I come into contact with environmental activists pretty often. I've been at hearings where 10 people in the audience are wearing gas masks. I've been in stake holder's meetings where the debate got so shrill that meeting was adjourned.
Environmentalists lost their focus somewhere around 1980. Prior to that, ranchers, farmers, hunters, etc. often worked closely with environmentalists. Their "reality-based" support dropped out when extremists offered a vision of zero human impacts - an impossible goal.
When those extremists teamed up with PETA, Greenpeace, Earth First, ELF and others, the cause was lost. People do believe that children have more value than a dog. People won't pay to support a habitat they are forbidden to enter. People really don't want a third world lifestyle.
And by the way - the air is cleaner now than at any time since the industrial revolution. In the big cities it may be cleaner now than ever PERIOD.
But, as you know, that's still not enough to make them happy!
They won't be happy till the air and water is STERILE!!!
(and then they'll bich because that's not healthy)