Global temperatures likely to exceed key limit for first time
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With October's initial temperature data in, 2024 will rank as the first calendar year in modern record-keeping in which global average surface temperatures exceed the Paris Agreement's aspirational 1.5°C guardrail.
Why it matters: Holding long-term warming to the 1.5-degree target compared to the preindustrial era is crucial for lowering the risk of triggering climate change tipping points, beyond which potentially catastrophic impacts have a higher likelihood of occurring, studies show.
- Holding warming to that target is viewed as necessary for small island states and other extremely vulnerable nations to avoid being wiped out by sea level rise, drought and other threats.
The data — and proxy records such as tree rings and ice cores — shows this year is likely to be the hottest in at least 125,000 years.
State of play: Right now, the world is on track for as much as 3.1°C (5.58°F) of warming based on already pledged emissions cuts, assuming they are fulfilled.
Zoom in: Copernicus Climate Change Service reported early Thursday that the year is headed for a temperature anomaly of more than 1.55°C (2.79°F) above preindustrial levels.
- Last year fell just shy of the 1.5°C threshold relative to the 1850-1900 average.
- That raised concerns among climate scientists that global warming may be accelerating more than can be explained by temporary, well-known factors, such as El Niño, an air and ocean cycle in the tropical Pacific.
- It is likely that this year's record global temperature will fuel more conversations within the scientific community, since there was an expectation that 2024 would fall below 2023 on the list of warmest years.
The intrigue: If the projection is verified in January, 2024 would be the warmest year since Copernicus' data set began in 1940.
- In addition, it isn't just a calendar year that has been extremely warm compared to levels seen prior to the burning of fossil fuels such as coal, oil and gas for energy.
- October was the 15th month out of a 16-month period with global average surface temperatures exceeding 1.5°C compared to the preindustrial era.
Yes, but: While one year with global average temperatures exceeding the 1.5°C target is noteworthy, the Paris Agreement refers to a 30-year average, so the target hasn't technically been breached.
- Still, the fact that this warming limit is now being regularly met or slightly exceeded indicates how close the world is to zooming past it on a longer-term basis.
What we're watching: The temperature numbers arriving mid-month from NOAA and NASA.
