Those firms who do select the city can work with the hotels to ensure that they offer the right environmental approach, such as the use of laundry water-saving programmes, says Katz. "You can also work with the convention centres to reduce the lights, power, and HVAC used during the move-in and move-out times in the convention halls," she adds.

The other thing in Vegas's favour is that the strip, where almost all the conventions happen, is compact and easy to walk to. That's an important point when considering transportation, which according to Sarah Webb, campus sustainability co-ordinator at the University of Victoria, should be a key concern for any event.

"You should look at your venue, and find out how accessible it is to public transit?" says Webb, who explains that the University has its own guidelines for organising green events. "Do they have bicycle parking available? When you're inviting people, you should let them know about those options." It's also useful to provide incentives, she says. Reimbursing public transport costs, or entering the names of car poolers into a prize draw, can all help to improve attitudes to travel.

Food for Thought

Food and beverages are another important area to consider, says Webb. "For example, here in Victoria, we have some of the best water quality. There's no need to order bottled water. Jugs of water are just fine," she says.

It's also important to think about the total life cycle of the products and services being used for a green conference. For example, Webb advises trying to source food from local suppliers when organising an event to reduce the amount of carbon burned during transport. Similarly, McAfee thought about where the l eft over food was going after meals. "We ensured that the hotel had a food donation program so that waste food could be used," Sabo says.

The fundamental question for anyone planning a more sustainable event is how much of a trade-off do you want to make between the time invested in greening an event, and the resulting impact reduction? McAfee seems to have missed the mark in some areas. For example, it used compostible, corn starch-based cups for its drinks at the sales event. But did it take advantage of that when disposing of them? "They went into the normal waste cycle," admits Sabo. His protests that the cups will at least biodegrade in the landfill seem weak.

Other waste reduction options include digitising literature so that it is available online, rather than handing it out on paper, says Webb. Such measures may only save minimal amounts of waste in the context of the whole event, but each small action adds up.

But there are some environmental impacts that are difficult to alleviate. Nine tenths of the carbon emissions at McAfee's event came from air travel. People flew from across the world, and Sabo says that no one city stood out as being closest to a larger number of delegates. Some companies may be able to choose their locations wisely based on their attendees' place of origin, but for many, the only real option will be to pay for offset credits to try and get the carbon off their conscience -- or not hold the event at all.