The latest debate in the knotty issue of personal carbon footprint is whether it’s worse to have dogs than fly in a private jet. This absurd new wheeze came from Patrick Hanson, the CEO of Luxaviation, chiefly a private jet charter company, who came up with the ingenious idea of comparing greenhouse gas emissions from the two.

Hanson’s claim was that one of his customers produced an average of 2.1 tonnes of CO2e (total greenhouse gases expressed in terms of equivalent CO2) a year, which amounts to the same as owning three dogs, as estimated using a calculator created by Mike Berners-Lee, author of There is No Planet B.

His calculation for a single, largeish dog works out at around 770kg tonnes CO2e.

It seems quite hard to believe that dogs should be having such an impact. Perhaps, I found myself thinking that these were three very big and very greedy dogs, genetically modified giants of the canine world.

But, no, we're talking about regular biggish-sized dogs. And actually what struck me most was the very low figure Hanson gave for his customer, of just 2.1 tonnes – which made me wonder if he had cherry-picked a single customer who had done one relatively short flight.

Earlier this year, the UK policy manager for the campaigning organisation Transport and Environment, Matt Finch said: “A private jet is the most polluting form of transport you can take. The average private jet emits two tonnes of carbon an hour.”

In other words, we’re probably looking at just one hour of private jet flight for those three dogs.

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Hanson’s statement triggered a string of articles about just how bad pets are for the planet, and how we can reduce our pet’s impact. I’m not denying that we should look into and limit this impact – whether that be cats killing birds, or the contribution of pet food to global emissions – but you do have to wonder at this absurd attempt at deflection.

Hanson compares dogs to private jet charters. The more personal question, of course, since many of us do fly, mostly cattle-class on budget airlines, is how the emissions stack up in terms of scheduled flights versus dogs.

A quick check on a carbon footprint calculator for an economy class return from Edinburgh to Malaga estimates emissions to be 0.65 tonnes of CO2e. Make that, for example, a family of four and you have 2.6 tonnes.

Let’s compare that with dog emissions, which appear to be a little trickier to calculate. The key issue with our canine friends is the emissions created in feed production –  it’s worth noting that dry food, generally has a lower footprint than wet food.

Responding to Hanson’s claim, Dr Peter Alexander, senior lecturer in global food security at the University of Edinburgh, crunched a few figures. Some studies, as he pointed out, come out with shockingly high figures. “One,” he said, “published last year, suggested that feeding a 10kg dog (roughly the size of a standard dachshund) wet food is associated with the equivalent of 6,541kg of CO₂ emissions each year. This equates to 98% of the total emissions of an average Brazilian citizen. By contrast, a dry food diet for the same dog would result in emissions equivalent to 828kg of CO₂.”

Dr Alexander, however, also notes that research into environmental impact of pet food is limited and that many studies don’t take account of the fact of the use of animal byproducts rather than human-grade meat in the feed.

When they do, he notes, the calculation looks more like this: “Food emissions of a 10kg dog would be the equivalent of 240kg of CO₂ emissions per year. Scaled up for an average 22kg dog, that’s 530kg of CO₂ emissions each year.”

A big issue I have with Hanson's comparison is it seems an entirely transparent effort to shift the blame from the super-rich to the vast majority of us who are lower down the socioeconomic scale, and from jet-shaming to pet-shaming.

Sure, there are dog owners amongst the super-rich, and, in the UK, studies have shown the vast majority of people with dogs are white and of middle income, but there are also people who own dogs who struggle to feed and keep their pets whilst living in relative poverty. 

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Those involved in the flight business are always trying to say that flying is not too bad – to reframe the emissions from flights so that they seem relatively minor in the scheme of things.  This is clearly because we are quite some way off developing the technology for even short-haul emissions-free commercial flights, and in the meantime, the obvious way to reduce emissions from flights is to fly less.

We are in such straits, in a world that is likely to breach 1.5 degrees within four years, that the effort to reduce global air miles has to be ramped up, especially among those massive emitters, the super-rich.

But instead, we have private jet charter providers telling us that dogs are the problem. We can see through this. It's no more than a daft flight of fancy. Send it to the doghouse.