But even these and other thoughtful tricks to scale back greenhouse gas emissions will not help the December 3-14 marathon on climate change avoid a horrible fact: it's going to generate carbon. Lots of it.

According to the organisers, the UN Framework Convention on Climate Change (UNFCCC) talks on the Indonesian resort island of Bali will result in an average "carbon footprint" of 4.7 tonnes per person of carbon dioxide (CO2), the principal greenhouse gas.

If 10,000 delegates, campaigners and journalists attend the conference, the footprint will be around 47,000 tonnes of CO2, including travel to and from the event and activities during it.

Using an online calculator on the websites of (www.carboncalculator.co.uk) and (www.atmosfair.de), that works out to the equivalent emissions from driving 100,000 cars up to 3,300 kilometres (2,062 miles each) each.

The figure is very big, mainly because of the use of fossil-fuel-thirsty air travel to haul participants from distant North America and Europe.

Then there is the voracious energy cost of cooling the sprawling conference facilities -- clustered in several hotels in the town of Nusa Dua -- to filter out Bali's sultry tropical heat.

"This conference is causing a lot of CO2 emissions. I hope that at the end of the day, it will deliver an agreement that will reduce even more CO2 emissions," UNFCCC Executive Secretary Yvo de Boer told AFP last week.

Greenhouse gases principally come from burning oil, gas and coal, the main energy source for the world economy today.

These emissions hang in the atmosphere like an invisible shroud, trapping solar heat instead of letting it radiate safely back into space.

The Bali talks -- taking place against a background of dire scientific warnings on the amplifying consequences of climate change -- are aimed at setting down a negotiating strategy to conclude a new pact for curbing this pollution.

Faced with the guilty awareness that they are fuelling a problem they are supposed to be solving, some governments, UN agencies and non-governmental organisations (NGOs) are turning to carbon "offsets" to diminish their footprints.

Under offsets, a polluter can invest in projects that will reduce his CO2 pollution elsewhere by an equivalent amount.

Indonesia, for one, has vowed to plant 79 million trees that, by growing, will soak up CO2, to help compensate for the pollution engendered by the UNFCCC meet.

Greenpeace says it buys "gold-standard offsets" -- offsets that are certified by experts as having a genuinely compensatory effect, an important point in the voluntary and unregulated offset business.

It also buys renewable energy credits to help counter-balance the CO2 emissions caused by bringing its team to Bali.

"We have to be here, we have to be doing what we can to solve climate change and that means going where the decisions are made and the decisions are being made here," a Greenpeace spokesman John Coequyt said.

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