Catching a flight for your Christmas holidays?
Before you book that trip to the Gold Coast, remember your flight there and back will leave an extra tonne of fossil carbon dioxide in the atmosphere.
To take that carbon back out of the air, everyone on those planes will need to plant 700 native trees when they get back.
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The good news is that those trees will keep growing, so once they are in the ground, they will be taking excess carbon out of the atmosphere for years to come.
Maybe, like me, you'll be taking your holidays closer to home.
Driving the family from Auckland to Hot Water Beach and back will add about 70kg of carbon dioxide to your carbon footprint.
You can offset that by planting about fifty native trees, so before you leave, sign up with the Motutapu Restoration Trust to spend a Sunday planting on the island.
If planting trees isn't your thing, why not hire an electric vehicle for your trip?
Car share companies like Yoogo Share and Mevo have EVs in the main centres, while many of the major hire car companies now offer electric vehicles too.
Instead of filling up at the pump, you can charge up along the way using the network of fast charging stations around the country, or plug your EV in overnight once you've reached your destination.
One warning though - once you've driven an EV, you'll find it hard to go back to the old internal combustion engine. So last century.
But if you don't fancy those hot sticky days stuck on the holiday highway with just the kids and a traffic jam for company, why not catch the train?
The Northern Explorer, which runs between Auckland and Wellington every other day, takes in some of the best scenery that the North Island has to offer.
The train is diesel-electric, so a trip from Auckland to National Park will put 10kg of carbon dioxide into the air per person.
To offset this, you might consider planting a few extra natives in your backyard. You'll have less lawn to mow.
Or what about a stay-cation?
Spend the summer break exploring Auckland's gorgeous beaches and parks.
With a growing network of cycle paths, you can explore on that electric bike that your special someone did their best to wrap and hide behind the Xmas tree.
Grab some sunscreen, a beach towel and your bicycle helmet, and reclaim your city while all those gas-guzzling pollution-mobiles are out of town.
• Professor Shaun Hendy is a scientist, frequent traveler, and author of #NoFly, a book that describes his year on the ground. In the last two weeks of November, Shaun Hendy will travel around New Zealand by train, ferry and bus to deliver five public talks on how we can "fly less". People can watch his first public talk, chaired by Newsroom journalist Eloise Gibson, at the Pioneer Women's Hall at Auckland's Ellen Melville Centre between 2pm and 3pm this Sunday.