Are you, or those that have this fear, concerned enough to actually alter your/their behaviors?
Yes, I have changed the way I do things. I walk and bike a lot more, use public transit when available even if it means my trip to wherever is going to take longer, and lower the temperature in my home in favour of putting on a sweater. A small contribution on its own, but the cumulative effect can be considerable if more take the same steps, and it beats doing nothing. Still, without the active participation of the corporate and public sectors individual efforts can easily be negated.