To be sure, Sir David Attenborough is a Gaian Bodhisattva (the highest praise I have for anyone). But sadly, as Bob Dylan once observed, "Most people don't do what they believe in; they just do what's most convenient and then they repent."

The reason for this is simple: we are animals. Watch any cat find the warmest, sunniest spot in the house during the winter--or if it is cloudy, they'll curl up next to a heater, with no thought whatsoever for whether the source of that heat contributes to CO2 emissions.

And deep down, we're no different. Like every other animal, we seek the path of least resistance, regardless of what we know or believe about the wider world. If it is too far to walk or we are in a hurry, we drive--regardless of our keen awareness of the utterly destructive consequences of automobile culture on our communities, environment, and planet. To do otherwise is to swim against the current, not only of our industrial civilization, but of our own bodies (which likewise innately seek the path of least resistance to conserve our energy reserves). Indeed, Dylan's observation could be the epitaph of humanity.

But guilt tripping people does no good whatsoever. All we can do is, in our own ways, strive to make it more convenient for ourselves, our neighbors, and others to do the right thing. Grow gardens, grow community, grow awareness.