This is the first time in human history our planet's atmosphere has had more than 415ppm CO2.
— Eric Holthaus (@EricHolthaus) May 12, 2019
Not just in recorded history, not just since the invention of agriculture 10,000 years ago. Since before modern humans existed millions of years ago.
We don't know a planet like this. https://t.co/azVukskDWr