and record large swaths of the globe saw "strong" to "extreme heat stress," per Copernicus' data.
- The high water vapor content in the atmosphere also helped contribute to extreme precipitation events, and to rapidly intensifying tropical cyclones, such as hurricanes Helene and Milton.
The intrigue: Climate scientists are still investigating why 2024, which didn't feature a planet-warming El NiΓ±o event on top of human-caused climate change, vaulted above 2023 on the list of hottest years.
- Multiple studies have been published on this topic, and the possibility that the climate has shifted into a new phase of more rapid warming for reasons that are not yet completely clear is unnervingly still on the table.
What's next: Along with NOAA's and NASA's climate reports on Friday will come a new report on trends in ocean heat content.
- All of it is likely to show evidence of a planet heating faster and to record levels.