Islands and Offsets

​Brr… it’s cold!  We’ve put a wood burner in the lounge, a heat pump in the hall, a heap of insulation in the attic and underfloor and I’ve still got the winter chills!  It is time to go to some warm place to thaw out!
“Marg, what say we take a holiday in Fiji?  Think of it – tropical beaches, warm sunshine, crystal clear waters.  It’s just what we need to get over these winter blues.”
Marg: “Hmmn, I just saw that Air New Zealand is having a special on island vacations, but you’ll need to get a new pair of togs.”
Me: “What’s wrong with my togs?”
Marg: “Let’s just say they’re looking a bit tight on you.  All the healthy whole foods we’ve been eating is catching up with you, I guess; that and the Mac’s Green Beret.
Google Assistant interrupts: “The cheapest flights from Blenheim to Fiji with the best connections, leaving in two weeks’ time will cost between $1000 and $1200 per person roundtrip.”
Me: “Crikey that will stretch us a bit.  I suppose we still have some cash after the heat pump and wood burner install, since the Council paid for most of it.”
Marg: “And we’ll need to add the cost of the carbon offsets.”
Me: “Carbon whats?”
Marg: “Offsets for the carbon dioxide emissions we’ll be creating by flying. Come on Tom… you remember! Airline flights create greenhouse gas emissions.  We’ll need to offset these. We can do this by buying into a scheme that offsets these emissions, like by growing trees, to sequester the carbon back out of the atmosphere.”
Me: “Well, that’s a good idea!  Maybe we don’t need to give up fossil fuels after all.  We can just plant more trees to offset our emissions.”
Marg: “Offsets are only a temporary solution.  We’ll soon run out of places to plant more trees.  Now focus, Tom, Fiji!
Google pipes up again: “The round trip from Blenheim to Nadi, Fiji is 5328 kilometres and will generate 438.7 kilograms of CO2.  Offsetting these emissions through Air New Zealand’s Fly Neutral program will cost $9.36.”
Me: “$9.36? What’s that going to do?”
Google: “The Air New Zealand’s program invests in native forest restoration in New Zealand. It also invests overseas. Examples include a wind farm in New Caledonia, biogas from animal waste in Vietnam and solar ovens in China.”
Google: “Keep in mind, however, that Air New Zealand’s offsets only cover the CO2 emissions from aircraft exhaust and do not include the additional radiative forcing associated with jet airplanes…”
Me: “Radiative what?”
Google: “Radiative forcing accounts for the global warming effects of ozone, water vapour and vapour trail created by jet aircraft exhaust in the stratosphere.  The Blenheim to Auckland leg of the journey will be in a low flying turboprop which creates little radiative forcing. The Auckland to Fiji leg will be in a jet flying in the stratosphere where radiative forcing is greatest.”
Me: “I knew there had to be a catch.  Google, you are such as spoil sport!  So, how much is this all going to cost?”  
Google: “The science is still somewhat uncertain, but the best estimates of radiative forcing is that it adds 90% to the warming due to exhaust CO2 alone.  Including radiative forcing in your flight to Fiji and back would add 320 kg CO2 equivalent, or $6.83 in offsets, for a total bill of $16.19.”
Google: “Since Air New Zealand doesn’t include radiative forcing in its offset calculations, you will need to offset using another company.  EKOS in Takaka provides offsets for native forest rehabilitation projects on the South Island.
Me: “An additional $16.19, eh?  That’s about the cost of a six pack of Green Beret!  I suppose we can afford it.”
Marg: “Maybe with a few less six packs you might fit into those togs again!”