The plot is weird: The title of the plot ("Isens alder (år )") literally means "age of the ice (years)", so the x-axis should probably have gone from 0 (being year 2016) to 116 (being year 1900), which would sorta have made sense.

Agreed. I think what happened here is that the graph is really made by depth along an ice core (which starts at 0). In order to make the graph more interesting they converted depth to "years ago".

I'm pretty sure the X Axis is the year.. meaning to the right is historical data and to the left is the most recent. Its a little weird but it kind of makes sense.

not a Danish thing, perhaps it's because it's just a plotter so it starts printing the first year and then goes back?