LONDON - Government officials and activists flying to Bali, Indonesia, for the United Nations meeting on climate change will cause as much pollution as 20,000 cars in a year.

The delegates each will produce an average 4.07 metric tons of carbon dioxide, or CO2, to reach the resort island 950 kilometers (600 miles) from Jakarta, according to estimates e-mailed to Bloomberg by the UN agency holding the conference.

Some of the 187 nations participating in the two-week forum promised to offset their so-called carbon footprint by planting trees or buying emission credits. The symbolic actions will not help stop global warming, scientists say.

"It's very hard for the public to understand that you come together with so many people to a very distant place and cause a lot of emissions, and at the same time talk about emission reductions," Artur Runge-Metzger, head of climate strategy for the European Commission, said yesterday in an interview in Bali.

Carbon dioxide is responsible for the higher temperatures that are causing a surge in sea levels and an increased risk of droughts and floods, according to UN reports. The goal of the Bali meeting is a deadline for a new international treaty to limit emissions after the current accord, called the Kyoto Protocols, expires in 2012.

The UN Framework Convention on Climate Change, the conference organiser, failed to get some governments to fund clean-energy projects or plant trees to offset the emissions, said Yvo de Boer, executive secretary of the convention. Some of the 10,000 attendees to the meeting, held in air-conditioned rooms at the tropical beach resort, planned their own projects.

Indonesia will plant 79 million trees, Emil Salim, head of the host country's delegation, told reporters on Tuesday in Bali. The Asian nation is investigating how to develop its tree- planting activity to ensure a lasting offset, said Amanda Katili, special assistant to Environment Minister Rachmat Witoelar. "We have to know where the trees will be planted and make sure that they grow and not be cut down until they make enough carbon stock," Ms. Katili said in an interview.

The UK's 40-person team will have their emissions neutralised through a central government fund, a spokeswoman for the country's environment department said.

EU Environment Commissioner Stavros Dimas and three of his staff are buying so-called carbon credits, each representing a reduction of a ton of carbon dioxide, on the EU Emissions Trading Scheme, commission spokeswoman Barbara Helfferich said in a telephone interview. "I'm paying out of my own pocket, and some individuals will also offset," said Ms. Helfferich, adding she's spending about 90 euros ($132).

The US will not compensate for the emissions of its delegates because "we feel the best use of taxpayer dollars is for technology advancement, not purchasing carbon offsets," said Kristen Hellmer, a spokeswoman for the delegation.

The total of 40,700 tons of gas created by the conference is equivalent to the annual emissions of 20,350 mid-sized cars, each traveling 12,000 kilometres, according to www.atmosfair.de, a website that allows air travelers to compensate for emissions by investing in strategies to cut gas output in countries like India.