The planet has now experienced an entire year where atmospheric carbon dioxide has exceeded 400 parts per million, the agreed upon standard considered a threshold for climate change.
It is now more than 100 ppm, or 33% greater, than any time in the last 800,000 years.
The steady rise with the start of the Industrial Revolution is apparent when looking at the data from 1700 to the present. That strongly suggests a recent cause.
This is not news for most, but a useful reminder.
(Click on any of the graphs for links to the interactive data.)