We're not quite sure about carbon neutral schemes.
These are usually schemes which allow us all to offset our carbon emissions by, for example, paying someone to plant trees. However, not emitting the CO2 in the first place is a more environmentally efficient way of leaving no trace.
Another issue that has been raised is that certain schemes are 'for profit'. Which means that resources are being directed away from environmental protection.
If you wish to read more about this debate, see:
http://www.off-grid.net/index.php?p=365
http://environment.guardian.co.uk/climatechange/story/0,,1889791,00.html
Some sites we'd like to recommend are:
http://www.woodland-trust.org.uk/carbon - A recognised UK charity.
www.climatecare.org - As recommended by 'Best Foot Forward'