A decade ago, I had the privilege of attending and reporting from COP21 in Paris—the year of the so-called "Paris Agreement" was put into place. As I wrote at the time:
We know the overall climate is warming and we need to stop it before it gets worse. But there's some disagreement on what "worse" means, exactly.
The general consensus has been that 2 degrees Celsius is the cutoff for rising global temperatures by the end of the century. Any hotter than that, and it gets increasingly difficult to predict just how unpredictable the ecological damage could be. Also, 2 degrees seemed like a pretty attainable goal for most countries.
There are others, however, who were pushing to cap the rise at 1.5 degrees. And while that half-degree might seem like splitting hairs, there are some parts of the world where it could be the difference between life and death.
This difference between the 2° limit and the 1.5° limit was a major point of contention during the negotiations. Rather than commit to one or the other, the parties agreed that they would, "aim to reach global peaking of greenhouse gas emissions as soon as possible."
Great. Good job. Go team.
Now it looks like 2024 was not only the hottest year on record—the 10th year in a row that we've beat heat records!—but was also the first year in which the average global temperature exceeded that 1.5° limit. That means it wasn't always over 1.5°—but that it still wasn't good. As the BBC explains:
The current trajectory would likely see the world pass 1.5C of long-term warming by the early 2030s. This would be politically significant, but it wouldn't mean game over for climate action.
"It's not like 1.49C is fine, and 1.51C is the apocalypse – every tenth of a degree matters and climate impacts get progressively worse the more warming we have," explains Zeke Hausfather, a climate scientist at Berkeley Earth, a research group in the US.
Even fractions of a degree of global warming can bring more frequent and intense extreme weather, such as heatwaves and heavy rainfall.
In 2024, the world saw blistering temperatures in west Africa, prolonged drought in parts of South America, intense rainfall in central Europe and some particularly strong tropical storms hitting north America and south Asia.
These events were just some of those made more intense by climate change over the last year, according to the World Weather Attribution group.
Meanwhile, Los Angeles is on fire. It is kind of wild to see that the climate has changed pretty much exactly as predicted, and yet somehow some people are still in denial of the very clear reality around them.
2024 first year to pass 1.5C global warming limit [Mark Poynting, Erwan Rivault and Becky Dale / BBC]