Thanks to SteveoR for showing this to me!
The video shows a graph of the rise of atmospheric CO2 levels over the second half of the 20th century, into the 21st. Then it starts to “zoom out”, showing falling levels, back into the last ice age, rising before it, falling again for another ice age, and so on back to eight hundred thousand years BCE. As longer periods of time become visible on the graph, the timeline compresses, showing the last 50 years or so for the very short time that they represent. Well before the end of the video, it is clear that CO2 levels are far, far higher now than they have been at any point in the last 800,000 years, and beyond.