We owe at least this much to future generations, from whom we have borrowed a fragile planet called Earth.

Ted Turner is still a leader. And he sets a great example. His ability financially has been reduced, but his influence and his example still is an important asset to the whole environmental movement.

The concept of national sovereignty has been an immutable, indeed sacred, principle of international relations. It is a principle which will yield only slowly and reluctantly to the new imperatives of global environmental cooperation. It is simply not feasible for sovereignty to be exercised unilaterally by individual nation states, however powerful. The global community must be assured of environmental security.

Inertia is a powerful force in human and political affairs.

Nevertheless, the concept of sustainable development is now known - even amongst those who haven't accepted it - and it's recognized, debated and followed by an increasing number of businesses.

Not to say that corporations are perfect today, but even grand corporations like Dupont have made immense progress in translating some of their past environmentally damaging practices into new profit opportunities.

After all, sustainability means running the global environment - Earth Inc. - like a corporation: with depreciation, amortization and maintenance accounts. In other words, keeping the asset whole, rather than undermining your natural capital.