Firms hosting green events were given a stark reminder of the need to minimise the environmental impact of their attendees this week after delegates at two African conferences on climate change were slammed for failing to offset their carbon emissions.

According to reports in the Daily Telegraph, a straw poll of 29 participants at a 140-strong conference in Kenya organised by the European Parliamentarians for Africa (Awepa) group found only one had offset the emissions from his flight.

"Whether or not to fly carbon neutral was a decision which was left up to each of the delegates themselves," Femke Brouwer at Awepa told the paper. "I think you will find that the vast majority will not have [paid], but we at Awepa are developing a policy which will allow our members to fly carbon neutral, which will be in place for the next meeting early next year."

The paper also revealed that delegates at the UN climate change conference in Accra, Ghana, this week had not been obliged to offset their carbon emissions.

A spokeswoman for the UN said that it was aiming to introduce a scheme that would ensure that all its climate change conferences are carbon neutral, but currently the decision on whether to pay for carbon offsets is left to individual attendees. She added that there was no set date for the introduction of the UN's own offsetting scheme.

Susan Gurley, executive director of the Association of Corporate Travel Executives, said the news highlighted the extent to which those firms that do not undertake efforts to minimise the environmental impact of conferences are undertaking significant reputational risks.

"Ofsetting is becoming standard for events now," she said. "Some people might criticise it, but until something better comes along it is the best tool we have and conference organisers should embrace it."

Bill Sneyd, director of advisory services at offsetting provider the CarbonNeutral Company, agreed that green events were increasingly embracing offsetting, although he admitted it was often harder for inter-governmental conferences to embrace offsetting as such a move would require the support of all attendees.

"As a minimum, event organisers should make it easy for participants to offset if they want to," he said. "You can have a debate over whether the host should pick up the bill or whether it is better to let people to make a decision themselves, but the option should be there."