Why are we all haunted by dinosaurs? It can't be just because we keep electing them. Children like dinosaurs because they were vast, terrifying and are mercifully extinct.
Their scale makes them threatening but their fate suggests a final fragility. So their size, more poignant than frightening, becomes a reminder of the vanity of the mighty. The lesson for children can be reassuring - smaller things survive, if they are patient enough, to inherit the Earth.
For adults, the moral may be more frightening. Sheer size led to the dinosaurs' undoing - they got so large that they consumed the entire eco-systems which sustained them. Like a certain mammal may be doing right now?
Not long before he died, Pope John Paul II likened western man to a person who saws off the very tree-branch on which he is sitting. That wasn't just a lament for the repudiation of the wisdom of centuries by shallow modernisers; it was a specific reference to the pointless destruction of nature itself.
Slowly but unavoidably, the environment is becoming a pressing political concern. For the past century, elections have been fought over five-year plans, but voters across the Northern Hemisphere are now beginning to think in terms of ecological time.
The days when George Bush snr could say that trees caused more pollution than oil rigs are gone.
The leaders of Fianna Fáil have wised up. Their recent think-in in Co Mayo - the home of the Rossport controversy - took the environment as its theme.
For the young couples who are the "swing factor" in the coming election, the environment is a real concern, because the toddlers they strap into cars will still be around near the century's end.
Yet many of our centre-right politicians try to portray the Greens as nutty radicals. The truth is, of course, that conservation and conservatism might go hand in hand. After all, traditional Christians - like believers in most of the great religions - see the world as given in a sacred trust.
Whether people believe in an afterlife or not, one thing is sure: they do not just inherit the Earth from their parents - they also borrow it from their children.
In the coming century, if present trends continue, more than 5,000 languages will die out, as also will more than half of the animal species.
The constant burning of forests will unleash gases which could irreversibly alter our climates.
Freedom from poverty was once enough for most people, but it has been replaced by a notion of freedom as the unconditional right to consume - consume fish stocks, species, trees.
Before it is too late we need to figure out a comfortable way of living which does not destroy other forms of planetary life. In effect, mankind must reapply for readmission to the eco-system.Religious believers might be expected to sanction the notion that all that lives is holy.
The destruction of an environment which they believe is God-given is down to many of the deadly sins that they, too, would excoriate - the pride that leads humans to assert primacy over nature rather than parity with it; the covetousness of unbridled consumerism; anger at the power and mystery of nature; gluttony for more food than any person could ever need; and sheer laziness about seeking alternative ways of finding happiness.
Ever since the Nazi horror, those who link spiritual values to political campaigns have had a hostile press. This is one reason why the Green parties are not even stronger in Europe. In the US, ecologists are weak because of the old puritan settler distrust of nature as eternal enemy.
Here in Ireland, however, the health threats posed by nuclear waste in the Irish Sea and by chemicals in foods will be key factors in the next election.
John Paul II said that nature had been provoked into rebellion by a humanity which presumed to play God. Nature, in that analysis, was like an unhappy colony, oppressed rather than justly administered.
Most of the blame for this state of things lies not with the world's poor, but with that section of it which is affluent and addicted to over-consumption.
It isn't just a loss of respect for the sacredness of life that has led to this crisis. It's also a decline in man's historical sense - a failure, despite the lessons of Darwin, to think in anything more than the selfish short term.
"In the long run," said a famous economist, "we are all dead." But nature doesn't work like economics. If we steal precious resources from our grandchildren, they may never get them back.