The world over; humanity has put more carbon into the air by weight than the total sum of all that we've built on the surface, and it's still accelerating. It's a rather awesome testament to humanity, but not exactly in the positive sense given that the externalities are beginning to bite.
Here's a link to global CO2 levels [0]. As I understand it, it's live data from satellites.
You can see it's lower (redder) where forests and plankton are growing, and higher (whiter) elsewhere. You'll also notice that it's pretty much the same everywhere - the range is only 400 - 450 ppm.
