It's being done in Europe since decades actually and probably in other places. Not sure though whether the figures are true, and or how they are calculated. But I'd say slowly Europe is getting there.

article Washington Post 2014

Forest and nature destruction, started actually thousands of years ago What has changed though the last couple hundreds years is an extreem population boom.

The first polluted river in the world is like 5000 yo or something.

Ad. just saw someone else saying reforestation even started 100s of years ago. Though reforestation to me, also means more net green.