This bug is actually in my TE nation but I've observed the same bug in CN:SE, I just haven't reported it until now.
A few days ago I got the drought event and choose the -10% land option. As expected my land area decreased however, my citizen count didn't drop as it should have. Today my environment mysteriously dropped by one point. I was close to the 1:2 land:infra ratio after a few battles but hadn't hit it yet, however, removing the -10% land penalty would've put me just over it, explaining the extra env point. Buying enough infra to push my pre-10% land:infra ratio back under 1:2 did indeed increase my environment by 1 point.
I hate to look a gift horse in the mouth here, but it appears the land events aren't being taken into account everywhere.