Earth Summit

What is it?

The summit is organised by the UN and will run for 10 days until September 4. Currently 174 countries are expected to attend. There will be 106 heads of government from those countries present, including the prime minister, Tony Blair, but the presence of the US president, George Bush, has not been confirmed. The summit has been billed as the biggest UN convention ever held.

The organisers say the aim is to meet "difficult challenges, including improving people's lives and conserving our natural resources in a world that is growing in population, with ever-increasing demands for food, water, shelter, sanitation, energy, health services and economic security".

The goal is to come up with concrete action plans to reduce global poverty and the poverty gap in a "sustainable" way, that is, without inflicting irreparable damage upon the environment.

Why now?

It is 10 years since the 1992 Earth summit in Rio, where the international community adopted Agenda 21, a global plan of action for sustainable development. This year's summit is designed to shore up and expand on that accord.

Local authorities in Britain have adopted Agenda 21 policies with varying success.

Will it do any good?

The Guardian's environment correspondent, Paul Brown, reported that the conference is seen by many as a talking shop and too unwieldy to produce concrete results. Hundreds of delegates will be there lobbying from groups as diverse as bird-watchers and the oil industry.

Twenty UN bodies will be represented, and an environment conference is running in parallel.

Gordon Brown argues that, since Rio, the "aims of environment and development groups have got much closer". He says that the conference is taking place against a backdrop of famine in southern Africa, caused partly by climate change, which is reducing rainfall, and a lack of clean water and sanitation.

What will top the agenda?

The summit's primary concerns will be the failure to reach many of the UN's development targets and to reduce world poverty.

At the end of the summit it is hoped that the world leaders will sign a declaration designed to set new targets on poverty and development, but most observers are saying this is likely to be so bland that it will not amount to any real commitment to progress.

Developing nations want more aid, building on modest commitments they gained at Rio, with some asking for more money to protect the environment. The developing countries also want greater trade liberalisation, especially in agriculture where many of the rich northern hemisphere countries impose massive tariffs. But the rich countries want liberalisation in other markets - in electronic goods and services, for example - and will try to push these on to developing countries.

Where does the US fit into this?

Some critics argue that the Bush administration is the main obstacle to worthwhile progress. Mr Bush himself is lambasted in some quarters as being a long-time opponent of environmentalism. Mr Brown says that the US has been seen as an "environmental pariah" after Mr Bush pulled out of the Kyoto agreement.

At preparatory meetings before the summit, the US delegation, numbering more than 130, has been accused by environment groups of obstructing any attempts to impose new targets and timetables on relieving poverty and promoting development.

Will there be high security?

Indeed. With so many delegates, Johannesburg will be turned into a mini-fortress protected by some 27,000 police officers.

It sounds spectacularly expensive. Are politicians fearful of claims that it is a luxurious junket?

Very. The Guardian reported that the government was cutting its delegation down from 100 to 70 after concerns about junketeering accusations. It was claimed that the environment minister, Michael Meacher, was among those who had been sacrificed.

The environment group Friends of the Earth then said it would pay for him to go as he was the only government minister sufficiently well versed in environmental issues. Several days later the government announced that its delegation would include Mr Meacher, claiming it had never finally decided who was going.

The UN has warned its managers about enjoying lavish entertainment at a time when southern Africa is under the threat of famine.