From the article you linked:

Posted on: June 23, 2025 at 09:42:25 CT

Of course, modern global warming stems from a clear cause—rising levels of CO2 (and other greenhouse gases) from fossil fuel burning, cutting down forests and other human activities. And, in the past rising CO2 levels at the very least magnified global warming, ushering in the relatively balmy, stable climate sometimes called the "long summer" that has allowed human civilization to flourish. Humanity has now raised global CO2 levels by more than the rise from roughly 180 to 260 ppm at the end of the last ice age, albeit in a few hundred years rather than over more than a few thousand years. "The end of an ice age, you have a sense in your bones what that means: a big, significant change for the planet," Shakun says. "It's a tangible example of what rising CO2 can mean for the planet over the long-term."