I went to a screening of The People’s Emergency Briefing — the climate film backed and narrated by Chris Packham, which has been shown free at halls, community centres and leisure centres all over the country this year.
At the end of the one I went to, we were asked to do something I have been thinking about ever since. Each of us was to name one change we would actually make.
About thirty-five people answered. The two commonest were giving up meat, something about flights, and some fears about the impact of data centres.
Nobody in that room was posturing. They had given up an afternoon, they had sat through something genuinely hard to watch, and they were offering the thing they thought they could honestly commit to. The willingness was not in short supply.
What was in short supply was the arithmetic.
What the answers are worth
| The change | Tonnes of CO2e saved a year |
|---|---|
| Running one typical car | 2.35 |
| One long-haul return flight | 1.6 |
| Going vegetarian | 0.8 |
| Recycling everything, thoroughly | 0.21 |
| Hang-drying the laundry | 0.21 |
| Changing every bulb in the house | 0.1 |
The car figure is one small petrol car doing 8,000 miles a year. A large one doing 12,000 is nearer 4.4 tonnes, and a household running two is over 9.
Going vegetarian is a serious answer and I do not want to be glib about it. 0.8 tonnes is real. But set it against the effort: going vegetarian is every meal, every day, for the rest of your life. Selling a car is an afternoon.
That is the comparison I think the room needed and did not have. Not the tonnes. The tonnes for the effort.
Why the car never gets named
I think that is because the car does not feel like a choice in the way dinner does. It feels like infrastructure. It is how you get to work, how you see your mother, how the shopping arrives. Asking someone to give it up sounds like asking them to give up their legs — whereas asking them to eat differently sounds like asking them to eat differently.
What happened when I stopped driving
But for me owning a car is also a bit of a trap, you find yourself using it for all of your trips, as this spreads out the cost of maintaining it more thinly. But so many journeys are so riven with traffic, they’re no fun. So my personal story as well as being able to get rid of the car, it coincided with me training to run Marathons. I was running a monthly 10k in Regents Park, and that was a 4 mile drive — about 25 minutes to drive there and to park, and I realised I could run it in 10 more minutes and get more training in.
I found myself trying always to travel to do exercise without driving, suddenly it’s the warm up, it’s extending your training, you’re getting fitter and stronger.
And then getting back on the bus, and automatically sitting on the top front seats on the double decker, with that great view, that fear of hitting a traffic light as the bus swings around the corner, and then discovering a chance to chat to the kids on the bus, rather than shutting them up in the back of the car with some screen.
What I did about it
I built a thing that answers the question the room didn’t have. Put in your postcode and it will tell you whether you live somewhere well served for non car transport and what your own car costs you a mile — not the fuel, the whole thing — what share of your household’s carbon it is, and what proportion of your actual neighbours already manage without one.
And for many people in many places it will tell them they need a car. That is not a failure. In a village forty minutes from anywhere, “give up the car” is not a climate action, it is a fantasy, and pretending otherwise is how this conversation loses people.
Where these numbers come from, and how much to trust them
The comparison figures are from Wynes and Nicholas, The climate mitigation gap, Environmental Research Letters, 2017 — the only study I know of that ranks these choices on one consistent method, which is why the ratios between them hold up better than the absolute values do.
They are means across studies in developed nations rather than UK figures, and the spread is wide: the paper puts the diet anywhere between 300 and 1,600 kg a year against a headline of 800, and a flight between 700 and 2,800 against 1,600. Its authors call them best estimates rather than firm figures, and so do I.
The car figures are not from that paper. They are calculated from the Department for Energy Security and Net Zero’s own 2026 conversion factors, on the same accounting boundary for every fuel, because choosing a kinder boundary for one side is how these comparisons usually get rigged.
If a number here is wrong, tell me and I will fix it.