By Alex Kirby BBC News Online environment correspondent

The World Summit on Sustainable Development in Johannesburg is being followed by Alex Kirby for BBC News Online. In the second of his reports he notes that there is little to stop protesters stepping in to set the agenda.

There is a strange feeling in Johannesburg at the moment, with nobody quite sure what to expect as the sustainable development summit finally lumbers into formal life.

It must be one of the oddest conferences I've ever covered.

Protesters are happy to fill the official vacuum with their answer to the global economy - and that answer involves business going a lot further than it already has to reduce its impact on nature

Partly that's because of what is on the agenda, and partly it's on account of what doesn't figure there.

First, let's take the probable glaring omission.

There is no big headline-grabbing agreement or convention up for signature here.

It looks at the moment as if the best anyone can hope for is a fairly milk-and-water statement exhorting us all to do more about poverty.

So that leaves a vacuum, inviting anyone to step in.

Focus of protest

Enter one key agenda item, which looks likely to get more of an airing on the streets than in the conference centre: globalisation.

It is down for discussion, but you'd be hard put to find anyone who expects radical decisions from the conference here - or any decisions, probably - on making industries that span continents answer to national governments.

That doesn't mean globalisation will go unnoticed, though.

It has already been the focus of protest, and it looks set to bring more protesters out, conscious of the chain they see linking Seattle, Gothenburg, Genoa - and now Johannesburg.

The rainbow nation is turning grey around the edges, and many of us are not quite sure what to hope for any more

They are happy to fill the official vacuum with their answer to the global economy. And that answer involves business going a lot further than it already has - or perhaps can, if we want to go on living the lives we do - to reduce its impact on nature.

On Saturday I met two police officers in a lift, both enjoying ice-creams. When I said they seemed very relaxed, one replied that it was going to be a quiet and peaceful summit.

Two hours later his colleagues were firing stun grenades at protestors a few miles away.

On Sunday even the police horses were picking their way round the conference centre complete with protective headgear.

Faded hopes

Another presence is also waiting in the summit's wings - Zimbabwe's President Robert Mugabe. How much attention he may get, and what influence he may have on the agenda, no-one can yet say.

But many South Africans are dismayed at the turn events have taken across their northern frontier, so Zimbabwe will be hard to ignore.

Perhaps the biggest difference between the 1992 Rio earth summit and the Johannesburg 2002 development summit is the withering of hope.

Then the fall of the Berlin Wall and the overnight evaporation of the Cold War were recent memories.

The day was discernibly close when the last apartheid President, F W de Klerk, would hand power to Nelson Mandela in a speech which he ended with the words of the new South African national anthem - Nkosi Sikeleli Afrika, God Bless Africa.

Now, though, new enemies have been defined.

Now the rainbow nation is turning grey around the edges. And many of us are not quite sure what to hope for any more.