“Carbon emission offsets for aviation-generated emissions due to international travel to and from New Zealand”, Inga Smith, et al, Energy Policy, 37 (2009), pp 3438, 3447
NZ’s greenhouse gas emissions have grown by 25% since 1990, but emissions from international tourism grew by 172%. Holy crap. So what can be done about it?
- Tourism is growing at 4% per year, the less it grows, the less emissions grow, but then again, the less money tourism makes.
- Replacing visitors from the other side of the world with visitors from close by would reduce emissions per journey, but then again, there’s only 20 million Ozzies, and most of them have been here already.
- More efficient planes? Has been happening for decades already, but fuel efficiency for planes only improve by 1% per year, when tourism’s going up by 4%. So necessary, but nowhere near enough.
- Therefore, offsets!
Offsetting has grown up in the past five years, from nothing to a billion dollar business for voluntary offsets alone. They make a difference, but do they make enough of a difference. The paper above runs the numbers to work out how much offsetting is required to cover just one year of aviation to and from NZ. Answer – oh crap. To cover just one year, we’d need to have regenerating bush over 10% of NZ’s land area. That’s fifteen Stewart Islands, and cutting dairy land by half. Oops.
Still, offsetting is more than just planting trees, it’s anything that can reduce emissions. So we could use energy efficient lightbulbs, but we’d need to install 100 lightbulbs per international visitor. Or reduce road transport by 60%. And that’s just not going to happen.
So it’s pretty clear that offsetting helps and is necessary to buy us time to make serious reductions. However, if every flier did it, we’d end up running out of land to plant trees. In a carbon-limited world, aviation as we know it is doomed. International travel cannot continue to grow.*
* – unless there’s an out of the blue technological solution to this. It’s not flying wings, they’re efficient, but not that efficient. It’s not hydrogen, coz the fuel tanks will take up most of the plane. It might be biofuels if land transport goes electric, otherwise there won’t be enough biofuels to go around. It might be nuclear aircraft, in an alternative universe.