On Friday, the inhabitants of Beijing woke up to see, or rather not to see, their city cloaked in a thick cloud of smog. Children and the elderly were advised to stay inside. The government's top weather expert warned they were at most risk of contracting respiratory diseases. He told people to wear a face mask if they had to leave the house.

The state news agency Xinhua said a heavy fog had enveloped the city and trapped the pollution. It reported that most highways leading into the capital were closed because visibility had been reduced to fifty metres in some areas.

As proof of the city's environmental problems, the timing could not have been better. On Thursday, the president of the International Olympic Committee, Jacques Rogge, warned a major environmental forum in the city that events at next year's Games could be delayed because of pollution.

Threat to sport

Rogge even questioned the future of sport in general, warning that the "fragile condition of the environment posed a direct threat". He concluded pessimistically that "global warming will jeopardise sports in the long term and the very existence of winter sports in many areas of the world."

Global warming was also high on the agenda this week in Indonesia where environment ministers and officials from about forty countries met ahead of the Bali climate change conference in December.

The December meeting is due to hammer out an agreement to curb carbon emissions after the Kyoto Protocol expires in 2012. Indonesian president Susilo Bambang Yudhoyono said it was logical that developed countries take the lead in reducing carbon emissions but added that "developing countries, on the other hand, should participate voluntarily in reducing their national greenhouse gas emissions according to their national circumstances."

"Many developing nations are already promoting and implementing measures to reduce emissions as well as to adapt to and cope with the impact of climate change. Nevertheless, the situation calls on the developing nations to do more," he urged.

Action today, not tomorrow or in future

That the situation is crucial and needs immediate attention was also made frighteningly clear by a report published on Thursday. In its "Global Environment Outlook" report, prepared by almost four hundred experts, the UN Environment Programme deplored the fact that most nations still fail to recognise the urgency of the environmental challenges faced by the planet.

The Executive Director Achim Steiner said the "depressing conclusion" was that the situation was worse than twenty years ago and going downhill in many critical areas, especially water.

The report concluded that the common future of the planet depends on "actions today -- not tomorrow or some time in the future".

If the world's inhabitants are to have access to clean water in future, and the citizens of major cities, not only Beijing, are to walk around safely without having to wear face masks, climate experts recommend that developed and developing nations come together fast to find an acceptable and appropriate way of tackling global warming before it is too late.