The conference will have about 12,000 participants from 189 countries, and since Bali is in the middle of nowhere we can assume that the average participant flies 1/4ths of the Earth's circumference to attend, or about 6,000 miles.
Passenger air travel costs 0.18 kg CO2/passenger-mile, for long-distance flights. Of course, many participants will be taking private jets, which will throw this calculation way off.
So the total carbon emissions for travel to-and-from the conference are 26 MMT CO2 (million metric tons).
The average American emitted 24.1 MT CO2 in 2006, so travel to-and-from the Bali conference is equivalent to 1.1 M American-years of carbon expenditure. Or about what the city of Portland, Oregon spends in two years.
Of course, Americans are energy pigs. Worldwide carbon expenditures in 2006 were roughly 20,000 Tg CO2 (=20,000 MMT CO2), for 6.3 B people. So
This is just for travel, and does not include travel on private jets, which is likely to be large.
Per-day costs for food, lodging, etc. are assumed here to be the same, as many of these dignitaries no doubt live the high-life, just as they would in a first-class hotel in Bali.
As some people have said, I'll start thinking global warming is a crisis when the people telling me it's a crisis act like it's a crisis. You have to wonder where the Bali participants are coming from.
Note: Correction here.