We're destroying our environment through industrial by-products, deforestation, etc, and when the possibly biggest side-effect of all this planetary abuse starts being obvious, we only talk about that, and make it the only metric.
Getting people to care about the environment is something possible, as other generations have done this better. It only if all your education of the general public and legislation starts from the premise that we need to keep the health of the entire world, in all aspects.
Single metric carbon-tax is easily gamed by corporations and makes the general public apathetic. Maybe that's the goal for some lobbyists, but that's the battle from my point of view.