I'm in my 50's... and I remember filthy air you could barely breath and horribly polluted rivers that caught on fire. I remember people tossing trash on the side of the road without regard. I remember trash floating in our lakes, which were so filthy you were scared to let the water touch you, much less eat the fish (if any) in them. I remember when all cars belched clouds of black smoke. I remember national parks with no wolves and no bears.

Today, the skies and rivers are noticeably cleaner. There seem to be more large wild animals (wolves, bears, buffalo, cougars, elk) in national parks and forests now than when I was a kid. And you can eat the fish in the Great Lakes now. Wild deer are, seemingly, everywhere around here and rise to nuisance levels. On the other hand, there seem to be less earthworms in suburban areas, somewhat less bugs and less birds. But that may just be related to where I now live (a much more urbanized area than that of my youth). Or it may be a harbinger of doom. I don't know.

Of course, my perspective on this is rather limited since I can only say what I've seen. Larger wild animal populations in Western Europe, for example, are essentially non-existent in comparison North America. I suspect that most or all of the decline described in the report happened in what were pretty poor regions of the world 50 years ago. But now that some of those nations are approaching the levels of wealth where they can start to care, I'm confident they'll start to clean things up over the next half century like most of the developed world did over the last half century.