My 6-year-old asked me about Santa the other day. Luckily, it wasn't the moment where his innocence is shattered forever.
Instead, he was wondering how Santa was going, preparing for his annual voyage around the world, dispensing plastic junk from China to all the world's least-needy kids. (I added the last part, but you get the drift).
I painted the picture that my parents had passed on to me. I explained to him how the night is slowly descending across the North Pole at the moment, and by the time Santa sets off on his sleigh across the ice on Christmas Eve, it will be shrouded in continuous darkness, lit only by his Christmas candles, and one shiny red nose.
My son is very interested in fashion, and so we talked at length about Santa's warm red jacket. The sad thing that I didn't have the heart to tell my son is that, at the moment, Santa's big red jacket is probably too warm for Santa himself, even at the North Pole.
Santa is a fantasy but climate change is not, and it's started to do truly alarming things to the North Pole.
Over the past few weeks the temperature of the North Pole has been 22 degrees hotter than the average temperature for this time of year. That's not a typo. It's not 2.2 degrees hotter. It's 22 degrees Celsius hotter.
The reason it's such a huge difference is because even though night is now falling, the temperature around the poles is still getting hotter rather than colder. That's never happened before. What it means is that the gap between average temperature and this year's temperature is getting wider and wider by the day.
Here is the graph that Zack Labe, a PhD student at Cornell University, who first discovered it, put out a couple of weeks ago:
The green line represents the pattern of temperature that's been the norm for the past 100,000 years or so. That lonely red line that started going down, but then decided to start going up again, is this year's temperature.
There are a lot of implications for this. In salt water, minus five degrees (which is the current air temperature in the North Pole) is too warm for ice to form. That means the planet's natural airconditioner (and sun reflector) is not regrowing back this winter. Two of the ways the earth keeps itself cool have just broken down.
When it comes to climate, I'm a pretty lousy citizen. I do all the things you're not supposed to do. I use a clothes dryer, I eat red meat, I even stopped offsetting my energy bills when I got my new mortgage.
It's not that I'm a climate sceptic - far from it. But I've become immune to reports about the gradual heating of the planet. I know I supposed to worry that last year, the planet was an average 1.10 degrees hotter than usual, but it's hard to get that worked up about it. It just feels too intangible.
But 22 degrees is different. This moment has long been theorised, and now it's here. This is the awful moment where the feedback loops start feeding into each other in a big way.
The ice caps melt because it's getting warmer and then because the ice caps have melted, the earth gets even warmer even faster.
Peter Wadhams, a professor of Ocean Physics at Cambridge University, now reckons that it could be as little as two years before ice disappears completely from the North Pole during the summer months.
I know this next bit is obvious, but I'm going to point it out anyway, because I didn't quite realise it until it was pointed out to me. What the ice melting at the North Pole means is that, once it's gone, you'll be able to drive a boat across the North Pole.
No more photos of intrepid tourists reaching the North Pole, doing a cheesy thumbs in front of a sign saying "North Pole". No more stories of Santa's sleigh. There will be no ice for him to drive his sleigh across.
In addition to the environmental implications, the cultural implications of this are also huge.
We will need to start changing the stories that we tell ourselves and our children about what our planet looks like. The idea that ice was once at the North Pole will become folklore, much like the fabled North-West passage through the Arctic, which as recently as a decade ago was considered treacherous and impassable, but has now become a common route for ships and tourist boats in the summer months.
This is why I'm seriously considering taking the kids out of school next July, and taking them up to the North Pole to see the ice. It's probably the last chance to see it. Fantasies of the North Pole are such a vivid part of my own childhood. When was a kid, I always assumed I'd go there one day. Now I know my children will not.
If I do take my kids to see the North Pole and they live long lives, they'll end be some of the last people on earth to be able to attest that there was indeed, ice at the top of our planet.
I know I should probably explain some of this to my son. I know I probably shouldn't be passing on the myths that my parents passed on to me. But in the same way I can't bring myself to break it to him that Santa doesn't exist, I also don't have the heart to break it to him that climate change does. For that is a shattering of his innocence that he'll be dealing with for the rest of his life.
Charles Firth majored in Economic (Social Science) at Sydney University. He is also editor of The Chaser Quarterly. Follow him on Twitter @charlesfirth