How do the certificates work?
The amount of CO^₂ and other greenhouse gases produced by your flight travel can be worked out via the Trees for Travel website (www.treesfortravel.nl). The calculation depends on the flight destination and the number of passengers; the further you fly, the more CO^₂ you produce and, therefore, the more you have to offset. The results from the calculations have been averaged so that the destinations can be divided into three zones:

• Zone 1:
  flights within Europe (including all Mediterranean countries)
• Zone 2:
  flights to the Middle-East, Africa , North and Central America
• Zone 3:
  flights to the Far East, Australasia and South America

The certificates can be purchased via the website but also via an increasing number of travel organisations.