ATBC members voted at the ATBC Morelia 2007 meeting that their meetings should be carbon neutral, through providing a fee dedicated to supporting regional forest restoration and / or conservation projects. However, this resolution has not been applied at all subsequent meetings. After the Merida meeting, the delegates of future ATBC meetings will be encouraged to contribute with mandatory fees to offset carbon emissions. In Merida, the contribution will be voluntary and the contribution fees have been established based on a carbon emission analysis (including the projected energy expenditure during the meeting, as well as the emissions due to travel of delegates). The Edinburgh Centre for Carbon Management Ltd (http://www.eccm.uk.com/) carried out this analysis for the Morelia meeting. For the Merida meeting, we will have very similar carbon emissions to the ones we had in Morelia. The carbon-offset fee will be US $ 20 for delegates coming from outside Mexico and US $ 5 for people coming within this country. The money collected will be allocated to an inter-municipal project in Yucatán managed by the civil organization JIBIOPUUC that, among several communal activities, is dedicated to conserving and restoring the largest tract of old-growth tropical forest remaining in the center of the Yucatan Peninsula.