Acid rain in western Europe is on its way to the history books; the gaping hole in the earth's protective ozone layer is said to be under repair because of international agreement on phasing out CFCs. Some of the previously most dirty rivers are becoming cleaner (at least as far as some pollutants are concerned). Some of the most toxic pesticides have been phased out in western countries. Our cars are now individually less polluting. And around twelve percent of the earth's land area is now protected in some way for conservation purposes.
Source: Juniper, Tony, "Big Picture, Small Planet," Resurgence, No. 221, November/December 2003, 11