Offset your flights

Does planting trees help?

16.12.2005 This is a contraversial area, both because of the underlying science and because of practical issues of whether there is enough land, whether new trees are actually being planted and whether they are being maintained.

How does it work?: forests take up CO2 from the atmosphere and store it as biomass. Some carbon may be locked-up for the long-term in roots and soils and some is released when trees are harvested. Forestry offsets are normally based on estimates of the long-term carbon storage, taking into account uptake and releases.

Strengths: probably the most practical way of taking carbon out of the atmosphere. Forests are an important part of the global carbon cycle; globally they absorb about 25% fossil fuel emissions on an annual basis. Forests also provide many other important benefits, such as timber, fuelwood, watershed protection and biodiversity. Forestry projects are popular for small-scale offset initiatives because they are readily scaleable.

Weaknesses: strengthening the carbon sinks does not address the main problem of climate change that is mainly caused by fossil fuels. Carbon uptake may be reversed if forests are cut down; while the risks of reversal can be minimised through careful management it is not possible to provide an absolute guarantee of permanent effect.

Take care: use projects that have been independently checked; that have been carefully designed taking into account of local conditions. Try to ensure that the project provides local benefits. Avoid free-riders such as conventional commercial forestry plantations.

Key Travel (who offered the advice above) links its flight bookings for charities directly into the Edinburgh Centre for Carbon Management. They in turn arrange for appropriate numbers of trees (that you pay for) to be planted and maintained in Mexico, Mozambique, Uganda and India. The price per tonne is extremely reasonable at £4.50. This seems to make it almost too easy to offset one's flights - indeed one's whole lifestyle - for very little money. But this is where the other arguments kick in - there isn't enough land to make this more than a very partial solution.

Another commercial company offering an offset scheme with British forests is The CarbonNeutral Company. Formerly known as Future Forests, they seem to be more gift-oriented and charge around £15 per tonne (£10 per tree), working with four forest managment schemes in the UK.

There are also other ways of offsetting your flights - check out Key Travel's advice.