CAMBRIDGE, England -- As I write, the world's leaders, well most of them -- U.S. President George W. Bush is too busy clearing his desk after a month's holiday -- are lining up to make their speeches at the Johannesburg global conference on sustainable development.

They will all be very predictable, as will the final communique. This will "commit" the governments of the participants to all sorts of targeted actions to change the world for the better. Well, almost. There will be a lot of weasel phrases like "as far as possible" and "were feasible." Some are already in place, for example, in the section on protecting diminishing fisheries.

Junkets such as the Johannesburg conference cost a lot of money. Bringing together 65,000 delegates from around the world and keeping them in town for two weeks cannot have cost less than a quarter of a billion dollars. However, they rarely achieve anything of lasting significance, except an overwhelming sense of self-importance among the official delegates and nongovernment organization representatives.