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.

So, what we do as individuals matters. It adds up.

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.

We may get to the point where the only way of saving the world will be for industrial civilization to collapse.

I am President of the UN created University for Peace, which has a strong commitment to the relationship between peace, security and the environment. I meet with young people around the world and I always come away enthused and encouraged.

If you want to maintain a sustainable supply of fish you have to farm the fish, rather than mine them. So putting your money into fishing fleets that are going to exacerbate the problem by over-fishing is not the way to preserve the underlying asset.

I am convinced the prophets of doom have to be taken seriously.