When I close my eyes at night, no matter where I am, my mind often drifts back many years to the newly commissioned Calypso floating beneath a Mediterranean sky. The ship was my childhood home, though I never had a place reserved to me. Instead, I slept in a different bunk each night, sometimes in the open drawer of a locker, sometimes in my mother's bed, sometimes in my father's. Calypso was my childhood identity.

I was lucky. My father's ship was my foundation, the beginning of my future. As Calypso sailed the world, she came to embrace the philosophy that life on our planet is fragile and that its beauty, though ancient, is perishable.

My father imparted to me the belief that we are not owners of the world's resources, but its stewards. We are responsible for protecting what we have for those who will follow.

Today I try to live by that compass, but as I travel I am struck by how infrequently adults keep future generations in mind. Across the globe, we see parents who seem to care little about the condition of the planet their children will inherit.

We pollute the rivers and aquifers that will be our children's source of fresh water. We tamper with the ozone layer that would protect our children from dangerous solar rays, putting our children at risk of drought and disaster. Unborn children cannot speak out. Nonetheless, we are accountable, even to generations we will not see.

As far as I know, none of the most powerful nations on earth has legal responsibility to protect the environment for future generations. But interestingly, the tiny island nation of Papua New Guinea has made such an attempt, having written its concern for its children into its very constitution. It states: "We declare our natural resources and environment to be for the collective benefit of us all and to be replenished for the benefit of future generations." Each citizen is expected to behave with future citizens in mind.

But words alone cannot prevent the greedy from preying on the unsuspecting. Resource exploitation means quick money, and quick money is blind to tomorrow.

Witness the now classic tale of Wezip Alolum, which has to do, quite simply, with mud. Wezip Alolum, a member of Jobto village in the Papua province of Madang, owned forested land on which was a mudpit. For generations, his family earned its living by exchanging balls of mud and mudclay pots for food. The mudpit had been his inheritance, passed on to him intact by his ancestors.

When foreign developers sought permission to log on the family land, Wezip Alolum was reluctant. "You won't need mud anymore," he was told, "now you will have money." He finally agreed.

However, he had not understood that the company intended to fell or burn every tree, leaving none to reseed. It was beyond him that the company would treat the land without respect for its future. Soon not only were the trees gone, but with the resulting erosion, even the mudpit was spoiled. Its clay was ruined, too dry to work. Wezip Alolum also soon ran out of money. Without mud, for the first time in the history of his family he was poor.

He demanded that the forestry company reimburse him for his loss of the pit. But who would pay compensation for mud? Yet to Wezip Alolum the mudpit amounted to inherited capital from those who came before him. He had been both owner and caretaker. Now he had nothing to leave his children.

Wezip Alolum was a victim of a shortsighted exchange of resources for cash.

But what of us? In squandering natural resources, are we not behaving recklessly toward our children? When they realize we have bequeathed them a host of environmental perils, a greatly depleted inventory of resources, what will they think of us, despite our drive to buy them the best we can afford?

Calypso was more than a boyhood gift. She remains a legacy to me, a reminder of continuity and the ideal of inheritance combined with responsibility. She is a living document, my constitution for tomorrow.

Perhaps, if we change our ways, a global constitution will someday protect our air, water, forests and wildlife - our natural legacy - for future generations. Perhaps our children will write it.