This plane used only one-third of the fuel used by a (larger) jet airliner on the same route. Photo / NZME
Is there a serious alternative to carbon-belching flight for the tree-hugging domestic traveller? Otago Daily Times journalist Peter Dowden takes a return trip to Auckland to find out.
1. DUNEDIN TO WELLINGTON BY JET PLANE: PLANT A TREE, FLY WITH ME...
Jet planes take you to lovely places, full of swaying palm trees (although they only have metal ones in Wellington) and at speeds little short of a miracle.
But flying in a jet is like directing two kerosene-powered flame-throwers at our planet.
No, you do not climb the tree to gain extra altitude, it's to eat up all the nasties that their jet engines emit.
The theory is simple: the harmful carbon (in petroleum form) has been under the ground for millennia; all we have to do is sequester the carbon back into a forest for several more millennia.
Air New Zealand's booking website was able to advise that my 1264km flight would make 176.7kg of CO2 per passenger (which seems like quite a lot, about double my own weight).
My cost to offset this CO2 was a reasonable $6.30.
Air New Zealand has been maintaining a fleet of high-tech aircraft for 75 years, so hugging a few low-tech trees for a million-odd years should be within its capabilities.
Its environment trust's first project at Mangarara Station in Hawkes Bay involves planting 85,000 trees over three years to create a public reserve.
I did wonder, given the price for cleansing the atmosphere is so reasonable, why not just load it on to everyone's fare?
But then I would have missed the fun I had on the rest of my eco-conscious journey.
2. WELLINGTON TO PALMERSTON NORTH BY RAIL: USE YOUR BRAIN, TAKE THE TRAIN...
Trains use far less fuel than planes, but also less than cars and buses as steel-on-steel friction is lower than rubber on asphalt.
That might not work in KiwiRail's case as their trains are not particularly modern.
Mine was a string of brown-and-beige second-hand British carriages, sort of Morris Marinas on rails, hauled by a 50-year-old locomotive.
KiwiRail now thinks of itself more as a leisure company providing rail-borne cruises rather than a means to get to where you need to go, leaving this train, the Capital Connection, as New Zealand's only serious inter-city train.
My Friday evening train was full of suited business types (the ones you would expect to see on a plane) heading back to the Manawatu after their busy day or week in Wellington.
The on-board bar was doing a roaring trade and the train was overtaking all the cars on the adjacent congested highway.
It's hard to find anything wrong with this service (fast, popular) but easy to find a reason why some would avoid it: it is expensive, and KiwiRail has declared another periodic fare increase ''as part of the ongoing drive to ensure commercial viability''.
Marketing genius straight from the 1970s, just like their carriages.
Other transport companies ensure commercial viability the 21st-century way, by giving discounts for midweek travel and advance bookings.
3. PALMERSTON NORTH TO AUCKLAND BY SLEEPER BUS: AVOID SIN, BOOK A TWIN...
Buses take you to nasty places where you don't want to go, like work or school or woodwork class.
Almost everyone agrees that buses are a brilliant idea and that more people should travel on them, although when pressed, most can provide an excellent excuse why this only applies to other people.
I know I have been bad, with all that jet flying, so it is time to atone.
I heave my luggage on to my back and shuffle to Palmerston North's stunningly beautiful central square of 1960s British brutalist architecture.
Nakedbus has introduced the first sleeper bus in New Zealand.
Boarding this vehicle brings back all those school camp memories as I look down the row into diminishing blackness between steely rows of double bunks down each side of the aisle.
Those ''other people'' are in abundance, peering at me with pale faces in the gloom as I shuffle along to my allotted niche.
I slide my nearly half-a-millimetre-thick curtain closed, concealing a space private enough to sleep in the style implied on the bus' signwriting, if I so wished.
I am cocooned in spotless sheets, the world's worries left outside the bus as I descend into the warm embrace of asphalt and rubber, the diesel engine purring away like a mother's heartbeat as the air conditioning ducted to every part of the bus drowns out the sounds and any olfactory trace of my fellow passengers.
Then the most dreadful thought dawns on me.
That not-so-thick curtain wasn't separating my bed from the aisle, it was dividing my bed. One of those dreaded ''other people'' was about to join me.
I could be snuggled up all the way to Auckland with Joe or Josephine Public.
Grabbing my iPad, I revisit the booking website and notice the box I should have ticked to book the entire twin berth.
Naturally, like anyone receiving distressing news via the internet, I drown my sorrows on the free Wi-Fi until a box pops up telling me I have used up my allocation.
Then blessed sleep, hours and hours of the best kind of it.
Joe or Josephine never turned up.
This was the big discovery of my trip: a night bus really can be a decent way to travel.
I had always planned to sleep this night, and I wasn't planning to do anything in particular while asleep, but this way I could sleep and get to Auckland at the same time.
But why do they suppose people only want to travel like this at night?
4. AUCKLAND TO WELLINGTON BY DOUBLE-DECKER EXPRESS BUS: SCORE ROW 1, TWICE THE FUN...
Daytime intercity bus travel and double-deckers are not particularly new, but ManaBus' new service is worth mentioning because it is also claimed to be a faster, environmentally friendly alternative to air travel.
One of the biggest bus companies in the world, Scotland-based Highland Global Transport squeezes in 79 people and their (severely limited) luggage into each ManaBus, and claims to consume only three litres of fuel per person between Auckland and Wellington.
Their other trick is to run strictly city to city, with no time-consuming halts in small towns, unlike most other New Zealand bus operators.
In lieu of rest breaks they provide tea, coffee and ice creams and a toilet on board.
And there's Wi-Fi, of course, which seems to be the thing these days.
I was lucky enough to score a top front-row seat (seriously, they don't charge extra for this?) so I had a corporate-box view of the North Island's mediocre, corkscrew-like state highway network.
Some people would find the amplified swaying on the top deck a little disturbing; downstairs is the place to be if your constitution is less than cast-iron.
5. WELLINGTON TO DUNEDIN BY TURBOPROP PLANE: SAVE THE WORLD, GET PROPELLED...
I regard travelling on turboprop planes much as I regard going to the dentist: you sort of have to go and at least it doesn't take all that long.
These old-fashioned looking planes are supposed to be quieter these days with less vibration, and mine was all executive-look with snazzy black leather which gave it a more modern feel.
But did you know, just like dentists, turboprops are good for you?
A pilot on my flight was able to confirm this last point: his plane used only one-third of the fuel used by a (larger) jet airliner on the same route, so with the fuel needed to carry 180 jet passengers, he could do three trips and carry 210 people (one-sixth more than the jet).
The time penalty for a slower plane is not much on such a short trip, and is all regained by faster luggage handling.
So, my trip ended with another solution to the conundrum: travel in a plane that burns less fuel per passenger.
Less glamorous than a jet, less convivial than a train, more isolated than a Wi-Fi-equipped bus.