How do airlines calculate carbon credits? Which offset programme should I support?

Carbon schemes are something more travellers should be asking about and take control over. Photo / Getty Images

Thomas Bywater answers your travel questions

I was comparing flights back from Christchurch to Auckland when I found something unusual. Jetstar and Air New Zealand seemed to offer almost identical fares in departure date and flight times. For a small fee, both flights also offered the option to offset carbon emissions.
However, Air NZ's offset fee ($2.58) was over three times more expensive than Jetstar's ($0.87). Can their planes really be that much more efficient?
How do airlines calculate carbon credits? And where does the money go?
Linda

While carbon offsetting is a hot topic it's refreshing to have a reader question where their credits go. It's something more travellers should be asking and taking control of.

Both airlines operate A320 aircraft on the route, and while Jetstar carries a few more seats (around 186 to Air NZ's 170) on paper it's a fairly similar flight.

A less charitable flyer might assume the costs are plucked out of thin air.

Like modern day penance, conscientious passengers are being asked to pay for air travel absolution.

Tick the box. Count a rosary. Ascend into the heavens on your A320 guilt free.

However carbon offsetting is often quite literally a question of faith. Firstly that what you pay equates to what you're producing. Secondly that enough passengers will "opt in" to make it effective.

Airlines buy carbon credits from projects that take carbon out of the atmosphere, offsetting one of the main jetfuel pollutants. A Koyoto credit is equivalent to one tonne of carbon but the cost of a credit can fluctuate wildly.

The ICAO calculates the emissions of your journey from Christchurch to Auckland at around 4.3 tonnes of carbon, or roughly 42 sacks of coal.

24kg of said lumps of coal are yours to get rid of. But how?

Credits can be bought from any number of clean energy or reforestation projects.

In theory you could pay an army of carbon-accredited bonzi gardeners to offset your emissions, however this would be very costly.

"The key thing that drives cost is the scale of the scheme and where it's located as well," says Jetstar's Peter Symons.

As part of a larger network, Jetstar uses the Qantas Future Planet scheme which is one of the biggest programmes of any airline. There's an economy of scale associated that is quite different to Air New Zealand's equivalent programme, Fly Neutral.

Air New Zealand's insistence on local projects such as indigenous forest restoration in the Chatham Islands comes with a much higher overhead. This puts the airline's to around $23 a tonne. A steep increase from the $5 per tonne via climatecare.com's global carbon sink projects - the cheapest I could find.

"Needless to say, carbon credits purchased from New Zealand projects are currently much more expensive than those purchased from offshore projects," said a spokesperson for FlyNeutral.

However, there are extended benefits to supporting a local project. If you care about your impact beyond carbon footprint, it is worth choosing a regular scheme to support. This doesn't have to be done at time of booking.

You can calculate and buy credits at both airnewzealand.co.nz/flyneutral or qantasfutureplanet.com.au, to choose if you want your contribution to support kauri forests or regenerating the Australian bush. Both would be worthy projects in the current climate.

Wishing you a safe and carbon neutral journey,
Thomas

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