Air travel risks sending carbon emissions up, up and away.
We're travelling by air more than ever. Whether for business or leisure, the speed and convenience, not to mention relative affordability, makes air travel an increasingly popular option for New Zealanders.
The speed at which we can travel to Wellington makes day trips possible, something that would have previously not been an option.
So now a Dunedin-based businessperson can attend meetings in Auckland, Wellington and Christchurch in one week, without missing an evening at home with their family.
Imagine having to drive or catch a train all the way to Auckland for a one-day meeting.
Or catching a ferry to the Gold Coast for a short break.
It doesn't sound very appealing does it?
So air travel is very convenient.
Few people actually prefer hotel rooms to their own home, and even fewer still want to spend time away from their loved ones.
So it means we can have the best of both worlds.
But this convenience comes at a cost.
Air travel is a carbon-intensive transport mode.
Per passenger kilometre, air travel emits more carbon into the atmosphere than any other mode.
But it isn't just carbon dioxide that we have to think about.
Aviation also contributes to radiative forcing* of the climate through emissions of nitrogen oxides, aerosols (soot and sulphate) and issues relating to linear contrails.
Because of these emissions, air travel accounts for about 5% of total human-induced climate forcing and 10.6% of all transport-direct greenhouse gas (e.g. carbon dioxide, methane, nitrous oxide etc) emissions.
And these emissions are not reducing in the way we need them to in order to adequately respond to climate change.
In fact, in countries with advanced economies, such as New Zealand, emissions from international aviation are increasing.
Between 1990 and 2011, these emissions rose 53%.
The aviation industry has been relatively successful in increasing its operational efficiencies.
For example, code sharing means it is quite rare to have spare seats in planes nowadays.
But growing demand for air travel is outweighing these efforts.
Globally, passengers are forecast to more than double, from 3.1 billion in 2013 to 6.63 billion by 2032.
So what can we do?
As travellers or tourists, I think we need to consider the viability of alternative modes.
For example, did you know that from Dunedin, we can travel to Wellington by a mix of public modes (bus, train, ferry), and arrive within 24 hours?
Maybe we need to be more creative about how we get around and to be more considerate about whether the travel is necessary (virtual travel, anyone?).
Perhaps travelling less frequently but for a longer duration could be an option for both business and leisure purposes?
Whatever the response, it is important that everyone is aware that transport choices matter.
So whether you're travelling around Dunedin, or travelling domestically, or internationally, try to make low-carbon transport choices where possible.*
Radiative forcing is a direct measure of the amount that the earth's energy budget is out of balance.
• Debbie Hopkins is a postdoctoral research fellow at the University of Otago Centre for Sustainability. Each week in this column, writers address issues of sustainability.
