It’s happened before, and we’ve observed it indirectly.
The last time the northern Atlantic current shut down, parts of Western Europe were covered in glaciers.
The climate models are extremely accurate within certain ranges. When you get outside those ranges, previously unknown tipping points like this will start to manifest themselves.
It’s the difference between predicting what a piece of precision machinery will do when it’s new vs after it’s been dropped and hit with a sledgehammer.
This is why the 1.5C global warming goal was irresponsibly high. We’ll cross it in ~ 18 months, so expect more terrible news like this article’s findings as we get further and further away from well-understood climatology.
"The global annual average for 2024 in our dataset is estimated as 1.62 ± 0.06 °C (2.91 ± 0.11 °F) above the average during the period 1850 to 1900, which is traditionally used a reference for the pre-industrial period. This is first time Berkeley Earth has reported an annual average above 1.6 °C (2.9 °F), and the only second time that Berkeley Earth has reported any year exceeding the key 1.5 °C (2.7 °F) threshold, after slightly doing so in 2023."
I have no source for this other than having read a number of surveys, but as I understand it, you will get most climate scientists to agree we probably won’t go past 4°C. That seems way more realistic to me, since this is such a high friction project.
The last time the northern Atlantic current shut down, parts of Western Europe were covered in glaciers.
The climate models are extremely accurate within certain ranges. When you get outside those ranges, previously unknown tipping points like this will start to manifest themselves.
It’s the difference between predicting what a piece of precision machinery will do when it’s new vs after it’s been dropped and hit with a sledgehammer.
This is why the 1.5C global warming goal was irresponsibly high. We’ll cross it in ~ 18 months, so expect more terrible news like this article’s findings as we get further and further away from well-understood climatology.